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TRANSCRIPT
CH
APT
ER 3
Th
e E
ner
geti
cs o
f R
epti
lian
Act
ivit
y
AL
BE
RT
F. B
EN
NE
TT
Sc
hool
of B
iolo
gica
l Sci
ence
s, U
nive
rsity
of C
alif
orni
a at
Irv
ine,
Irv
ine,
Cal
ijbrn
ia,
U.S
.A.
I. G
ener
al I
ntr
od
uct
ion
Mos
t of t
he e
arly
inve
stig
atio
ns o
f ene
rgy
utili
zatio
n by
rep
tiles
invo
lved
th
e m
easu
rem
ent
of r
esti
ng m
etab
olic
ra
tes.
The
se s
tudi
es s
ough
t to
es
tabl
ish
the
cost
of
livin
g of
qui
et, u
ndis
turb
ed a
nim
als
and
to s
et a
low
er
boun
dary
on
ener
gy d
eman
ds,
that
is,
on
the
min
imal
am
ount
of
ener
gy
requ
ired
fro
m t
he e
nvir
onm
ent.
Bec
ause
res
ting
met
abol
ic ra
tes
vary
with
te
mpe
ratu
re i
n th
ese
ecto
ther
mic
ani
mal
s,
the
ther
mal
de
pend
ence
of
met
abol
ism
was
oft
en t
he o
rgan
izat
iona
l th
eme
of t
hese
stu
dies
. T
hese
in
vest
igat
ions
wer
e su
cces
sful
in
perm
itti
ng t
he e
stab
lish
men
t of
qua
nti-
ta
tive
allo
met
ric
rela
tion
ship
s at
dif
fere
nt
body
te
mpe
ratu
res
betw
een
body
mas
s an
d m
inim
al e
nerg
y de
man
d. T
hese
rel
atio
nshi
ps h
ave
been
de
velo
ped
and
repo
rted
by
seve
ral a
utho
rs (B
arth
olom
ew a
nd T
ucke
r, 1
964;
T
empl
eton
, 19
70;
Dm
i'el,
1972
; W
ilson
, 19
74a;
Ben
nett
and
Daw
son,
19
76).
Con
sequ
entl
y, t
he e
nerg
etic
requ
irem
ents
of m
aint
enan
ce e
xist
ence
m
ay n
ow b
e pr
edic
ted
for m
ost r
eptil
es o
f kno
wn
body
siz
e an
d te
mpe
ratu
re.
In a
ddit
ion,
the
se g
ener
aliz
ed r
elat
ions
may
als
o se
rve
as t
he b
asis
fro
m
whi
ch t
o co
mpa
re e
nerg
etic
ada
ptat
ions
of
diff
eren
t sp
ecie
s w
ith s
ome
spec
ial
feat
ure
of i
nter
est
(e.g
. ha
bita
t, bo
dy s
ize,
phy
loge
netic
gro
up).
E
xam
inat
ions
of
the
mai
nten
ance
ene
rgy
requ
irem
ents
of
rept
iles
have
fo
und
them
to
be
ve
ry
sim
ilar
to
th
ose
of
amph
ibia
ns,
fish
, an
d in
vert
ebra
tes,
and
an
orde
r of m
agni
tude
bel
ow th
ose
of m
amm
als
and
bird
s (H
emm
ings
en,
1960
). W
ith
the
delim
itatio
n of
min
imal
req
uire
men
ts,
inte
rest
aro
se i
n th
e op
erat
ion
of t
hese
ani
mal
s du
ring
sus
tain
ed a
nd m
axim
al e
xert
ion.
Stu
dies
ha
ve a
ttem
pted
to m
easu
re th
e co
sts
of lo
w l
evel
, sus
tain
able
act
ivity
of t
he
sort
in w
hich
mos
t rep
tile
s eng
age
on a
dai
ly b
asis
. An
exam
inat
ion
of e
nerg
y ut
iliza
tion
duri
ng in
tens
e ac
tivity
per
mit
ted
an a
naly
sis
of m
axim
al e
nerg
y
156
AL
BE
RT
F.
BE
NN
ET
T
util
izat
ion
and
set a
n up
per
lim
it o
n en
ergy
dem
and
and
proc
essi
ng.
It a
lso
led
to d
eter
min
atio
n of
dif
fere
ntia
l m
etab
olic
sup
port
for
its
mai
nten
ance
. T
hese
tw
o ty
pes
of s
tudi
es o
n ac
tive
rep
tile
s ha
ve r
evea
led
them
to
be
anim
als
of g
ener
ally
low
sta
min
a bu
t ca
pabl
e of
im
pres
sive
bu
rsts
of
shor
t-te
rm
acti
vity
. T
he
beha
vior
al
repe
rtoi
re
of
rept
iles
re
flec
ts
the
lim
itat
ions
impo
sed
by t
he m
etab
olic
sys
tem
s us
ed i
n tr
ansd
ucin
g en
ergy
. T
hese
the
mes
will
be
exam
ined
and
exp
ande
d in
thi
s ch
apte
r. A
fter
an
init
ial d
iscu
ssio
n of
the
met
abol
ic s
uppo
rt fo
r ac
tivi
ty, t
he d
egre
e an
d co
sts
of s
usta
inab
le a
ctiv
ity
will
be
exam
ined
. Th
e re
lati
onsh
ips
of b
urst
act
ivity
an
d it
s co
nseq
uenc
es f
or e
nerg
y ut
iliz
atio
n w
ill a
lso
be d
iscu
ssed
. T
his
are
a of
res
earc
h is
exp
andi
ng r
apid
ly a
t pr
esen
t. M
ost
of o
ur
know
ledg
e ha
s be
en g
athe
red
wit
hin
the
past
dec
ade.
In
ano
ther
ten
year
s w
e w
ill h
ave
a su
bsta
ntia
lly
expa
nded
dat
a ba
se, b
oth
phyl
ogen
etic
ally
and
ex
peri
men
tall
y,
from
w
hich
to
ge
nera
lize
. T
his
pre
sent
re
view
w
ill
sum
mar
ize
the
find
ings
of
the
fift
y-od
d in
vest
igat
ions
int
o th
ese
prob
lem
s an
d at
tem
pt t
o po
int
to a
reas
in n
eed
of f
urth
er r
esea
rch.
Fro
m th
e ou
tset
, ho
wev
er,
it is
im
port
ant t
o ke
ep i
n m
ind
the
lim
itat
ions
of
inte
rpre
ting
the
da
ta a
vail
able
to
us.
The
re a
re t
wo
prin
cipa
l sh
ortc
omin
gs w
hich
sho
uld
inhi
bit
our
spec
ulat
ion
and
gene
rali
zati
on,
or a
t le
ast
lead
us
to p
roce
ed
mor
e ca
utio
usly
. Fir
st,
the
phyl
ogen
etic
sco
pe o
f the
obs
erva
tion
s av
aila
ble
is n
ot b
road
. Th
e nu
mbe
r of
spe
cies
that
hav
e be
en s
tudi
ed is
sm
all,
and
the
spec
ies
stud
ied
are
not
nece
ssar
ily
repr
esen
tati
ve o
f th
eir
taxa
. N
earl
y on
e-ha
lf
of o
ur d
ata
have
bee
n ob
tain
ed,
for
inst
ance
, fr
om t
he i
guan
id
liza
rds
of N
orth
Am
eric
a. S
econ
d, e
ssen
tial
inf
orm
atio
n ab
out
the
ecol
ogy
and
beha
vior
of
thes
e re
ptil
es a
ctiv
e in
the
fie
ld is
alm
ost
none
xist
ent.
It is
co
nseq
uent
ly d
iffi
cult
to c
orre
late
per
form
ance
det
erm
ined
in
the
labo
ra-
tory
wit
h na
tura
l fun
ctio
n or
to k
now
n th
e ex
tent
to w
hich
ani
mal
s ar
e tr
uly
"act
ive"
or
"se
dent
ary.
" T
he
form
er o
f th
ese
diff
icul
ties
will
be
over
com
e w
ith
the
accu
mul
atio
n of
lab
orat
ory
obse
rvat
ions
on
a gr
eate
r nu
mbe
r of
se
lect
ed s
peci
es.
Th
e la
tter
req
uire
s a
mor
e qu
anti
tati
ve a
ppro
ach
in t
he
cons
truc
tion
of
tim
e an
d ac
tivi
ty b
udge
ts b
y be
havi
oris
ts a
nd e
colo
gist
s.
Som
e as
pect
s of
act
ivit
y an
d ac
tivi
ty m
etab
olis
m i
n re
ptil
es h
ave
been
pr
evio
usly
rev
iew
ed b
y th
e fo
llow
ing
auth
ors.
Ben
edic
t (19
32) r
evie
wed
the
ea
rly
lite
ratu
re a
nd m
ade
subs
tant
ial
cont
ribu
tion
s on
ene
rgy
util
izat
ion,
pa
rtic
ular
ly i
n la
rge
rept
iles
. T
he
ther
mal
dep
ende
nce
of a
ctiv
ity
met
abo-
lis
m w
as r
evie
wed
by
Daw
son
(196
7, 1
975)
and
Tem
plet
on (1
970)
. Var
ious
as
pect
s of
rept
ilia
n m
etab
olis
m a
nd e
nerg
etic
s, p
rim
aril
y in
res
ting
rep
tile
s,
wer
e pr
esen
ted
by B
enne
tt a
nd D
awso
n (1
976)
. P
atte
rns
of a
ctiv
ity
and
met
abol
ism
w
ere
com
pare
d am
ong
rept
iles
, am
phib
ians
, an
d fi
sh
by
Ben
nett
(19
78).
Th
e in
terr
elat
ions
of
beha
vior
and
act
ivit
y ph
ysio
logy
of
rept
iles
are
dis
cuss
ed b
y R
egal
(19
78),
Ben
nett
and
Rub
en (
1979
), P
ough
(1
980,
in
pres
s),
and
Ben
nett
(19
80a,
198
1).
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
15
7
11. S
ust
ain
able
Act
ivit
y a
nd
Its
Aer
obic
Su
pp
ort
Use
ful
wor
k an
d lo
com
otor
y ac
tivity
inv
olve
the
con
vers
ion
of e
nerg
y st
ored
in
the
mol
ecul
ar b
onds
of f
oods
tuff
s in
to a
form
that
is m
ore
dire
ctly
av
aila
ble
to a
n or
gani
sm.
Seve
ral s
uch
conv
ersi
ons
are
poss
ible
for
rep
tiles
an
d th
ose
that
pre
dom
inat
e de
pend
upo
n th
e in
tens
ity o
f th
e ac
tivity
un
dert
aken
. Res
ting
ene
rget
ic r
equi
rem
ents
are
met
by
aero
bic
cata
bolis
m:
the
degr
adat
ion
of s
tora
ge c
ompo
unds
to
carb
on d
ioxi
de a
nd w
ater
(an
d ni
trog
enou
s ex
cret
ory
prod
ucts
in t
he c
ase
of p
rote
ins)
, th
e co
nsum
ptio
n of
ox
ygen
, an
d th
e si
mul
tane
ous
prod
ucti
on
of
high
-ene
rgy
phos
phat
e m
olec
ules
. A
con
tinu
ous
deliv
ery
of o
xyge
n to
met
abol
izin
g tis
sues
is
requ
ired
to
sus
tain
aer
obic
ene
rgy
prod
ucti
on.
As
the
leve
l of
act
ivity
in
crea
ses
abov
e re
st, a
ddit
iona
l am
ount
s of
oxy
gen
are
deliv
ered
to
supp
ort
incr
ease
d en
ergy
dem
ands
. T
he
lim
it o
f ae
robi
c m
etab
olic
sup
port
is
atta
ined
with
the
dev
elop
men
t of
max
imal
lev
els
of o
xyge
n co
nsum
ptio
n.
Fur
ther
in
crem
ents
in
ac
tivity
le
vels
m
ust
be
fuel
ed
thro
ugh
othe
r,
anae
robi
c so
urce
s of
ene
rgy
prod
ucti
on.
Unl
ike
stea
dy-r
ate
oxyg
en c
on-
sum
ptio
n, t
hese
can
not
be s
usta
ined
and
res
ult
in t
he a
ccum
ulat
ion
of
met
abol
ic e
nd-p
rodu
cts
with
in t
he ti
ssue
s or i
n th
e de
plet
ion
of h
igh-
ener
gy
phos
phat
e co
mpo
unds
. E
xhau
stio
n or
dim
inis
hed
beha
vior
al c
apac
ities
of
ten
follo
w b
outs
of
anae
robi
c m
etab
olis
m.
Res
earc
h on
aer
obic
act
ivity
cap
acit
y in
rep
tile
s ha
s co
ncen
trat
ed u
pon
dcte
rmin
atio
ns o
f m
axim
al o
xyge
n co
nsum
ptio
n an
d th
e le
vel o
f exe
rtio
n at
w
hich
it
is a
ttai
ned.
Th
e th
eore
tica
l fo
unda
tion
for
exa
min
ing
aero
bica
lly
supp
orte
d w
ork
in e
ctot
herm
ic o
rgan
ism
s w
as e
stab
lishe
d in
a c
ompa
ra-
tivel
y ea
rly
pape
r by
Fry
(194
7). A
ltho
ugh
this
wor
k ad
dres
sed
the
activ
ity
ener
geti
cs o
f fi
sh, i
t has
exe
rted
a c
ontr
olli
ng in
flue
nce
on t
he d
evel
opm
ent
of e
arli
er s
tudi
es o
n re
ptil
ian
acti
vity
as
wel
l. F
ry e
mph
asiz
ed th
e di
ffer
ence
be
twee
n m
axim
al a
nd r
esti
ng o
xyge
n co
nsum
ptio
n, a
fact
or te
rmed
the
scop
e jiw
act
ivit
y, a
s be
ing
the
pote
ntia
l of
an
orga
nism
for
doi
ng w
ork.
Th
e en
velo
pe c
reat
ed b
y th
ese
valu
es a
t di
ffer
ent
tem
pera
ture
s es
tabl
ishe
s th
e w
ork
capa
city
of
an e
ctot
herm
ove
r it
s en
tire
the
rmal
ran
ge.
Alth
ough
sc
vera
l sh
ortc
omin
gs o
f th
is c
once
pt w
ere
subs
eque
ntly
rec
ogni
zed
(sum
- m
ariz
ed i
n B
enne
tt,
1978
), th
is m
easu
rem
ent,
now
term
ed a
erob
~c scop
e or
~
ero
bic
met
abol
ic s
cope
(B
enne
tt,
1972
), is
stil
l a
wid
ely
used
com
para
tive
inde
x of
aer
obic
abi
lity
duri
ng a
ctiv
ity.
Th
e hy
poth
esis
tha
t m
axim
al
aero
bic
scop
e co
inci
des
with
max
imal
sus
tain
able
wor
k ca
paci
ty h
as b
een
valid
ated
fo
r se
vera
l sp
ecie
s of
li
zard
s (I
gunn
a,
Mob
erly
, 19
68a,
b;
Cne
mid
opho
rus,
B
enne
tt
and
Gle
eson
, 19
79;
Arn
b~w
hj~r
lchz
~s,
Gle
eson
, 19
79b,
198
0b;
Var
anus
, G
lees
on e
t al
., 19
80; D
ipso
saur
us, J
ohn-
Ald
er
and
158
AL
BE
RT
F.
BE
NN
ET
T
Ben
nett
, 19
81).
To
exa
min
e ae
robi
c sc
ope
and
max
imal
aer
obic
wor
k ca
paci
ty,
it i
s ne
cess
ary
to s
umm
ariz
e ou
r kn
owle
dge
of b
oth
rest
ing
and
max
imal
rat
es o
f ox
ygen
con
sum
ptio
n in
rep
tiles
.
B. R
ES
TIN
G
AN
D M
AX
IMA
L
AE
RO
BIC
PO
WE
R IN
PU
T
1. M
aint
enan
ce M
etab
olic
Lev
els
Th
e ra
te o
f ox
ygen
util
izat
ion
in r
eptil
es i
s st
rong
ly i
nflu
ence
d by
bod
y te
mpe
ratu
re, b
ody
mas
s, a
nd p
hysi
cal a
ctiv
ity. T
he
cont
ribu
tion
s of
eac
h of
th
ese
fact
ors i
s dis
cuss
ed in
det
ail b
elow
. How
ever
, cer
tain
asp
ects
ofe
ach
of
thes
e m
ust
be c
onsi
dere
d in
the
spe
cifi
catio
n of
res
ting
met
abol
ic l
evel
. O
xyge
n co
nsum
ptio
n of
the
liz
ard
Igua
na a
t re
st a
nd d
urin
g in
tens
e st
rugg
ling
act
ivity
is
show
n in
Fig
. 1.
Cle
arly
act
ivity
res
ults
in
grea
tly
incr
ease
d re
stin
g m
etab
olic
val
ues.
Und
oubt
edly
, m
any
of t
he p
ublis
hed
obse
rvat
ions
on
rept
iles
wer
e no
t obt
aine
d un
der
trul
y qu
iesc
ent c
ondi
tions
. E
stim
ates
bas
ed o
n su
mm
arie
s of t
hese
val
ues
shou
ld b
e re
cogn
ized
as b
eing
on
ly a
ppro
xim
atio
ns o
f re
stin
g m
etab
olic
rat
e,
and
not
as b
eing
tr
ue
stan
dard
met
abol
ic r
ates
. T
he
infl
uenc
e of
bod
y te
mpe
ratu
re o
n ox
ygen
co
nsum
ptio
n is
like
wis
e ve
ry g
reat
. M
etab
olic
dat
a, s
uch
as th
ose
in F
ig.
1,
have
con
sequ
entl
y be
en s
umm
ariz
ed a
t di
ffer
ent
body
tem
pera
ture
s as
0.01 l,
I I
I I
I I
I5
20
25
30
35
40
Tem
pera
ture
PC
)
FIG
. I.
Igua
na i
guan
a. R
esti
ng (o
pen
circ
les)
and
max
imal
(cl
osed
cir
cles
) oxy
gen
cons
umpt
ion
as a
fu
ncti
on o
f bod
y te
mpe
ratu
re. R
edra
wn
from
Mob
erly
(196
8a).
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
T~
LIA
N AC
TIV
ITY
159
func
tion
s of
bod
y m
ass.
The
se e
quat
ions
are
of
the
form
MR
=am
b, in
w
hich
MR
is m
etab
olic
rate
in o
xyge
n co
nsum
ptio
n or
pow
er in
put a
nd m
is
body
mas
s; a
and
b a
re e
mpi
rica
lly d
eter
min
ed v
alue
s. W
eigh
t-re
lativ
e or
m
ass-
spec
ific
met
abol
ic v
alue
s (o
xyge
n co
nsum
ptio
n or
pow
er i
nput
per
un
it m
ass)
are
obt
aine
d by
usi
ng (
b-
1) a
s th
e po
wer
exp
onen
t. E
quat
ions
for
res
ting
val
ues
of a
erob
ic m
etab
olis
m a
re s
umm
ariz
ed i
n T
able
I.
T
hese
re
gres
sion
s co
ncea
l co
nsid
erab
le
vari
abili
ty
in
thei
r co
mpo
nent
dat
a, m
uch
of i
t du
e to
exp
erim
enta
l di
ffer
ence
s in
da
ta
colle
ctio
n (B
enne
tt a
nd D
awso
n,
1976
). H
owev
er,
a ce
rtai
n am
ount
is
undo
ubte
dly
due
to t
axon
omic
, m
orph
olog
ical
, an
d/or
eco
logi
cal
diff
er-
ence
s am
ong
grou
ps o
f re
ptile
s. F
or in
stan
ce,
ener
gy u
tiliz
atio
n of
res
ting
xant
usii
ds i
s su
bsta
ntia
lly
belo
w t
hat
of o
ther
liz
ards
. T
his
met
abol
ic
depr
essi
on is
thou
ght t
o re
pres
ent
an a
dapt
atio
n fo
r lif
e in
env
iron
men
ts o
f lo
w p
rodu
ctiv
ity
(Mau
tz,
1979
). In
con
tras
t, la
cert
id l
izar
ds o
f th
e ge
nus
Aca
ntho
dact
ylus
hav
e m
etab
olic
rat
es in
exc
ess
of p
redi
cted
lev
els (
Duv
de-
vani
and
Bor
ut,
1974
; Pou
gh a
nd B
usac
k, 1
978)
. Th
e ad
vant
age
conf
erre
d by
thi
s au
gmen
ted
met
abol
ism
is
not
know
n. T
urtl
es h
ave
met
abol
ic r
ates
lo
wer
tha
n an
tici
pate
d fo
r rep
tiles
of
com
para
ble
mas
s; th
e po
sses
sion
of a
n es
sent
ially
met
abol
ical
ly in
ert s
hell
is th
ough
t to
acco
unt
for t
his
diff
eren
ce
TA
BL
E
I Th
e al
lom
etri
c re
latio
nshi
p of
res
ting
oxyg
en c
onsu
mpt
ion
in r
estin
g re
ptile
s.
TB
vo
z --
n of
G
roup
"C
m
lOz/
h mW
b r
spec
ies
Liz
ards
20
0.
096
0.54
0.
80
0.80
24
30
0.
240
1.34
0.
83
0.86
24
35
0.
450
2.53
0.
78
0.77
14
40
0.
575
3.14
0.
79
0.73
13
Sn
akes
20
0.
120
0.67
0.
77
0.80
35
30
0.
280
1.57
0.
76
0.91
13
T
urtl
es
20
0.06
6 0.
37
0.86
0.
78
10
All
rept
iles
20
0.10
2 0.
57
0.80
0.
83
73
30
0.27
8 1.
55
0.77
0.
91
44
35
0.44
5 2.
51
0.76
0.
57
21
40
0.56
2 3.
16
0.79
0.
55
16
Mas
s is
mea
sure
d in
g.
Dat
a at
20
and
30°C
fro
m B
enne
tt an
d D
awso
n, 1
976;
dat
a at
35
and
40°C
cal
cula
ted
from
ref
eren
ces l
iste
d in
Tab
le 1
1. T
~=
bo
dy
tem
pera
ture
.
160
AL
BE
RT
F.
BE
NN
ET
T
(see
Ben
nett
and
Daw
son,
197
6).
Fur
ther
dif
fere
ntia
tion
alo
ng e
colo
gica
l li
nes
(e.g
. spe
cies
ada
pted
to te
mpe
rate
ver
sus
trop
ical
or m
esic
ver
sus
xeri
c en
viro
nmen
ts) r
emai
ns u
nana
lyze
d an
d w
ould
see
m to
be
a w
orth
whi
le a
nd
rew
ardi
ng e
ffor
t. L
ikew
ise,
mos
t met
abol
ic o
bser
vati
ons
have
bee
n m
ade
on
rest
rict
ed s
ets
of r
epti
lian
tax
a, a
nd a
bro
ader
phy
loge
neti
c ex
amin
atio
n m
ight
als
o be
val
uabl
e in
tur
ning
up
oth
er e
nerg
etic
ada
ptat
ions
. In
any
ev
ent,
the
met
abol
ic le
vel r
epre
sent
ed b
y re
stin
g re
ptil
es (T
able
I) is
low
and
in
dist
ingu
isha
ble
from
tha
t of
oth
er e
ctot
herm
ic v
erte
brat
es o
r in
vert
e-
brat
es o
f si
mil
ar s
ize
and
tem
pera
ture
(Hem
min
gsen
, 19
60).
Alt
houg
h th
is
econ
omy
tran
slat
es i
nto
low
food
dem
ands
and
hig
h ef
fici
ency
of g
ener
atin
g ne
w b
iom
ass
(Gol
ley,
196
8; M
uell
er,
1970
; Tur
ner
et a
l.,
1976
; P
ough
, 19
80, i
n pr
ess)
, it
also
may
lim
it th
e m
axim
al l
evel
of
oxyg
en c
onsu
mpt
ion
and
cons
eque
ntly
aer
obic
ally
sus
tain
able
beh
avio
r (B
enne
tt a
nd R
uben
, 19
79).
M
any
rept
iles
und
er n
atur
al c
ondi
tion
s ar
e in
acti
ve f
or l
ong
port
ions
of
the
daily
cyc
le a
nd t
heir
rat
es o
f en
ergy
exp
endi
ture
dur
ing
thes
e ti
mes
are
cl
osel
y ap
prox
imat
ed b
y m
etab
olic
rat
es m
easu
red
at re
st in
the
labo
rato
ry.
Con
sequ
entl
y, th
ese
mai
nten
ance
met
abol
ic d
eter
min
atio
ns a
lso
have
uti
lity
in
the
est
imat
ion
of e
nerg
y ut
iliz
atio
n in
the
fie
ld.
Qui
esce
nt m
etab
olis
m
may
figu
re p
rom
inen
tly
in t
he to
tal d
aily
met
abol
ic e
xpen
ditu
re (s
ee b
elow
).
2. M
axim
al O
xyge
n C
onsu
mpt
ion
and
Aer
obic
Sco
pe
Max
imal
ox
ygen
co
nsum
ptio
n se
ts t
he u
pper
bo
unda
ry
on
aero
bic
met
abol
ism
and
con
sequ
entl
y on
sus
tain
able
lev
els
of a
ctiv
ity.
Max
imal
ae
robi
c po
wer
inp
ut c
onse
quen
tly
can
prov
ide
both
abs
olut
e an
d co
mpa
ra-
tive
info
rmat
ion
on t
he s
tam
ina
and
wor
k ca
paci
ty o
f di
ffer
ent
anim
als.
A
cons
ider
able
lit
erat
ure
has
accu
mul
ated
on
max
imal
oxy
gen
cons
umpt
ion
and
aero
bic
scop
e of
rept
iles
sin
ce th
eir
firs
t det
erm
inat
ion
by B
arth
olom
ew
and
Tuc
ker
in 1
963.
All
omet
ric
rela
tion
ship
s of
max
imal
oxy
gen
cons
ump-
ti
on w
ere
prev
ious
ly c
alcu
late
d fo
r ac
tive
rept
iles
at
30°C
(W
ilso
n, 1
974a
; B
enne
tt a
nd D
awso
n, 1
976)
. The
se c
an n
ow b
e ex
pand
ed t
o in
clud
e a
broa
der
rang
e of
bod
y te
mpe
ratu
res
and
rece
nt m
easu
rem
ents
. M
axim
al
rate
s of
oxy
gen
cons
umpt
ion
of a
ctiv
e re
ptil
es a
t 20
, 30
, 35
, and
40°
C a
re
repo
rted
in T
able
I1 a
nd th
e ex
pone
nts
of th
e al
lom
etri
c eq
uati
on M
R =
amE
ar
e gi
ven
in T
able
I11
for
liz
ards
and
for
all
rept
iles
. L
ittl
e in
terg
roup
di
ffer
enti
atio
n is
evi
dent
in
the
lim
ited
dat
a ba
se o
f T
able
11.
As
in o
ther
gr
oups
, m
axim
al a
erob
ic p
ower
inp
ut s
cale
s as
a f
ract
iona
l pow
er o
f bo
dy
mas
s th
at a
ppro
xim
ates
0.7
5 (e
xcep
t at
40°
C,
see
belo
w).
Lar
ger
anim
als
have
a g
reat
er t
otal
aer
obic
pow
er c
apac
ity
and
smal
ler
anim
als
have
a
grea
ter
mas
s-sp
ecif
ic m
axim
al o
xyge
n co
nsum
ptio
n an
d ox
ygen
del
iver
y ca
paci
ty.
Th
e ra
nge
of c
apac
itie
s of
max
imal
oxy
gen
tran
spor
t ar
e ve
ry s
imil
ar i
n
3. T
HE
ENER
GET
ICS
OF
REP
TILI
AN
ACT
IVIT
Y
TA
BL
E
TI
Max
imal
oxy
gen
cons
umpt
ion
of a
ctiv
e re
ptile
s
Spec
ies
Ref
eren
ce
Tur
tles
C
hely
dra
serp
entin
a 34
73
0.19
0.
49 - -
Gat
ten,
197
8 Ps
eude
mys
scr
ipta
30
5 0.
28
0.64
0.
85
1.03
Gat
ten,
197
4 Te
rrap
ene
orna
ta
354
0.21
0.
36
0.46
0.
73
Gat
ten,
197
4 R
hync
hoce
phal
ians
Sp
heno
don
punc
tatu
s 52
0 0.
15
0. 1
6 0.
15 -
[Vils
on a
nd L
ee,
I970
L
izar
ds
Am
blyr
hync
hus
cris
tatu
s 48
9 -
0.61
0.
80
0.75
B
enne
tt et
al.,
197
5 A
mph
ibol
urus
bar
batu
s 23
9 0.
24
0.56
0.
65
0.62
W
ilson
, l9
74b
Cne
mid
opho
rus
mur
inus
55
.2 - - -
1.63
B
enne
tt an
d G
lees
on,
1979
C
nem
idop
horu
s tig
ris
18.0
0.
41
0.90
1.
6 2.
1 A
splu
nd,
1970
D
ipso
saur
us d
orsa
lis
35.2
-
0.89
1.
64
2.45
Ben
nett
and
Daw
son,
197
2 Eg
erni
a cu
nnin
gham
i 25
7 0.
25
0.50
0.
60
0.56
W
ilson
, l9
74b
Ger
rhon
otus
mul
ticar
inat
us
24
0.30
0.
55
1.13
-
Hof
fman
n, 1
973
Igua
na i
guan
a 79
5 0.
16
0.46
0.
50
0.51
M
ober
ly,
l968
a La
cert
a sp
p.
10 -
1.49
- -
Cra
gg,
1978
Ph
ysig
nath
us l
esue
uri
549
0.23
0.
46
0.45
0.
45
[i'ils
on,
1974
b Sa
urom
alus
his
pidu
s 57
4 0.
26
0.45
0.
53
0.58
B
enne
tt, 1
972
Scel
opor
us o
ccid
enta
lis
13.1
0.
52
1.32
1.
78
1.80
Ben
nett
and
Gle
eson
, 19
76
Tiliq
ua s
cinc
oide
s 49
3 0.
14
0.24
-
0.40
B
arth
olom
en e
t al
., 1
965
Trac
hydo
saur
us r
ugos
us
421
0.24
0.
46
0.50
0.
51
Wils
on,
l974
b V
aran
us e
xant
hem
atic
us
I025
- -
1.26
-
Gle
eson
et
al.,
198
0 V
aran
us go
uldi
i 67
4 0.
32
0.57
0.
76
1.01
Ben
nett,
197
2 V
aran
us s
pp.
714
0.18
0.
37 -
0.75
B
arth
olom
ew a
nd T
ucke
r,
1964
Sn
akes
C
olub
er c
onst
rict
or,
Mas
ticop
his J
agel
lum
26
2 - -
1.02
-
Rub
en,
1976
C
rota
lus
oiri
dis
301
- -
0.52
-
Rub
en,
1976
Pi
tuop
his
cate
nife
r 54
8 0.
27
0.47
0.
52 -
Gre
enw
ald,
197
1 Sp
aler
osop
his
diad
ema
386
0.29
0.
38
0.46
0.
65 D
mi'e
l an
d B
orut
, 19
72
liza
rds
and
snak
es. T
hree
of
the
four
tur
tle
spec
ies
inve
stig
ated
(C
kely
dra,
Ps
eude
mys
, and
Che
loni
a-Ja
ckso
n an
d Pr
ange
, 19
79) h
ave
max
imal
rat
es o
f ox
ygen
con
sum
ptio
n ex
ceed
ing
pred
icte
d va
lues
. C
helo
nia,
not
nec
essa
rily
m
axim
ally
act
ive,
hav
e ae
robi
c m
etab
olic
rat
es tw
ice
thos
e pr
edic
ted
by t
he
30°C
reg
ress
ion
equa
tion
for
rep
tile
s. H
owev
er,
thei
r la
rge
size
(12
8 kg
) m
akes
sus
pect
suc
h si
ze-d
epen
dent
ext
rapo
lati
ons.
Th
e ae
robi
c ab
ilitie
s of
Sp
heno
don
at h
igh
body
tem
pera
ture
s ar
e di
stin
ctly
low
er t
han
thos
e of
ot
her
rept
iles
inv
esti
gate
d. T
his
low
aer
obic
cap
acit
y m
ay r
efle
ct a
dap-
ta
tion
s fo
r act
ivit
y at
ver
y lo
w b
ody
tem
pera
ture
s or
it m
ay p
ossi
bly
refl
ect a
re
lati
vely
slu
ggis
h ac
tivi
ty p
atte
rn f
or t
his
spec
ies,
alt
houg
h lit
tle is
kno
wn
abou
t it
s na
tura
l ac
tivi
ty.
AL
BE
RT
F.
BE
NN
ET
T
The a
llom
etri
c re
latio
nshi
p of
max
imal
oxy
gen
cons
umpt
ion
and
aero
bic
pow
er i
nput
of a
ctiv
e re
ptile
s
TB
vo
i02
--
n of
G
roup
"C
m
lOz/
h
mW
b
r sp
ecie
s
Liz
ards
20
0.
69
3.9
0.81
0.
78
12
30
1.96
11
.0
0.76
0.
82
15
35
2.92
16
.3
0.76
0.
56
13
40
5.86
32
.8
0.64
0.
86
14
All
rept
iles
20
0.65
3.
6 0.
83
0.72
18
30
1.
78
10.0
0.
77
0.71
21
35
3.
43
19.2
0.
71
0.66
20
40
5.
87
32.8
0.
64
0.85
17
Dat
a ar
e gi
ven
in T
able
11.
M
ass
is in
g.
TR
=bod
y te
mpe
ratu
re.
Aer
obic
cap
acit
y is
exp
ress
ed
eith
er a
s ae
robi
c m
etab
olic
sco
pe,
the
diff
eren
ce b
etw
een
max
imal
and
res
ting
oxy
gen
cons
umpt
ion,
or a
s the
rati
o of
thes
e tw
o qu
anti
ties
, ter
med
eit
her t
he in
dex
ofm
etab
olic
exp
ansi
bili
ty o
r th
e m
axim
al f
acto
rial
inc
rem
ent.
Th
e m
ass-
depe
nden
t ex
pone
nt o
f re
stin
g an
d m
axim
al o
xyge
n co
nsum
ptio
n is
sim
ilar
(ap
prox
imat
ely
m0.
75) at
20,
30,
and
35°C
(T
able
I a
nd 1
11).
Thu
s, a
erob
ic s
cope
sca
les
with
mas
s to
the
sa
me
degr
ee (m
0.75
). The
se m
ass-
spec
ific
val
ues a
re e
quiv
alen
t to
thos
e fo
und
for
mam
mal
s (L
echn
er,
1978
; Tay
lor
et a
l., 1
978)
and
bir
ds (
Ber
ger
et a
l.,
1970
). H
owev
er, a
s re
ptil
ian
body
siz
e in
crea
ses,
max
imal
oxy
gen
cons
ump-
ti
on a
t 40°
C d
oes n
ot in
crea
se to
the
sam
e de
gree
as
does
that
at r
est (
6=0.
64
and
0.79
for
act
ivit
y an
d re
st r
espe
ctiv
ely)
. C
onse
quen
tly,
aer
obic
sco
pe
scal
es to
onl
y m
O.h
and
the
fact
oria
l inc
rem
ent d
ecli
nes
with
incr
easi
ng b
ody
size
. At 4
0°C
, a 1
0-g
lizar
d ca
n in
crea
se it
s ox
ygen
con
sum
ptio
n to
7.2
tim
es
rest
ing
leve
ls,
but
a 1-
kg l
izar
d, c
an o
nly
incr
ease
it
to 3
.6 a
nd m
axim
al
valu
es a
re o
nly
one-
half
ant
icip
ated
lev
els
(Fig
. 2)
. T
hese
rel
atio
nshi
ps
mig
ht s
ugge
st t
hat
larg
e re
ptil
es a
t hi
gh b
ody
tem
pera
ture
s m
ight
fin
d it
di
ffic
ult t
o p
rocu
re s
uffi
cien
t oxy
gen
to s
uppo
rt a
ctiv
ity. H
owev
er, m
any
of
the
spec
ies
of la
rger
ani
mal
s lis
ted
in T
able
I1
appe
ar t
o m
axim
ize
aero
bic
scop
e at
thei
r m
ean
sele
cted
bod
y te
mpe
ratu
res.
The
se a
re g
ener
ally
bel
ow
40°C
. T
his
rel
atio
nshi
p m
ay t
hus
be a
n ad
apta
tion
to
prom
ote
max
imal
ae
robi
c w
ork
capa
city
at n
orm
al b
ody
tem
pera
ture
s an
d m
ay n
ot re
pres
ent a
fa
ilur
e of
tran
spor
t ca
paci
ties
per
se. A
t any
rat
e, a
t hig
h te
mpe
ratu
res
som
e
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
10
100
1000
Moss
(g
)
FIG
. 2. P
redi
cted
rel
atio
nshi
ps o
f re
stin
g an
d m
axim
al o
xyge
n co
nsum
ptio
n of
liza
rds
as a
func
tion
of
body
mas
s an
d te
mpe
ratu
re.
Dat
a fr
om T
able
s I
and
111.
larg
er r
epti
les
do
not
inc
reas
e ox
ygen
con
sum
ptio
n as
muc
h as
they
can
at
low
er
tem
pera
ture
s.
Smal
ler
rept
iles
do
not
se
em
to
expe
rien
ce t
his
lim
itat
ion.
A
llom
etri
c an
alys
es a
re u
sefu
l fo
r ex
amin
ing
the
func
tion
al c
apac
ities
of
grou
ps o
f an
imal
s or
for
pre
dict
ing
the
func
tion
al l
evel
of
pre
viou
sly
unin
vest
igat
ed s
peci
es.
How
ever
, th
ey o
bscu
re r
eal
inte
rspe
cifi
c va
riat
ion.
R
epti
les
of s
imil
ar b
ody
size
may
dif
fer
grea
tly
in t
heir
cap
aciti
es to
supp
ort
aero
bic
acti
vity
. F
or i
nsta
nce,
max
imal
oxy
gen
cons
umpt
ion
may
var
y at
le
ast
four
fold
am
ong
diff
eren
t sp
ecie
s of
sna
kes
of s
imil
ar s
ize
and
body
te
mpe
ratu
re (
Tab
le IV
). S
nake
s th
at a
re c
apab
le o
f in
tens
e an
d pr
olon
ged
stru
ggli
ng, s
uch
as C
olub
er a
nd M
astic
ophi
s, s
usta
in g
reat
er le
vels
of a
erob
ic
tran
spor
t th
an d
o m
ore
mod
erat
ely
activ
e (~
Ver
odia
, Pitu
ophi
s) o
r sl
uggi
sh
(Lic
hanu
ra)
anim
als
(Rub
en,
1976
). T
ucke
r (1
967)
firs
t not
ed th
e as
soci
ated
of
hig
h ca
paci
ties
for
act
ivity
and
rap
id f
light
with
hig
h ae
robi
c sc
ope
in
som
e sp
ecie
s an
d th
e co
rrel
atio
n be
twee
n st
atic
def
ense
pos
ture
s, l
ow
acti
vity
cap
acit
y, a
nd lo
w a
erob
ic s
cope
in o
ther
s. A
s ex
ampl
es h
e no
ted
the
164
AL
BE
RT
F.
BE
NN
ET
T
Max
imal
aer
obic
pow
er i
nput
of s
ever
al s
peci
es o
f sna
kes
Spec
ies
Col
uber
con
stri
ctor
, il
.last
icop
his~
agel
lum
C
ruta
lus
niri
dis
L~ch
anur
a tri
virg
ata
Ner
odia
rhn
mbi
fera
Pitu
ophi
s m
elan
oleu
cus
Spal
eros
ophi
s di
adem
a
Aer
obic
pow
er
Mas
s T
B
inpu
t --
Ref
eren
ce
-
Rub
en,
1976
Rub
en,
1976
R
uben
, 19
76
Gra
tz a
nd H
utch
ison
, 19
77
Gre
enw
ald,
197
1 D
mi'e
l an
d B
orut
, 19
72
TB
= bo
dy t
empe
ratu
re
liza
rds
Var
anus
, Igu
ana,
Am
phib
olur
us, a
nd T
iliqu
a, w
hich
wer
e co
nsid
ered
to
for
m a
n ac
tivity
ser
ies
sim
ilar
to t
hat
note
d pr
evio
usly
for
the
spe
cies
of
snak
es. T
he
capa
city
for s
usta
ined
act
ivity
am
ong
rept
iles
und
er e
xper
imen
- ta
l co
ndit
ions
app
ears
to
be w
ell
refl
ecte
d in
and
dir
ectl
y co
rrel
ated
with
ae
robi
c sc
ope
and
max
imal
oxy
gen
cons
umpt
ion.
In
add
itio
n to
bod
y te
mpe
ratu
re,
mas
s, a
nd p
hylo
gene
tic
affi
nity
, oth
er
fact
ors
also
inf
luen
ce m
axim
al l
evel
s of
aer
otic
met
abol
ism
. F
or i
nsta
nce,
th
e st
ate
of t
herm
al a
cclim
atio
n ha
s be
en s
how
n to
inf
luen
ce m
axim
al
oxyg
en
cons
umpt
ion
of s
napp
ing
turt
les
(Che
lydr
a se
rpen
tina;
Gat
ten,
19
78).
Tur
tles
acc
limat
ed a
t 10
°C d
o no
t at
tain
leve
ls o
f ox
ygen
con
sum
p-
tion
of
thos
e ac
clim
ated
at 2
S°C
, eve
n w
hen
both
are
mea
sure
d at
the
sam
e te
st t
empe
ratu
res.
In
the
sin
gle
stud
y on
the
topi
c, n
o in
flue
nce
of t
ime
of
day
on m
axim
al o
xyge
n co
nsum
ptio
n w
as f
ound
for
the
sna
ke N
erod
ia
vhow
zblfe
ra (
Gra
tz a
nd H
utch
ison
, 19
77).
Mor
e de
tail
ed s
tudi
es o
n su
ch
fact
ors
are
requ
ired
bef
ore
it is
pos
sibl
e to
mak
e an
y so
rt o
f sa
tisf
acto
ry
gene
rali
zati
on r
egar
ding
the
infl
uenc
es t
hat
affe
ct m
axim
al l
evel
s of
aer
obic
m
etab
olis
m i
n re
ptil
es.
3. B
od
j~ Tem
pera
ture
and
Oxy
gen
Con
sum
ptio
n B
ody
tem
pera
ture
has
a p
rono
unce
d ef
fect
on
the
rate
of
oxyg
en u
ptak
e (F
ig.
1; T
able
s I
and
111)
, as t
he re
stin
g m
etab
olic
rate
s of
rept
iles
tend
to b
e st
rong
ly t
herm
ally
dep
ende
nt (
Daw
son,
196
7; T
empl
eton
, 19
70; B
enne
tt
and
Daw
son,
197
6). L
ow t
empe
ratu
res
redu
ce a
erob
ic e
nerg
y ut
iliz
atio
n.
Th
e ge
nera
lized
rel
atio
nshi
ps o
f m
axim
al o
xyge
n co
nsum
ptio
n an
d bo
dy
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
16
5
size
ind
icat
e th
at m
axim
al o
xyge
n tr
ansp
ort
has
a te
mpe
ratu
re c
oeff
icie
nt
(Qlo
) of
2.0-
2.5
betw
een
20 a
nd 3
5°C
for
liza
rds
of a
ll bo
dy s
izes
(Tab
le V
). T
hat
is,
aer
obic
pow
er i
nput
dur
ing
activ
ity i
ncre
ases
tw
o or
mor
e tim
es
whe
n bo
dy
tem
pera
ture
in
crea
ses
10°C
. Sm
all
liza
rds
mai
ntai
n th
is
rela
tion
ship
at
35
4O0C
, bu
t in
la
rger
an
imal
s th
e m
axim
al
oxyg
en
cons
umpt
ion
over
th
is
rang
e is
ne
arly
in
depe
nden
t of
te
mpe
ratu
re
(Qo"
1.
0).
Th
e th
erm
al d
epen
denc
e of
max
imal
oxy
gen
cons
umpt
ion
impo
ses
cons
trai
nts
on s
tam
ina
and
pow
er i
nput
for
ani
mal
s th
at u
nder
go
daily
th
erm
al
cycl
es a
nd m
ust
star
t m
orni
ng
activ
ity
with
lo
w
body
te
mpe
ratu
res.
Th
is t
herm
al d
epen
denc
e ha
s ev
en m
ore
impo
rtan
t co
nse-
qu
ence
s fo
r an
imal
s th
at a
re n
orm
ally
act
ive
at l
ow b
ody
tem
pera
ture
s.
The
se c
onse
quen
ces
are
disc
usse
d in
Sec
tion
11.
C.
2.
For
man
y li
zard
s, m
axim
al o
xyge
n co
nsum
ptio
n (
Qo
z 1.
0) b
ecom
es
inde
pend
ent
of t
empe
ratu
re a
t bo
dy t
empe
ratu
res
exce
edin
g no
rmal
ly
pref
erre
d or
mai
ntai
ned
leve
ls (
Wil
son,
197
4b).
Th
at is
, max
imum
oxy
gen
cons
umpt
ion
incr
ease
s w
ith a
ntic
ipat
ed t
herm
al d
epen
denc
e up
to
pre-
fe
rred
bod
y te
mpe
ratu
re a
nd th
en r
emai
ns c
onst
ant u
p to
dam
agin
g th
erm
al
leve
ls (
see,
for
exa
mpl
e, F
ig.
1). A
nim
als
in w
hich
suc
h co
nsta
nt le
vels
hav
e be
en
repo
rted
in
clud
e A
mbl
yrh.
ynch
us
cris
tatu
s (B
enne
tt e
t al
., 19
75),
Am
phib
olur
us b
arba
tus,
Ege
rnia
cu
nnin
gham
i, Ph
.ysi
gnat
hus
lesu
euri
, an
d T
rach
ydos
auru
s ru
gosu
s (W
ilso
n, 1
974b
), D
ipso
saur
us d
orsa
lis (B
enne
tt an
d D
awso
n,
1972
), I
guan
a ig
uana
(M
ober
ly,
1968
a),
Saur
otna
lus
hisp
idm
(B
enne
tt,
1972
), an
d Sc
elop
orus
occ
iden
talis
(B
enne
tt a
nd G
lees
on,
1976
). T
his
att
ainm
ent o
f m
axim
al o
xyge
n co
nsum
ptio
n at
sel
ecte
d th
erm
al le
vels
re
sult
s in
a m
axim
al a
erob
ic s
cope
(an
d pr
esum
ably
aer
obic
wor
k ca
paci
ty)
at th
ese
tem
pera
ture
s. A
t hig
her
tem
pera
ture
s, re
stin
g ox
ygen
con
sum
ptio
n co
ntin
ues
to in
crea
se a
nd th
e di
ffer
ence
bet
wee
n th
ese
fact
ors
cons
eque
ntly
The
tem
pera
ture
de
pend
ence
of
max
imal
~
erob
ir
pow
er i
nput
of l
izar
ds.
Mas
s a
o
-
Dat
a ar
e ta
ken
from
reg
ress
ion
equa
tions
in T
able
11
1.
166
AI.
BE
RT
F.
BE
NN
ET
T
decl
ines
. S
uch
coin
cide
nce
of m
axim
al f
unct
iona
l cap
acity
and
exp
erie
nced
th
erm
al le
vel i
s at
firs
t gla
nce
rath
er p
leas
ing,
as
it su
gges
ts th
at a
nim
als m
ay
be a
dapt
ed t
o fu
ncti
on b
est
unde
r th
e co
ndit
ions
they
nor
mal
ly e
xper
ienc
e.
Th
is w
as a
lso
the
ther
mal
pat
tern
of
wor
k ca
paci
ty p
redi
cted
and
des
crib
ed
for
fish
(F
ry,
1947
).
How
ever
, m
any
othe
r sp
ecie
s of
re
ptil
es
do
not
co
nfor
m
to
this
re
lati
onsh
ip; t
heir
max
imal
oxy
gen
cons
umpt
ion
cont
inue
s to
incr
ease
up
to
the
high
est
body
tem
pera
ture
s m
easu
red.
The
se s
peci
es in
clud
e th
e liz
ards
E
umec
es
obso
letu
s (A
. F
. B
enne
tt
and
W.
R.
Daw
son,
un
publ
ishe
d),
Ger
rhon
otus
muf
ticar
inat
us (
Hof
fman
n, 1
973)
, and
Tif
iqua
sci
ncoi
des
(Bar
- th
olom
ew e
t al.,
196
.5);
the
snak
es P
ituop
his
mel
anol
eucu
s (G
reen
wal
d, 1
97 1)
an
d Sp
aler
osop
his d
iade
ma
clzf
irdi
(D
mi'e
l an
d B
orut
, 19
72);
the
rhyn
cho-
ce
phal
ian
Splz
enod
on p
unct
atus
(W
ilson
and
Lee
, 19
70);
and
the
tur
tles
Ps
eude
mys
scr
ipta
and
Ter
rape
ne o
rnat
a (G
atte
n, 1
974)
. In
thes
e sp
ecie
s,
max
imal
oxy
gen
cons
umpt
ion
cont
inue
s to
inc
reas
e in
par
alle
l to
bod
y te
mpe
ratu
re u
p to
let
hal
leve
ls.
Con
sequ
entl
y ae
robi
c sc
ope
and
wor
k ca
paci
ty a
re n
ot m
axim
ized
at f
ield
-act
ive
body
tem
pera
ture
s. R
athe
r, th
ese
func
tion
s ar
e op
tim
ized
at b
ody
tem
pera
ture
s th
at a
re ra
rely
if e
ver a
ttain
ed
unde
r na
tura
l co
ndit
ions
. N
orm
ally
act
ive
body
tem
pera
ture
s of
Cne
mid
o-
phor
us (
Asp
lund
, 19
70)
and
Var
anus
(B
arth
olom
ew a
nd T
ucke
r,
1964
; B
enne
tt,
1972
) are
so
clos
e to
dam
agin
g th
erm
al le
vels
tha
t it
has
not
been
po
ssib
le t
o di
scri
min
ate
whi
ch p
atte
rn t
hese
ani
mal
s fo
llow
. A
n ex
amin
atio
n of
the
spe
cies
in
each
cat
egor
y re
veal
s an
int
eres
ting
ph
ylog
enet
ic r
elat
ions
hip.
Th
e sp
ecie
s w
hich
opt
imiz
e ae
robi
c fu
ncti
on a
t pr
efer
red
ther
mal
leve
ls a
re, w
ith tw
o ex
cept
ions
, igu
anid
or a
gam
id li
zard
s;
no ig
uani
ds o
r aga
mid
s exa
min
ed fa
il to
show
this
max
imiz
atio
n. A
mon
g th
e sk
inks
, tw
o sp
ecie
s (E
gern
ia c
unni
ngha
mi,
Tra
chyd
osau
rus
rugo
sus)
rea
ch
stea
dy m
axim
al o
xyge
n co
nsum
ptio
n an
d tw
o d
o n
ot (
Eum
eces
obs
olet
us,
Tili
qua
scin
coid
es).
In c
ontr
ast,
the
max
imal
oxy
gen
cons
umpt
ion
of o
ther
fa
mili
es o
f li
zard
s an
d ot
her
grou
ps o
f re
ptil
es s
how
s a
stri
ct t
herm
al
depe
nden
ce.
The
rmal
dep
ende
nce
is m
ore
phyl
ogen
etic
ally
wid
espr
ead
amon
g re
ptil
es a
nd i
s in
con
form
ity
with
ant
icip
ated
the
rmal
eff
ects
on
biol
ogic
al r
ate
proc
esse
s. I
t is
rea
sona
ble
to a
ssum
e th
at t
he c
ondi
tion
in
igua
nid
and
agam
id l
izar
ds,
whi
ch b
elon
g to
clo
sely
rel
ated
fam
ilies
, is
a
late
r de
riva
tion
and
rep
rese
nts
a sp
ecif
ic a
dapt
atio
n in
the
ir s
yste
ms
of
oxyg
en t
rans
port
and
con
sum
ptio
n. T
he
adva
ntag
e of
max
imiz
ing
aero
bic
wor
k ab
ility
at
body
tem
pera
ture
s th
at a
re e
xper
ienc
ed n
orm
ally
are
cle
ar.
Th
e fa
ilur
e of
oth
er g
roup
s to
do
so is
mor
e pu
zzli
ng. F
or w
hate
ver
sele
ctiv
e re
ason
s, t
he p
rese
nt d
ata
indi
cate
tha
t th
e th
erm
al d
epen
denc
e of
aer
obic
tr
ansp
ort
in i
guan
id a
nd a
gam
id l
izar
ds is
dif
fere
nt f
rom
that
of
mos
t ot
her
rept
iles
. Con
sequ
entl
y, c
are
shou
ld b
e ta
ken
in g
ener
aliz
ing
data
fro
m th
ese
grou
ps to
a b
road
er r
epti
lian
con
text
. It
is s
omew
hat u
nfor
tuna
te t
hat m
ost
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
16
7
data
reg
ardi
ng a
ctiv
ity
ener
geti
cs d
eriv
e fr
om t
hese
met
abol
ical
ly a
typi
cal
form
s.
Suc
h re
gula
tion
of
bo
dy
tem
pera
ture
as
oc
curs
am
ong
rept
iles,
is
ge
nera
lly a
ccom
plis
hed
by b
ehav
iour
al r
athe
r th
an b
y m
etab
olic
mea
ns
(Ave
ry,
Bar
thol
omew
an
d H
uey,
vol
ume
12). H
owev
er,
unde
r ce
rtai
n th
erm
oreg
ulat
ory
circ
umst
ance
s, r
eptil
es d
o in
crea
se o
xyge
n co
nsum
ptio
n an
d he
at
prod
ucti
on.
Met
abol
ic
rate
s ar
e gr
eate
r in
so
me
anim
als
expe
rien
cing
a d
ecli
ne i
n bo
dy t
empe
ratu
re t
han
they
are
in
the
sam
e an
imal
s w
hen
body
tem
pera
ture
is
incr
easi
ng (
Alli
gato
r, S
mit
h,
1975
; A
mbf
yrh~
~nch
us, Bar
thol
omew
and
Vle
ck,
1979
; Spa
lero
soph
is, D
mi'e
l an
d B
orut
, 19
72).
Th
e re
sult
ing
heat
pro
duct
ion
may
del
ay c
oolin
g an
d m
aint
ain
high
er t
empe
ratu
res
for
long
er p
erio
ds o
f ti
me,
pre
sum
ably
inc
reas
ing
the
activ
e pe
riod
und
er n
atur
al c
oolin
g co
ndit
ions
. T
he
mec
hani
sm o
f th
is
ther
mog
enes
is is
pre
sum
ed t
o be
incr
ease
d m
uscu
lar a
ctiv
ity.
In c
ontr
ast t
o th
is m
etab
olic
res
pons
e to
tran
sien
t the
rmal
con
diti
ons,
met
abol
ic th
erm
o-
gene
sis
mai
ntai
ning
a b
ody
tem
pera
ture
abo
ve a
mbi
ent (
i.e. t
he c
ondi
tion
of
endo
ther
my)
is a
ppar
entl
y ra
re in
rep
tiles
. Th
e o
nly
wel
l-do
cum
ente
d ca
se
is t
hat
of in
cuba
ting
fem
ale
pyth
ons
(Hut
chis
on e
t al.,
196
6; V
ineg
ar e
t al.,
19
70).
Seve
ral s
peci
es o
f the
se s
nake
s m
aint
ain
body
and
egg
tem
pera
ture
as
muc
h as
5-6
°C
abov
e am
bien
t te
mpe
ratu
re b
y sp
asm
odic
con
trac
tions
of
thei
r bo
dy m
uscu
latu
re.
Th
is t
herm
oreg
ulat
ory
activ
ity i
s ex
pens
ive
and
incr
ease
s ox
ygen
con
sum
ptio
n as
muc
h as
tenf
old
abov
e re
stin
g le
vels
.
1. E
Ject
of T
rain
ing
on A
erob
ic A
bilit
y C
erta
in m
amm
als
may
m
odif
y th
eir
capa
city
fo
r m
axim
al
aero
bic
perf
orm
ance
and
ox
ygen
co
nsum
ptio
n by
pr
ior
phys
ical
co
nditi
onin
g (E
kblo
m,
1969
; Hol
losz
y, 1
973)
. Th
e ex
tent
to w
hich
rept
ilian
per
form
ance
is
inf
luen
ced
by s
imil
ar c
ondi
tion
ing
or i
nact
ivity
has
bee
n lit
tle i
nves
ti-
gate
d. A
s re
ptil
es a
re o
ften
mai
ntai
ned
in la
bora
tori
es fo
r a v
aria
ble
leng
th o
f ti
me
befo
re m
etab
olic
ana
lysi
s, t
he d
egre
e to
whi
ch p
erfo
rman
ce is
alte
red
by t
his
inac
tivi
ty i
s a
mat
ter
of c
once
rn.
A s
ingl
e st
udy
(Gle
eson
, 19
79a)
fo
und
no
sig
nifi
cant
eff
ect
of tr
aini
ng o
n pe
rfor
man
ce o
r ox
ygen
tra
nspo
rt
abili
ty i
n th
e li
zard
Sce
lopo
rus
occi
dent
alis
. M
axim
al a
erob
ic a
bilit
y w
as
unch
ange
d by
6-8
w
eeks
of
daily
phy
sica
l ac
tivity
or
by a
sim
ilar
peri
od o
f in
acti
vity
in
com
pari
son
with
tha
t of
ani
mal
s re
cent
ly r
emov
ed f
rom
the
fi
eld.
The
se l
izar
ds w
ere
cons
eque
ntly
ch
arac
teri
zed
as "
met
abol
ical
ly
infl
exib
le,"
ind
icat
ing
that
, unl
ike
mam
mal
s in
vest
igat
ed, a
erob
ic m
etab
olic
sy
stem
s d
o n
ot s
eem
infl
uenc
ed b
y th
e de
gree
of p
rior
phy
sica
l ac
tivity
. Th
e be
havi
or o
f the
se li
zard
s is
cha
ract
eriz
ed b
y sh
ort b
urst
s of
act
ivity
and
littl
e su
stai
ned
exer
tion
. C
ompa
rabl
e st
udie
s on
rep
tile
s th
at e
ngag
e in
lon
ger
bout
s of
ae
robi
cally
su
ppor
ted
activ
ity
wou
ld
indi
cate
w
heth
er
this
m
etab
olic
inf
lexi
bilit
y is
cha
ract
eris
tic
of t
he e
ntir
e gr
oup.
168
AL
BE
RT
F.
BE
NN
ET
T
1. G
ener
al
Res
ting
and
max
imal
lev
els
of o
xyge
n co
nsum
ptio
n pr
esen
t bo
unda
ry
cond
itio
ns w
ithi
n w
hich
aer
obic
met
abol
ism
can
be
supp
orte
d. A
s an
anim
al
beco
mes
ac
tive
and
its
leve
l of
act
ivity
in
crea
ses,
so
will
it
s ox
ygen
co
nsum
ptio
n. T
he
quan
tita
tive
rel
atio
nshi
p be
twee
n ox
ygen
con
sum
ptio
n an
d pe
rfor
man
ce l
evel
cha
ract
eriz
es t
he c
ost
of l
ocom
otio
n, a
nd m
uch
rece
nt s
tudy
has
bee
n de
vote
d to
the
quan
tifi
cati
on o
f loc
omot
ory
ener
geti
cs
over
the
ran
ge o
f su
stai
nabl
e le
vels
of
exer
tion
. A
t so
me
exer
cise
lev
el,
max
imal
oxy
gen
cons
umpt
ion
is a
ttai
ned.
Eve
n th
ough
wor
k ou
tput
may
in
crea
se f
urth
er,
the
max
imal
aer
obic
pow
er i
nput
rem
ains
con
stan
t an
d ad
diti
onal
, no
n-su
stai
nabl
e m
etab
olic
su
ppor
t ha
s to
be
prov
ided
. In
re
ptil
es t
his
tran
siti
on p
oint
occ
urs
at r
athe
r lo
w w
ork
leve
ls; c
onse
quen
tly
thes
e an
imal
s can
not s
uppo
rt o
r su
stai
n vi
goro
us a
ctiv
ity b
y ae
robi
c m
eans
. T
he
poin
t of
tra
nsit
ion
from
aer
obic
to
anae
robi
c m
etab
olis
m p
rovi
des
a go
od i
ndic
ator
of
phys
iolo
gica
l li
mit
atio
n on
rep
tili
an b
ehav
iora
l pa
tter
ns.
2. E
nerg
etic
s of
Wal
king
and
Run
ning
T
he
loco
mot
ory
ener
geti
cs o
f ter
rest
rial
rep
tile
s ha
ve b
een
dete
rmin
ed in
an
imal
s w
alki
ng o
n m
otor
-dri
ven
trea
dmil
ls o
ver a
rang
e of
spe
eds.
Rat
es o
f ox
ygen
co
nsum
ptio
n ar
e de
term
ined
sim
ulta
neou
sly,
ac
cord
ing
to t
he
patt
ern
esta
blis
hed
for
com
para
tive
mam
mal
ian
stud
ies
(Tay
lor
et a
l.,
1970
). N
umer
ous
stud
ies
of th
is ty
pe s
how
that
aer
obic
pow
er i
nput
dur
ing
wal
king
inc
reas
es l
inea
rly
with
sp
eed
up
to
max
imal
lev
els
of o
xyge
n co
nsum
ptio
n.
Suc
h a
rela
tion
ship
is
sh
own
in
Fig.
3
for
Var
anus
ex
anth
emat
icus
(da
ta f
rom
Gle
eson
et
al.,
1980
), in
whi
ch t
he t
erm
inol
ogy
asso
ciat
ed w
ith l
ocom
otor
y en
erge
tics
is a
lso
indi
cate
d. A
line
ar e
xtra
pola
- tio
n of
the
rat
e of
oxy
gen
cons
umpt
ion
at z
ero
spee
d (t
he Y
-int
erce
pt,
Schm
idt-
Nie
lsen
, 19
72) i
s 1.
5-2.
0 ti
mes
res
ting
leve
ls a
nd is
ass
umed
to
be
asso
ciat
ed w
ith p
ostu
ral
adju
stm
ents
ass
ocia
ted
with
act
ivity
(S
chm
idt-
N
iels
en,
1972
). T
he
mas
s-sp
ecif
ic a
erob
ic p
ower
inpu
t div
ided
by
the
spee
d of
loco
mot
ion
is te
rmed
the
cos
t of
tran
spor
t (T
ucke
r, 1
970)
or
the
tota
l cos
t of
loco
mot
ion
(Sch
mid
t-N
iels
en,
1972
). I
t is
the
amou
nt o
f ene
rgy
expe
nded
to
mov
e a
unit
mas
s ov
er a
uni
t di
stan
ce a
nd is
mea
sure
d as
joul
es,
calo
ries
, or
mil
lili
ters
of
oxyg
en p
er (
gram
x k
ilom
eter
). T
his
is
the
actu
al c
ost
incu
rred
by
a m
ovin
g an
imal
and
is
usef
ul i
n es
tim
atin
g th
e re
al c
ost
of
mov
emen
ts,
such
as
thos
e as
soci
ated
with
fe
edin
g, c
ourt
ship
, in
tim
e-
ener
gy b
udge
ts o
f ani
mal
s. I
t has
a c
onsi
dera
ble
com
pone
nt a
ssoc
iate
d w
ith
mai
nten
ance
m
etab
olis
m
and
is
also
sp
eed
depe
nden
t.
For
st
udie
s in
vest
igat
ing
loco
mot
ory
ener
geti
cs p
er s
e, t
he p
resu
mpt
ive
mai
nten
ance
an
d po
stur
al c
ompo
nent
s ar
e re
mov
ed b
y su
btra
ctin
g th
ese
cost
s (e
qual
to
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
16
9
-Max
imal
0-
0 0-
oxyg
en c
onsu
mpt
ion
A "0
2 =
Net
co
st o
f tr
ansp
ort
A s
peed
'
Y-
inte
rcep
t
! -Res
t 'C
ost
of
Max
imal
Ir
ansp
ort
at
aero
bic
0.5
km
/h
spee
d
i I
I I
0 5
1.
0 1.
5 2.
0 I
km/h
FIG.
3. V
aran
us e
xanr
hem
aric
us. O
xyge
n co
nsum
ptio
n as
a fu
nctio
n of
wal
king
spee
d at
35°
C. D
ata
from
G
lees
on e
t al
. (1980b). L
ocom
otor
y te
rmin
olog
y is
illu
stra
ted
on t
he f
igur
e.
the
Y-i
nter
cept
) fr
om t
he m
etab
olic
exp
endi
ture
and
obt
aini
ng th
e ne
t cos
t of
tran
spor
t. T
his
is
effe
ctiv
ely
the
slop
e of
oxy
gen
cons
umpt
ion
as a
fu
ncti
on o
f sp
eed
(Sch
mid
t-N
iels
en,
1972
). T
his
num
ber
is in
depe
nden
t of
spee
d tr
avel
ed. T
he
aero
bic
pow
er i
nput
req
uire
d fo
r m
ovem
ent a
t a g
iven
sp
eed
may
be
appr
oxim
ated
by
addi
ng t
he p
rodu
ct o
f th
e ne
t co
st o
f tr
ansp
ort
and
the
spee
d to
1.7
tim
es t
he r
esti
ng
oxyg
en c
onsu
mpt
ion
(Tay
lor,
197
3). O
xyge
n co
nsum
ptio
n co
ntin
ues
to ri
se t
o m
axim
al v
alue
s an
d th
en re
mai
ns c
onst
ant a
s sp
eed
incr
ease
s. T
his
tran
siti
on is
her
e te
rmed
th
e m
axim
al a
erob
ic s
peed
. As
pow
er r
equi
rem
ents
do
not
inc
reas
e lin
earl
y w
ith
spee
d in
sw
imm
ing
orga
nism
s, l
ocom
otor
y en
erge
tics
are
gen
eral
ly
anal
yzed
onl
y as
the
tota
l co
st o
f tr
ansp
ort
or l
ocom
otio
n.
Liz
ards
are
the
only
rept
ilia
n gr
oup
for w
hich
loco
mot
ory
ener
getic
s ha
ve
been
an
alyz
ed
in
suff
icie
nt d
etai
l to
per
mit
pa
rtia
l ge
nera
lizat
ion
and
anal
ysis
of
data
(M
ober
ly,
1968
b; B
akke
r,
1972
; D
mi'e
l an
d R
appe
port
, 19
76; C
ragg
, 197
8; G
lees
on,
1979
b; B
enne
tt a
nd G
lees
on,
1979
; Joh
n-A
lder
an
d B
enne
tt,
1981
). B
ased
on
a re
cent
ana
lysi
s (G
lees
on,
1979
b), t
he n
et c
ost
of t
rans
port
for
thes
e an
imal
s as
a f
unct
ion
of b
ody
size
is p
rese
nted
in
Fig.
4.
Th
e co
st d
ecre
ases
with
inc
reas
ing
body
siz
e ac
cord
ing
to t
he r
elat
ion
Net
cos
t of
tra
nspo
rt =
3.7
7 ~
t-
~.
~~
whe
re n
et c
ost o
f tr
ansp
ort
is m
easu
red
in m
l O
z/(g
- km
) an
d m i
s m
ass
in g
(n
= 2
8, r
=0.
87).
Con
sequ
entl
y, it
is le
ss e
xpen
sive
for a
larg
e liz
ard
to m
ove
a un
it o
f it
s m
ass
over
a g
iven
dis
tanc
e th
an i
t is
for
a s
mal
ler
lizar
d.
170
AL
BE
RT
F.
BE
NN
ET
T
How
ever
, the
tota
l loc
omot
ory
cost
is g
reat
er f
or a
larg
er a
nim
al, a
s it
mus
t m
ove
a gr
eate
r m
ass.
Sim
ilar
mas
s-de
pend
ent
rela
tions
hips
occ
ur d
urin
g te
rres
tria
l lo
com
otio
n in
mam
mal
s (T
aylo
r et
al.,
197
0; S
chm
idt-
Nie
lsen
, 19
72).
Th
e da
ta in
Fig
. 4 sh
ow c
onsi
dera
ble
vari
atio
n, n
ot a
ll of
whi
ch m
ay
be a
ttri
buta
ble
to d
iffe
rent
met
hodo
logi
es.
For
ins
tanc
e, t
he l
ocom
otor
y co
sts
of I
guan
a (M
ober
ly,
1968
b; G
lees
on e
t al
., 19
80)
are
cons
iste
ntly
ne
arly
tw
ice
thos
e of
oth
er l
izar
ds o
f si
mila
r si
ze,
incl
udin
g th
e ot
her
igua
nids
Am
blyr
hync
hus
and
Con
olop
hus.
Th
e ac
cum
ulat
ion
of m
ore
data
m
ay p
erm
it a
fin
er a
naly
sis
of in
ters
peci
fic
diff
eren
ces
in l
ocom
otor
y co
sts.
A
n in
tere
stin
g co
mpa
rativ
e ob
serv
atio
n is
the
add
ition
al d
eter
min
atio
n of
th
e lo
com
otor
y en
erge
tics
of a
gar
ter
snak
e (T
ham
noph
is s
irta
lis;
Cho
drow
an
d T
aylo
r, 1
973)
. T
he
net
cost
of
tran
spor
t [0
.52
ml
02/(
g.km
), 2
4 g
snak
es]
is o
nly
31%
tha
t an
tici
pate
d fo
r a
lizar
d of
sim
ilar
size
. L
imbl
ess
loco
mot
ion
may
th
us
be
muc
h m
ore
econ
omic
al
than
qu
adru
peda
l,
prob
ably
bec
ause
of
the
elim
inat
ion
of a
nti-
grav
itatio
nal
supp
ort
and
the
lack
of v
ertic
al d
ispl
acem
ent o
f the
cen
ter o
f mas
s. T
his
may
be
an e
nerg
etic
co
nsid
erat
ion
invo
lved
in
the
freq
uent
ind
epen
dent
evo
lutio
n of
rep
tilia
n gr
oups
with
gre
atly
red
uced
lim
bs.
Th
e en
erge
tic c
ost o
f lo
com
otio
n is
, of
cour
se,
only
one
fac
tor
infl
uenc
ing
the
evol
utio
n of
a lo
com
otor
y m
ode.
T
he
infl
uenc
e of
bod
y te
mpe
ratu
re o
n re
ptili
an l
ocom
otor
y co
sts
have
be
en m
easu
red
in o
nly
thre
e sp
ecie
s of
liz
ards
: Ig
uana
(M
ober
ly,
1968
b),
Uro
mas
tyx
(Dm
i'el
and
Rap
pepo
rt,
1976
), an
d D
ipso
saur
us (J
ohn-
Ald
er
and
Ben
nett
, 19
81).
Dif
fere
nt p
atte
rns
of t
empe
ratu
re i
nflu
ence
hav
e be
en
obse
rved
. In
Uro
mas
tyx,
the
cos
t of
tra
nspo
rt (
mea
sure
d as
tot
al o
xyge
n
I
I
Il
l
I I
I
ll
I
I
ll
1' lo
2 lo
3
I
Mas
s (g
)
FIG.
4, N
et c
ost
of t
rans
port
in w
alki
ng l
izar
ds a
s a
func
tion
of b
ody
mas
s. R
edra
wn
from
Gle
eson
(1
979b
).
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
17
1
cons
umpt
ion
whi
le w
alki
ng a
t a g
iven
spe
ed) i
s in
depe
nden
t oft
empe
ratu
re.
In I
guan
a an
d D
ipso
saur
us, t
he c
ost
of t
rans
port
inc
reas
es w
ith i
ncre
asin
g bo
dy t
empe
ratu
re. T
hus,
wal
king
at a
giv
en s
peed
req
uire
s m
ore
ener
gy a
s te
mpe
ratu
re
incr
ease
s.
Cle
arly
, fu
rthe
r in
vest
igat
ion
of
the
ther
mal
de
pend
ence
of l
ocom
otor
y co
sts
of r
epti
les
is r
equi
red.
Th
e re
sult
s of
thes
e st
udie
s m
ay b
e an
tici
pate
d to
hav
e im
port
ant
ener
geti
c an
d ec
olog
ical
im
plic
atio
ns.
Bod
y te
mpe
ratu
re h
as b
een
show
n in
the
pre
viou
s se
ctio
n (S
ectio
n 11
-B)
to in
flue
nce
max
imal
oxy
gen
cons
umpt
ion
of r
epti
les.
Low
bod
y te
mpe
ra-
ture
s in
hibi
t max
imal
rat
es o
f oxy
gen
util
izat
ion.
It m
ay b
e an
tici
pate
d th
en
that
cap
acit
ies
for s
usta
inab
le lo
com
otio
n m
ight
like
wis
e be
inhi
bite
d by
low
bo
dy te
mpe
ratu
res.
A r
epti
le a
t low
tem
pera
ture
s m
ight
att
ain
the
limits
of
its
aero
bic
scop
e an
d it
s m
axim
al a
erob
ic s
peed
at l
ower
lev
els
of e
xert
ion.
T
he
basi
s fo
r th
is p
redi
ctio
n is
sho
wn
in F
ig.
5. I
n t
his
figu
re,
oxyg
en
cons
umpt
ion
is g
iven
as
a fu
ncti
on o
f sp
eed
for
liza
rds
of l
o-,
loo-
, an
d 10
00-g
bod
y m
ass.
Loc
omot
ory
cost
s w
ere
esti
mat
ed b
y ca
lcul
atin
g th
e Y
-int
erce
pts
as 1
.7 x
rest
ing
oxyg
en c
onsu
mpt
ion
at 3
0°C
(T
able
I)
and
addi
ng th
e ne
t cos
t of t
rans
port
(pr
evio
us e
quat
ion,
Gle
eson
, 19
79b)
. The
se
Wal
kin
g
spee
d (k
rn/h
)
FIG
. 5. O
xyge
n co
nsum
ptio
n as
a fu
nctio
n of
wal
king
spc
cd in
liza
rds o
f dir
crcn
t bod
y m
ass.
hla
xim
al
oxyg
cn c
onsu
mpt
ion
as a
fun
ctio
n of
bod
y tc
mpc
ratu
rc i
s al
so i
ndic
atcd
. Sc
c rc
xt f
or m
crho
d of
ca
lcul
atio
n.
172
AL
BE
RT
F.
BE
NN
ET
T
valu
es a
re o
nly
gene
raliz
ed e
stim
ates
and
will
act
uall
y va
ry s
omew
hat
with
bo
dy t
empe
ratu
re.
Ove
rlai
d on
the
se d
ata
are
inde
pend
ent
calc
ulat
ions
of
max
imal
oxy
gen
cons
umpt
ion
(Tab
le 1
11).
Th
e in
ters
ecti
ons
of th
e tw
o se
ts
of li
nes
indi
cate
the
pred
icte
d m
axim
al a
erob
ic s
peed
s, i.
e. th
e gr
eate
st s
peed
w
hich
co
uld
be
sust
aine
d at
tha
t te
mpe
ratu
re.
Bod
y te
mpe
ratu
re i
s pr
edic
ted
to h
ave
a pr
onou
nced
inf
luen
ce o
n su
stai
nabl
e ac
tivity
cap
acity
. M
axim
al a
erob
ic sp
eed
is p
redi
cted
at o
nly
0.1
km/h
at 2
0°C
for l
izar
ds o
ver
this
ent
ire
size
ran
ge.
It in
crea
ses
to 0
.4 k
m/h
at
30°C
and
0.6
5 km
/h a
t 35
°C. T
he
pred
icte
d Ql
o va
lues
ove
r th
is r
ange
are
3.7
-4.4
at
20-3
0°C
an
d 2.
8-3.
0 at
30-
3S°C
, in
dica
ting
a v
ery
grea
t te
mpe
ratu
re d
epen
denc
e. T
he
size
dep
ende
nce
of m
axim
al o
xyge
n co
nsum
ptio
n at
40°
C (
Sect
ion
11-B
) m
akes
th
e pr
edic
ted
max
imal
ae
robi
c sp
eed
high
ly
size
de
pend
ent,
de
crea
sing
fro
m 1
.1 k
m/h
for
a 1
0-g
lizar
d to
0.5
5 km
/h fo
r a 1
000-
g an
imal
. In
th
e la
tter
si
ze c
lass
, th
e pr
edic
ted
perf
orm
ance
ac
tual
ly
decr
ease
s be
twee
n 35
and
40°
C.
Th
e pr
edic
tion
s of
thi
s m
odel
ac
cord
fa
irly
wel
l w
ith
the
ther
mal
de
pend
ence
of
su
stai
nabl
e lo
com
otor
y ca
paci
ty
obse
rved
in
Ig
uana
(M
ober
ly,
1968
b) a
nd D
ipso
saur
us (
John
-Ald
er
and
Ben
nett
, 19
81).
In
Igua
na,
max
imal
sus
tain
ed w
alki
ng s
peed
s (>
10
min
) ar
e 0.
17,
0.45
, 0.
52,
and
0.45
km
/h a
t 20
, 30
, 35
, an
d 40
°C r
espe
ctiv
ely.
Bot
h th
e qu
anti
tati
ve
leve
ls o
f m
axim
al a
erob
ic s
peed
and
the
pat
tern
of
ther
mal
dep
ende
nce
(Qlo
=2.
7 at
20-
30°C
, 1.
3 at
30-
3S°C
, an
d 0.
7 at
35
40
°C)
are
sim
ilar
to
pred
icte
d va
lues
of
1-kg
liz
ards
. S
usta
inab
le s
peed
(>
15 m
in)
incr
ease
s fr
om 0
.3 k
m/h
at
25°C
to 0
.8 k
m/h
at 4
0°C
in 5
0-g
Dip
sosa
urus
(Ql0
= 1
.9).
The
se v
alue
s ar
e al
so v
ery
clos
e to
pre
dict
ed p
erfo
rman
ce l
evel
s. I
t sh
ould
be
em
phas
ized
tha
t th
is r
egre
ssio
n m
odel
obs
cure
s re
al v
aria
bilit
y in
the
ac
tivi
ty c
apac
itie
s am
ong
diff
eren
t sp
ecie
s an
d sh
ould
be
used
onl
y to
ex
amin
e ge
nera
l tre
nds.
For
inst
ance
, the
loco
mot
ory
capa
citie
s of
the
lizar
d C
nem
zdop
horu
s m
urin
us f
all c
onsi
dera
bly
shor
t of
tho
se p
redi
cted
(B
enne
tt
and
Gle
eson
, 19
79).
V
aran
us
exan
them
atic
us h
as
subs
tant
iall
y gr
eate
r ae
robi
c sc
ope
and
cons
eque
ntly
twic
e th
e m
axim
al a
erob
ic sp
eed
of s
imila
rly
size
d Ig
uana
igu
ana
(Woo
d et
a!.,
1978
; Gle
eson
et a
!., 19
80).
How
ever
, the
pr
edic
ted
effe
ct o
f bo
dy t
empe
ratu
re o
n lo
com
otor
y st
amin
a is
gen
eral
ly
supp
orte
d by
the
ava
ilabl
e da
ta a
nd m
erit
s ad
diti
onal
inve
stig
atio
n.
Th
e m
axim
al
aero
bic
spee
ds c
alcu
late
d an
d ob
serv
ed
for
terr
estr
ial
rept
iles
are
ver
y sl
ow a
nd t
he r
ange
of
sust
aina
ble
rate
s of
loc
omot
ion
is
quit
e na
rrow
, pa
rtic
ular
ly
so
at
low
bo
dy
tem
pera
ture
s.
Ter
rest
rial
m
amm
als,
with
the
ir s
ubst
anti
ally
gre
ater
aer
obic
sco
pes
and
max
imal
rat
es
of o
xyge
n co
nsum
ptio
n, a
re c
apab
le o
f sus
tain
ing
muc
h fa
ster
spe
eds
usin
g ae
robi
c m
etab
olis
m a
lone
. Fig
ure
6 co
mpa
res t
he m
etab
olic
rate
s an
d sp
eeds
of
Igua
na a
nd a
hyp
othe
tica
l mam
mal
of e
qual
siz
e (s
ee B
enne
tt a
nd R
uben
, 19
79, f
or m
etho
d of
cal
cula
tion
of p
redi
cted
mam
mal
ian
aero
bic
fact
ors)
.
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
17
3
Th
e li
zard
rea
ches
max
imal
aer
obic
spe
ed a
t 0.5
km/h
; th
e m
amm
al a
t 4.
1 km
/h.
Th
e g
reat
er a
erob
ic s
cope
per
mit
s a
muc
h br
oade
r ra
nge
of
aero
bica
lly
supp
orte
d ac
tiviti
es i
n th
e m
amm
al.
Ene
rget
ical
ly,
mam
mal
ian
Ioco
mot
ion
per s
e is
qui
te si
mil
ar to
that
of l
izar
ds. T
he
net c
ost o
f tra
nspo
rt
i.e.
the
slop
e of
oxy
gen
cons
umpt
ion
as a
fun
ctio
n of
spe
ed,
in t
he t
wo
grou
ps i
s al
mos
t id
enti
cal
(Bak
ker,
197
2; T
aylo
r, 1
973;
Gle
eson
, 19
79b)
. C
onse
quen
tly,
the
spr
awli
ng-t
ype
gait
of
liza
rds
with
lim
bs fl
exed
at r
ight
an
gles
to
the
body
app
ears
no
mor
e ex
pens
ive
than
the
mor
e er
ect g
ait a
nd
colu
mna
r st
ance
of m
amm
als
(Bak
ker,
197
2; T
aylo
r, 1
973)
. How
ever
, the
se
diff
eren
ces
in l
imb
susp
ensi
ons
are
mor
e ap
pare
nt t
han
real
, si
nce
man
y m
amm
als
have
onl
y pl
anar
rot
atio
n of
the
lim
b an
d m
aint
ain
the
flex
ion
abou
t th
e jo
ints
(B
enne
tt a
nd
Dal
zell
, 19
73).
In t
otal
met
abol
ic c
ost,
how
ever
, lo
com
otio
n is
con
side
rabl
y le
ss e
xpen
sive
for
the
liz
ards
, as
is
inac
tivi
ty.
Th
e ig
uana
can
w
alk
at i
ts m
axim
al
aero
bic
spee
d w
ith
a m
etab
olic
rat
e eq
uiva
lent
to
that
of
a re
stin
g m
amm
al.
At
any
sust
aina
ble
spee
d, i
t ha
s a
cons
ider
ably
low
er o
xyge
n co
nsum
ptio
n th
an a
mam
mal
tr
avel
ing
at t
he s
ame
spee
d.
We
may
exa
min
e ho
w d
iffe
rent
fac
tors
aff
ect
loco
mot
ory
ener
getic
s by
ca
lcul
atin
g ho
w m
uch
ener
gy i
s re
quir
ed
for
a re
ptil
e to
mov
e a
give
n di
stan
ce.
In th
is c
ase,
we
can
calc
ulat
e th
e en
ergy
req
uire
d fo
r a
lizar
d to
w
alk
1 km
. Tot
al p
ower
inp
uts a
re c
alcu
late
d in
Tab
le V
I. T
he
cost
dep
ends
on
spe
ed a
nd o
n bo
dy s
ize,
and
on
body
tem
pera
ture
(in
two
of th
ree
spec
ies
exam
ined
).
Th
e t
otal
w
ork
requ
ired
de
crea
ses
as s
peed
in
crea
ses,
as
FIG
. 6. O
xyge
n co
nsum
ptio
n as
a fu
ncti
on o
f spe
ed in
a I-kg
lizar
d (I
guan
a) an
d a
hypo
thet
ical
mam
mal
of
equ
al s
i7x.
Red
raw
n fr
om B
enne
tt a
nd R
uben
, (19
79);
see
rcf
crcn
cc f
or m
etho
d of
cal
cula
tion
.
AL
BE
RT
F.
BE
NN
ET
T
TA
BL
E
VI
Cos
t of
wal
king
I k
m
Spee
d K
ilojo
ules
km/h
10
g
100
g 10
00 g
Lizu
rds
0.1
0.98
6.
14
38.8
2 0.
5 0.
54
3.15
18
.54
1 .O
0.48
2.
77
16.0
1 M
amm
als
0.1
7.46
40
.82
225.
18
0.5
2.03
10
.33
53.6
3 1.
0 1.
35
6.5 1
32
.18
Wor
k in
put
calc
ulat
ed a
t 1.
0 m
l O
z=20
.1
J (R
Q=0
.8).
Liz
ard
data
from
Tab
le I
and
Gle
eson
, 19
79b;
mam
mal
ian
data
fro
m T
aylo
r, 1
973.
Mob
erly
(19
68b)
poi
nted
out
, be
caus
e of
the
lon
ger
dura
tion
of
"mai
n-
tena
nce
cost
s"
at s
low
spe
eds.
Thu
s, o
nly
abou
t ha
lf a
s m
uch
ener
gy i
s re
quir
ed t
o w
alk
the
dist
ance
at
1.0
km/h
as
at 0
.1 k
m/h
. Thu
s, if
trav
ersi
ng
a gi
ven
dist
ance
wer
e th
e on
ly f
acto
r of
impo
rtan
ce, e
nerg
y w
ould
be
mos
t co
nser
ved
by
wal
king
at
the
grea
test
pos
sibl
e sp
eed
with
in
aero
bica
lly
supp
orta
ble
lim
its.
Th
e ae
robi
c sc
ope
and
max
imal
sus
tain
able
spe
ed s
et a
n up
per
lim
it o
n th
ese
rate
s, a
nd b
oth
body
tem
pera
ture
(Fig
. 5)
and
aer
obic
ph
ysio
logy
may
pre
vent
the
mai
nten
ance
of
even
mod
erat
e sp
eeds
. F
or
inst
ance
, at
20°C, o
nly
0.1
km/h
is
an a
cces
sibl
e sp
eed;
any
thin
g gr
eate
r re
quir
es s
uppl
emen
tal
anae
robi
c m
etab
olis
m a
nd e
ntai
ls e
xhau
stio
n. T
he
tota
l cos
t of t
rans
port
incr
ease
s w
ith b
ody
size
, as
the
mas
s to
be
tran
spor
ted
thro
ugh
the
dist
ance
is
grea
ter.
A t
enfo
ld i
ncre
men
t in
mas
s re
quir
es a
si
xfol
d in
crem
ent
in w
ork
inpu
t to
mov
e it
. T
he
mas
s-sp
ecif
ic c
osts
are
lo
wer
for
lar
ger
anim
als,
but
thi
s is
sca
nt c
omfo
rt a
s th
ey m
ust m
ove
thei
r en
tire
bod
ies
whe
n th
ey w
alk.
Th
e en
erge
tic
econ
omy
asso
ciat
ed w
ith
ecto
ther
mic
met
abol
ism
is
unde
rsco
red
by c
ompa
riso
n of
the
se d
ata
with
th
ose
for
mam
mal
s. P
arti
cula
rly
at s
low
spe
eds,
the
cos
t of
mov
ing
a gi
ven
dist
ance
for
a re
ptil
e is
onl
y a
frac
tion
of t
hat f
or a
mam
mal
of t
he s
ame
size
at
the
sam
e sp
eed.
In
sum
mar
y, t
he c
osts
of
terr
estr
ial
loco
mot
ion
are
very
hig
h fo
r rep
tile
s in
com
pari
son
with
the
ir l
imit
ed a
erob
ic s
cope
s. T
hey
reac
h th
eir
aero
bic
lim
its
at v
ery
low
spe
eds
and
mus
t su
pple
men
t ae
robi
osis
w
ith
othe
r m
etab
olic
pa
thw
ays.
T
he
stro
ng t
herm
al
depe
nden
ce o
f th
eir
oxyg
en
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
17
5
cons
umpt
ion,
alt
houg
h re
duci
ng e
nerg
y ex
pend
itur
e at
low
tem
pera
ture
s,
crea
tes
addi
tion
al b
ehav
iora
l di
ffic
ultie
s, v
ery
grea
tly
redu
cing
abi
lity
to
supp
ort a
nd s
usta
in a
ctiv
ity
at th
ese
low
tem
pera
ture
s. T
hese
rela
tions
hips
pl
ace
seve
re li
mit
atio
ns o
n th
e be
havi
oral
pot
enti
al o
f re
ptile
s.
3. C
ost
of Sw
imm
ing
Sw
imm
ing,
by
or
gani
sms
adap
ted
to i
t as
the
ir p
rim
ary
mea
ns o
f lo
com
otio
n,
is t
he m
ost
econ
omic
al
form
of
tran
spor
t (T
ucke
r,
1970
; Sc
hmid
t-N
iels
en,
1972
). L
ocom
otor
y co
sts
of a
1-k
g fi
sh,
for
inst
ance
, are
on
ly o
ne-e
ight
h th
ose
of a
n eq
ual-
size
d te
rres
tria
l w
alke
r (Sc
hmid
t-N
iels
en,
1972
). T
he
cost
of s
wim
min
g ha
s be
en e
valu
ated
for
onl
y tw
o re
ptile
s: g
reen
tu
rtle
s (C
helo
nia
myd
as) (
Pran
ge,
1976
) and
mar
ine
igua
nas
(Am
blJl
rh~t
nchu
s cr
istn
tus;
Gle
eson
, 197
9b; V
leck
et a
l., 1
981)
. The
se a
nim
als
diff
er fr
om f
ish,
as
the
ir o
xyge
n co
nsum
ptio
n in
crea
ses
linea
rly
with
inc
reas
ing
spee
d. B
oth
rept
iles
w
hile
sw
imm
ing
achi
eve
sign
ific
ant
econ
omy
over
te
rres
tria
l lo
com
otio
n, b
ut n
eith
er a
ttai
ns t
he lo
w e
nerg
y co
sts
of s
wim
min
g fi
sh. T
he
net
cost
of
tran
spor
t of
gre
en t
urtl
es is
app
roxi
mat
ely
twic
e th
at o
f m
arin
e ig
uana
s an
d is
abo
ut
five
tim
es t
hat
of
salm
onid
fi
shes
(B
rett
, 19
64;
Sch
mid
t-N
iels
en,
1972
). T
hese
add
itio
nal
cost
s m
ay b
e du
e to
sur
face
sw
imm
ing
activ
ity;
the
turt
le s
urfa
ces
for
air
and
the
igua
na r
emai
ns
buoy
antl
y sw
imm
ing
at
the
surf
ace,
bo
th
crea
ting
co
nsid
erab
le w
ake
form
atio
n an
d th
us i
ncre
asin
g to
tal
ener
gy e
xpen
ditu
re (
Pran
ge,
1976
; V
leck
et
al.,
1980
). T
he
cost
s of
sw
imm
ing
and
wal
king
in
mar
ine
igua
nas
are
com
pare
d in
Fig
. 7. T
he
(tot
al) c
ost o
f lo
com
otio
n of
an
igua
na w
alki
ng
at 1
.0 k
m/h
, its
max
imal
aer
obic
spe
ed, i
s fo
ur ti
mes
that
whe
n sw
imm
ing
at
Wal
king
I
0.
t
%xO-
-0
4 O
-0-0-2 O;
Sw
imm
ing
O R
012
I I
I I
I I
I I
0.6
1.0
1.4
1.8
km
/h
FIG
. 7.
Am
b!yr
hync
hus
cris
tatu
s.
Oxy
gen
cons
umpt
ion
of a
dult
mar
ine
igua
nas
wal
king
on
a
nlot
or-d
rive
n tr
eadm
ill a
t 35
°C a
nd s
wim
min
g at
25'
C.
Red
raw
n fr
om G
lccs
on (
1979
h).
3. T
HE
EN
ER
GE
T~
CS
OF
RE
PT
IL~
IAN
AC
T~
V~
TY
17
7
and
oxyg
en c
onsu
mpt
ion
duri
ng a
ctiv
ity.
Alt
houg
h th
ese
mea
sure
men
ts a
re
feas
ible
, th
ey h
ave
not
yet
been
und
erta
ken
for
rept
iles
. V
ery
shor
t-te
rm a
ctiv
ity
(i.e
. a
few
sec
onds
) m
ay b
e su
ppor
ted
by t
he
cata
boli
sm o
f en
doge
nous
sto
res
of A
TP
and
/or
crea
tine
pho
spha
te w
ithin
th
e sk
elet
al m
uscl
e. L
evel
s of
bot
h th
ese
com
poun
ds d
ecre
ase
duri
ng b
urst
be
havi
or i
n th
e liz
ard
Scel
opor
us o
ccid
enta
lis (
A.
F.
Ben
nett
and
T.
T.
Gle
eson
, un
publ
ishe
d).
Due
to
met
hodo
logi
cal
diff
icul
ties,
no
exte
nsiv
e m
easu
rem
ents
of
the
util
izat
ion
of t
hese
com
poun
ds h
ave
been
mad
e fo
r ac
tive
rep
tile
s. I
t is
pro
babl
e th
at t
heir
cat
abol
ism
is
very
sig
nifi
cant
in
fuel
ing
shor
t, in
tens
e bu
rsts
tha
t ch
arac
teri
ze m
uch
avoi
danc
e be
havi
or o
f re
ptil
es.
The
ir s
igni
fica
nce
mer
its
muc
h fu
rthe
r ex
amin
atio
n.
In a
llig
ator
s, t
urtl
es,
lizar
ds,
and
snak
es,
inte
nse
beha
vior
of
long
er
dura
tion
(i.e
. 5
s to
5 m
in)
invo
lves
the
pro
duct
ion
and
accu
mul
atio
n of
la
rge
amou
nts
of l
acti
c ac
id (
Cou
lson
and
Her
nand
ez,
1964
; M
ober
ly,
1968
a,b;
Ben
nett
and
Lic
ht,
1972
; B
enne
tt a
nd D
awso
n, 1
972;
Ben
nett
, 19
73; G
atte
n, 1
974,
197
5; B
enne
tt a
nd R
uben
, 19
75; B
enne
tt e
t al.,
197
5;
Bar
thol
omew
et a
l.,
1976
; Rub
en,
1976
; Ben
nett
and
Gle
eson
, 19
76; G
ratz
an
d H
utch
ison
, 19
77; P
ough
, 19
77, 1
978;
Gle
eson
, 19
80ab
; Mitc
hell
et a
l.,
1981
). T
he
exte
nt
and
sign
ific
ance
of
re
ptil
ian
anae
robi
c m
etab
olis
m
invo
lvin
g la
ctic
aci
d fo
rmat
ion
has
rece
ived
con
side
rabl
e at
tent
ion;
the
se
find
ings
are
dis
cuss
ed
here
. T
he
accu
mul
atio
n of
oth
er a
naer
obic
end
- pr
oduc
ts h
as n
ot b
een
wid
ely
stud
ied;
how
ever
, pr
elim
inar
y ev
iden
ce
sugg
ests
the
se p
rodu
cts
have
lit
tle
ener
geti
c si
gnif
ican
ce.
In t
he l
izar
ds
Scel
opor
us o
ccid
enta
lis a
nd X
antu
sia
vigi
lis, t
he t
otal
for
mat
ion
of p
yruv
ic
acid
, suc
cina
te, a
nd a
lani
ne a
ccou
nt f
or le
ss th
an 4
% o
f th
e A
TP
form
atio
n as
soci
ated
with
lac
tic
acid
pro
duct
ion
(A.
F.
Ben
nett
and
T. T
. Gle
eson
, un
publ
ishe
d).
2. A
dvan
tage
s an
d D
isad
vant
ages
of A
naer
obic
Met
abol
ism
In
com
pari
son
to a
erob
ic e
nerg
y ut
iliz
atio
n, a
naer
obic
met
abol
ism
as
a m
eans
of
supp
orti
ng m
uscu
lar
acti
vity
has
con
spic
uous
adv
anta
ges
and
disa
dvan
tage
s (B
enne
tt a
nd R
uben
, 19
79; C
ouls
on,
1979
; Ben
nett
, 19
80a)
. O
xyge
n m
ust
be t
rans
port
ed
for
a co
nsid
erab
le d
ista
nce
to i
ts s
ite
of
util
izat
ion;
how
ever
, th
e re
acta
nts
for
anae
robi
c m
etab
olis
m a
re e
nclo
sed
wit
hin
the
mus
cle
cells
. Enz
ymes
, fue
l (m
uscl
e gl
ycog
en),
and
sto
rage
form
s of
hi
gh
ener
gy
phos
phat
e co
mpo
unds
(A
TP
, cr
eati
ne
phos
phat
e)
are
avai
labl
e fo
r im
med
iate
act
ivat
ion
and
utili
zatio
n w
itho
ut a
sig
nifi
cant
tim
e la
g. I
n ad
diti
on, t
he p
oten
tial
rat
e of
AT
P g
ener
atio
n by
ana
erob
ic s
yste
ms
is m
uch
larg
er th
an t
hat f
or r
epti
lian
aer
obic
met
abol
ism
(se
e be
low
). T
hus,
an
aero
bic
met
abol
ism
lac
ks t
he t
empo
ral
and
quan
tita
tive
lim
itatio
ns o
f ae
robi
osis
. H
owev
er,
anae
robi
osis
cre
ates
pr
onou
nced
ph
ysio
logi
cal
diff
icul
ties.
176
AL
BE
RT
F.
BE
NN
ET
T
the
sam
e sp
eed.
Sw
imm
ing
anim
als
are
capa
ble
of s
usta
inin
g sp
eeds
nea
rly
twic
e th
is g
reat
. How
ever
, max
imal
bur
st s
peed
s w
hile
run
ning
on
land
are
m
uch
grea
ter t
han
burs
t sw
imm
ing
spee
d in
the
wat
er (9
.0 v
ersu
s 2.
7 km
/h;
Bar
thol
omew
et
a/.
, 19
76; G
lees
on,
1979
b). T
he
econ
omy
asso
ciat
ed w
ith
sust
aine
d sw
imm
ing
may
be
part
ly d
ue t
o de
crea
sed
body
tem
pera
ture
in
the
wat
er a
nd/o
r th
e bu
oyan
t su
ppor
t of
the
wat
er.
Sw
imm
ing
tran
spor
t,
then
, is
mor
e en
erge
tical
ly c
onse
rvat
ive
and
shou
ld b
e fa
vore
d on
str
ictl
y en
erge
tic
grou
nds
by a
n or
gani
sm w
hich
may
cho
ose
eith
er.
The
re a
re,
how
ever
, co
mpe
nsat
ory
disa
dvan
tage
s, s
uch
as e
xpos
ure
to a
new
set
of
pred
ator
s, r
educ
ed m
axim
al s
peed
, an
d ge
nera
lly r
educ
ed b
ody
tem
pera
- tu
re,
affe
ctin
g m
any
othe
r ph
ysio
logi
cal
syst
ems.
111.
No
n-s
ust
ain
able
Act
ivit
y a
nd
An
aero
bic
Met
abo
lism
Th
e le
vel
of e
xert
ion
that
mos
t li
zard
s ca
n su
ppor
t ae
robi
cally
is
very
li
mit
ed,
as s
een
in t
he p
revi
ous
sect
ion.
Any
act
ivity
gre
ater
tha
n th
ese
mod
est
leve
ls m
ust
be f
uele
d w
ith s
uppl
emen
tal
anae
robi
c m
etab
olis
m.
In
addi
tion
, ev
en m
oder
ate
leve
ls o
f ac
tivi
ty o
ften
hav
e an
ini
tial
anae
robi
c co
mpo
nent
as
oxyg
en c
onsu
mpt
ion
cann
ot b
e ra
ised
ins
tant
ly t
o it
s fi
nal
max
imum
val
ue.
Th
e la
g in
its
dev
elop
men
t m
ust
also
be
supp
lem
ente
d an
aero
bica
lly.
Th
is s
ectio
n w
ill r
evie
w o
ur c
urre
nt k
now
ledg
e co
ncer
ning
th
e ex
tent
and
sig
nifi
canc
e of
ana
erob
iosi
s du
ring
act
ivit
y in
rep
tile
s an
d S
ecti
on I
V w
ill e
xam
ine
the
diff
eren
tial
uti
liza
tion
of a
erob
ic a
nd a
naer
obic
m
etab
olis
m.
1. A
naer
obic
Pat
hway
s in
Rep
tiles
Sin
ce "
anae
robi
c m
etab
olis
m"
refe
rs to
any
met
abol
ic p
athw
ay th
at d
oes
not i
nvol
ve th
e ut
iliz
atio
n of
mol
ecul
ar o
xyge
n, n
umer
ous
pote
ntia
l rea
ctio
n se
ries
cou
ld y
ield
a n
et a
mou
nt o
f A
TP
in
supp
ort
of m
uscu
lar
acti
vity
. T
hese
ser
ies
have
not
bee
n ch
arac
teri
zed
for
any
anim
al.
Acc
umul
atio
n of
so
me
likel
y an
aero
bica
lly f
orm
ed e
nd-p
rodu
cts
and
depl
etio
n of
pot
enti
al
ener
gy s
tore
d ha
s be
en m
easu
red
for
som
e re
ptil
es.
How
ever
, th
is e
clet
ic
appr
oach
may
mis
s im
port
ant r
eact
ions
and
may
lead
to a
n un
dere
stim
atio
n of
the
exte
nt o
f ana
erob
ic m
etab
olis
m i
f sig
nifi
cant
and
unk
now
n pa
thw
ays
are
not
assa
yed.
D
eter
min
atio
n of
the
ext
ent
of a
naer
obio
sis
requ
ires
si
mul
tane
ous
mea
sure
men
ts o
f to
tal
heat
pro
duct
ion
by d
irec
t cal
orim
etry
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
.IA
N
AC
TIV
ITY
17
7
and
oxyg
en c
onsu
mpt
ion
duri
ng a
ctiv
ity. A
ltho
ugh
thes
e m
easu
rem
ents
are
fe
asib
le,
they
hav
e no
t ye
t be
en u
nder
take
n fo
r re
ptile
s.
Ver
y sh
ort-
term
act
ivit
y (i
.e.
a fe
w s
econ
ds)
may
be
supp
orte
d by
the
ca
tabo
lism
of
endo
geno
us s
tore
s of
AT
P a
nd/o
r cr
eati
ne p
hosp
hate
with
in
the
skel
etal
mus
cle.
Lev
els
of b
oth
thes
e co
mpo
unds
dec
reas
e du
ring
bur
st
beha
vior
in
the
liza
rd S
celo
poru
s oc
cide
ntal
is (
A.
F.
Ben
nett
and
T.
T.
Gle
eson
, un
publ
ishe
d).
Du
e to
met
hodo
logi
cal
diff
icul
ties,
no
exte
nsiv
e m
easu
rem
ents
of
the
util
izat
ion
of t
hese
com
poun
ds h
ave
been
mad
e fo
r ac
tive
rept
iles
. It
is
prob
able
tha
t th
eir
cata
boli
sm i
s ve
ry s
igni
fica
nt i
n fu
elin
g sh
ort,
int
ense
bur
sts
that
cha
ract
eriz
e m
uch
avoi
danc
e be
havi
or o
f re
ptil
es.
The
ir s
igni
fica
nce
mer
its
muc
h fu
rthe
r ex
amin
atio
n.
In a
lliga
tors
, tu
rtle
s,
lizar
ds,
and
snak
es,
inte
nse
beha
vior
of
long
er
dura
tion
(i.e
. 5
s to
5 m
in)
invo
lves
the
pro
duct
ion
and
accu
mul
atio
n of
la
rge
amou
nts
of l
actic
aci
d (C
ouls
on a
nd H
erna
ndez
, 19
64;
Mob
erly
, 19
68a,
b; B
enne
tt a
nd L
icht
, 19
72; B
enne
tt a
nd D
awso
n, 1
972;
Ben
nett,
19
73; G
atte
n, 1
974,
197
5; B
enne
tt a
nd R
uben
, 19
75; B
enne
tt e
t al
., 19
75;
Bar
thol
omew
et
al.,
1976
; Rub
en,
1976
; Ben
nett
and
Gle
eson
, 19
76; G
ratz
an
d H
utch
ison
, 19
77; P
ough
, 19
77, 1
978;
Gle
eson
, 19
80ab
; Mitc
hell
et a
l.,
1981
). T
he
exte
nt
and
sign
ific
ance
of
rept
ilia
n an
aero
bic
met
abol
ism
in
volv
ing
lact
ic a
cid
form
atio
n ha
s re
ceiv
ed c
onsi
dera
ble
atte
ntio
n; t
hese
fi
ndin
gs a
re d
iscu
ssed
he
re.
Th
e ac
cum
ulat
ion
of o
ther
ana
erob
ic e
nd-
prod
ucts
ha
s no
t be
en
wid
ely
stud
ied;
how
ever
, pr
elim
inar
y ev
iden
ce
sugg
ests
the
se p
rodu
cts
have
lit
tle
ener
geti
c si
gnif
ican
ce.
In t
he l
izar
ds
Scel
opor
us o
ccid
enta
lis a
nd X
antu
sia
vigi
lis,
the
tota
l fo
rmat
ion
of p
yruv
ic
acid
, suc
cina
te, a
nd a
lani
ne a
ccou
nt f
or le
ss th
an 4
% o
f th
e A
TP
form
atio
n as
soci
ated
with
lac
tic
acid
pro
duct
ion
(A. F
. Ben
nett
and
T. T
. G
lees
on,
unpu
blis
hed)
.
2. A
dvan
tage
s an
d D
isad
vant
ages
of A
naer
obic
Met
abol
ism
In
com
pari
son
to a
erob
ic e
nerg
y ut
iliz
atio
n, a
naer
obic
met
abol
ism
as
a m
eans
of
supp
orti
ng m
uscu
lar
acti
vity
has
con
spic
uous
adv
anta
ges
and
disa
dvan
tage
s (B
enne
tt a
nd R
uben
, 19
79; C
ouls
on,
1979
; Ben
nett
, 19
80a)
. O
xyge
n m
ust
be t
rans
port
ed
for
a co
nsid
erab
le d
ista
nce
to i
ts s
ite
of
utili
zatio
n; h
owev
er,
the
reac
tant
s fo
r an
aero
bic
met
abol
ism
are
enc
lose
d w
ithi
n th
e m
uscl
e ce
lls. E
nzym
es, f
uel (
mus
cle
glyc
ogen
), a
nd s
tora
ge fo
rms
of
high
en
ergy
pho
spha
te
com
poun
ds (
AT
P,
crea
tine
ph
osph
ate)
are
av
aila
ble
for
imm
edia
te a
ctiv
atio
n an
d ut
iliz
atio
n w
itho
ut a
sig
nifi
cant
tim
e la
g. I
n ad
diti
on, t
he p
oten
tial
rat
e of
AT
P g
ener
atio
n by
ana
erob
ic s
yste
ms
is m
uch
larg
er th
an t
hat f
or re
ptil
ian
aero
bic
met
abol
ism
(se
e be
low
). T
hus,
an
aero
bic
met
abol
ism
lac
ks t
he t
empo
ral
and
quan
tita
tive
lim
itatio
ns o
f ae
robi
osis
. H
owev
er,
anae
robi
osis
cre
ates
pro
noun
ced
phys
iolo
gica
l di
ffic
ultie
s.
178
AL
BE
RT
F.
BE
NN
ET
T
Act
ivat
ion
of c
onsi
dera
ble
anae
robi
c m
etab
olis
m i
s st
rong
ly a
ssoc
iate
d w
ith
exha
usti
on.
Rep
tile
s w
ith l
arge
acc
umul
atio
ns o
f la
ctic
aci
d ha
ve g
reat
ly
dim
inis
hed
beha
vior
al c
apac
itie
s and
will
not
resp
ond
to fu
rthe
r sti
mul
atio
n (M
ober
ly,
1968
b; B
enne
tt a
nd L
icht
, 19
72;
Ben
nett
et
al.,
1975
; B
ar-
thol
omew
et
al.,
1976
; R
uben
, 19
76;
Ben
nett
and
Gle
eson
, 19
76;
Gra
tz
and
Hut
chis
on,
1977
; Pou
gh,
1977
, 19
78; G
lees
on,
1980
a, b
). T
he
casu
al
rela
tion
ship
s as
soci
ated
with
thi
s ex
haus
tion
are
not
kno
wn
and
wou
ld
cons
titu
te a
n in
tere
stin
g ar
ea o
f st
udy.
Lac
tic
acid
is
a m
oder
atel
y st
rong
ac
id (
pK=
3.9)
. It
s pr
oduc
tion
dur
ing
rept
ilia
n ac
tivity
gre
atly
ele
vate
s th
e co
ncen
trat
ion
of h
ydro
gen
ions
in b
oth
bloo
d an
d m
uscl
e (B
enne
tt,
1973
; G
atte
n,
1975
; R
uben
, 19
79;
Mit
chel
l et
al.,
19
81).
For
ins
tanc
e, i
n th
e ra
ttle
snak
e, C
rota
lus
uiri
dis,
blo
od p
H d
ecre
ases
fro
m 7
.38
to 6
.79
afte
r 5
min
of i
nten
se a
ctiv
ity
at 3
S°C
. Th
is c
hang
e in
aci
d-ba
se b
alan
ce o
f bo
dy
flui
ds
indu
ces
cons
ider
able
di
ffic
ultie
s fo
r he
mog
lobi
n an
d en
zym
atic
fu
ncti
on.
Th
e ac
idos
is i
s al
so a
ssoc
iate
d w
ith m
ajor
dis
rupt
ions
in
bloo
d ca
lciu
m l
evel
s (R
uben
and
Ben
nett
, 19
81; R
uben
, 19
83).
Ano
ther
dis
adva
ntag
e of
ana
erob
ic m
etab
olis
m is
its
low
yie
ld o
f AT
P to
su
bstr
ate
cata
boli
zed.
A n
et y
ield
of
only
thr
ee A
TP
mol
ecul
es i
s pr
oduc
ed
duri
ng t
he a
naer
obic
bre
akdo
wn
of a
gly
coge
n un
it t
o la
ctic
aci
d, w
here
as
37-3
9 A
TP
mol
ecul
es w
ould
be
prod
uced
by
aero
bic
met
abol
ism
. H
ence
, an
aero
bios
is is
onl
y 8-
10%
as
eff
icie
nt a
s ae
robi
osis
on
the
basi
s of
ene
rgy
prod
ucti
on p
er u
nit
of f
uel
subs
trat
e. C
onse
quen
tly,
the
rat
e of
sub
stra
te
depl
etio
n m
ust b
e 10
-12
tim
es a
s gr
eat t
o su
stai
n an
equ
ival
ent r
ate
of A
TP
pr
oduc
tion
. If
sub
stra
te i
s li
mit
ing,
thi
s in
effi
cien
cy m
ay c
onst
itut
e an
im
port
ant f
acto
r cur
tail
ing
acti
vity
. How
ever
, th
is a
naer
obic
pat
hway
is n
ot
inhe
rent
ly
inef
fici
ent
on
a th
erm
odyn
amic
ba
sis;
bo
th
path
way
s tr
ap
appr
oxim
atel
y 40
% o
f the
pot
enti
al e
nerg
y re
leas
ed (
Leh
ning
er,
1975
). T
he
lact
ic a
cid
prod
uced
may
be
reco
nver
ted
to g
lyco
gen
and
reus
ed s
ubse
- qu
entl
y, b
ut s
uch
gluc
oneo
geni
c re
synt
hesi
s re
quir
es s
even
hig
h en
ergy
ph
osph
ate
mol
ecul
es p
er g
lyco
gen
unit
, a
net
loss
of
four
AT
P e
quiv
alen
ts
for
one
cycl
e. T
his
syn
thet
ic c
ost
wou
ld
be a
n ad
diti
onal
lon
ger-
term
ex
pens
e as
soci
ated
with
rec
over
y fr
om a
naer
obic
ally
sup
port
ed a
ctiv
ity.
H
owev
er,
the
fate
of
lact
ic a
cid
duri
ng r
ecov
ery
from
act
ivit
y in
rep
tile
s is
un
know
n. S
ever
al s
tudi
es h
ave
atte
mpt
ed c
ompa
rtm
enta
l ana
lyse
s of
lact
ate
rem
oval
and
/or
carb
ohyd
rate
resy
nthe
sis
duri
ng re
cove
ry (
Mob
erly
, 19
68a;
B
enne
tt a
nd L
icht
, 19
72;
Gra
tz a
nd H
utch
ison
, 19
77;
Cou
lson
, 19
80;
Gle
eson
, 19
80b)
, but
the
cru
cial
stu
dies
exa
min
ing
the
quan
tita
tive
fat
e of
ex
ogen
eous
ly a
dmin
iste
red
labe
led
lact
ate
have
not
bee
n un
dert
aken
. T
his
is
ano
ther
are
a in
whi
ch f
urth
er r
esea
rch
may
be
expe
cted
to
incr
ease
our
un
ders
tand
ing
of t
he e
nerg
etic
bas
is o
f re
ptil
ian
activ
ity.
In c
ontr
ast
to t
he i
neff
icie
ncie
s of
AT
P g
ener
atio
n an
d re
synt
hesi
s,
anae
robi
c m
etab
olis
m i
s m
uch
mor
e ef
fici
ent
at g
ener
atin
g A
TP
per
uni
t
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TlL
lAN
AC
TIV
ITY
17
9
tim
e in
rep
tile
s th
an i
s ae
robi
c m
etab
olis
m (
see
bclo
w).
Fro
m a
beh
avio
ral
view
poin
t, an
aero
bios
is i
s th
us m
ore
effi
cien
t th
an a
erob
iosi
s du
ring
ver
y in
tens
e ac
tivity
, su
ch a
s ra
pid
esca
pe o
r pu
rsui
t. M
etab
olic
mod
cs s
houl
d no
t be
cha
ract
eriz
ed a
s "e
ffic
ient
" or
"in
effi
cien
t"
wit
hout
spe
cify
ing
the
crit
eria
con
side
red
for
effi
cien
cy.
1. I
ntro
duct
ory
Ana
erob
ic a
ctiv
ity
ener
geti
cs h
ave
been
ex
amin
ed
for
two
diff
eren
t as
pect
s of
ene
rgy
utili
zatio
n: t
he m
axim
al s
peed
of
ener
gy p
rodu
ctio
n an
d th
e to
tal
cont
ribu
tion
to
a bo
ut o
f ac
tivi
ty (
Ben
nett
and
Lic
ht,
1972
). 'I'h
e fo
rmer
is
mea
sure
d as
the
anae
robi
c sc
ope,
the
rat
e of
lact
ic a
cid
form
atio
n du
ring
the
ini
tial
stag
es o
f vi
goro
us a
ctiv
ity,
usu
ally
dur
ing
thc
firs
t 30
s.
Th
e an
aero
bic
capa
cz/jl
is t
he a
mou
nt o
f la
ctic
aci
d fo
rmed
dur
ing
a lo
ngcr
bo
ut o
f ac
tivity
, us
ually
tha
t pr
eced
ing
exha
usti
on.
Th
e ra
te o
f la
ctic
aci
d fo
rmat
ion
in r
epti
les
is g
reat
ly d
ecre
ased
aft
er th
e fi
rst m
inut
e of
activ
ity a
nd
90%
of
the
even
tual
acc
umul
atio
n ha
s oc
curr
ed a
t 1.
5 m
in (
Ucn
nctt
and
Lic
ht,
1972
; C
ouls
on,
1980
); c
onse
quen
tly,
ana
erob
ic c
apac
ity i
n th
ese
anim
als
may
be
esti
mat
ed o
n th
e ba
sis
of la
ctic
aci
d co
nten
t aft
er 2
+ m
in o
f ac
tivity
. D
eter
min
atio
n of
suc
h va
lues
req
uire
s an
alys
is o
f w
hole
bod
y la
ctat
e co
ncen
trat
ions
in
diff
eren
t gr
oups
of
anim
als
befo
re a
nd a
fter
thc
de
sire
d ac
tivi
ty p
erio
d. B
lood
lac
tate
con
cent
rati
on m
ay in
dica
te th
c ge
ncra
l le
vel
of a
naer
obic
met
abol
ism
, bu
t pr
ovid
es a
n in
adcq
uate
est
imat
c of
an
aero
bic
ener
geti
cs b
ecau
se o
f th
e te
mpo
ral
and
com
part
men
tal
natu
re o
f la
ctat
e di
stri
buti
on (
Ben
nett
and
Lic
ht,
1972
).
2. A
naer
obic
Sco
pe
Tab
le V
II s
how
s th
e m
axim
al r
ates
of
lact
ic a
cid
form
atio
n (a
naer
obic
sc
opes
) of
seve
ral s
mal
l rep
tile
s. E
ach
valu
e is
the
high
est r
epor
ted
over
the
rang
e of
bod
y te
mpe
ratu
res
exam
ined
in
the
stud
y. A
gre
ater
ana
crob
ic
scop
e re
port
ed f
or A
nolis
dur
ing
very
sho
rt-t
erm
act
ivity
(C
ouls
on,
1980
) is
in e
rror
, be
caus
e th
e re
stin
g la
ctat
e co
nten
t w
as n
ot s
ubtr
acte
d pr
ior
to
calc
ulat
ion.
Som
e in
ters
peci
fic
vari
abili
ty i
s ap
pare
nt;
the
fast
cst
rate
is
twic
e th
at o
f th
e sl
owes
t. L
izar
ds t
hat
exhi
bit
mor
e in
tens
c an
d pr
olon
ged
activ
ity
resp
onse
s un
der
expe
rim
enta
l ci
rcum
stan
ces
(e.g
. D
ipso
sarr
rris
, Sc
elop
orus
, U
ta)
have
gre
ater
ana
erob
ic s
cope
s th
an d
o th
ose
that
arc
lcs
s re
spon
sive
(e.
g.
Ano
lis,
Phrj
mos
oma,
X
anlu
sia)
. S
uch
a re
latio
nshi
p is
an
tici
pate
d as
ana
crob
ic m
etab
olis
m p
rovi
des
thc
met
abol
ic b
asis
of'
thc
rapi
d ac
tivity
. O
n th
e av
erag
e, s
mal
l li
zard
s ha
ve a
naer
obic
sco
pes
of
appr
oxim
atel
y 0.
8 m
g la
ctat
e/(g
mas
s x
30 s
). T
hesc
dat
a sh
own
no s
ix
depe
nden
ce o
f an
aero
bic
scop
e (T
able
VII
; r=
O.
1, P
> 0
.5).
Pre
sum
ably
AL
BE
RT
F.
BE
NN
ET
T
TABLE
VII
M
axim
al a
naer
obic
sco
pe o
f sm
all
rept
iles
and
amph
ibia
ns
Spec
ies
Rep
tiles
A
nolis
car
olin
ensi
s D
ipso
saur
us d
orsa
lis
Ner
odia
sip
edon
' Ph
r~'n
osom
a pla
tyrh
inos
Sc
elop
orus
occ
iden
talis
U
ta s~
ansb
uria
na
Xan
fusi
a vi
gilis
A
mph
ibia
ns
Ane
ides
jlav
ipun
ct a
rus
Ane
ides
lug
ubri
s B
arra
chos
eps
affe
nuaf
us
Bri
fo b
orea
s C
eotr
yper
es se
raph
inii
Hyl
a re
gilla
N
otop
hr h
alm
us v
irid
esce
ns
Ran
a ca
tesb
eian
a ta
dpol
es
Ran
a pi
pien
s
Mas
s
Rat
e of
lact
ate
acid
for
mat
ion
mg
lact
ate/
(g
mas
s x 3
0 s)
R
efer
ence
Ben
nett
and
Lic
ht,
1972
B
enne
tt a
nd L
icht
, 19
72
Poug
h, 1
978
Ben
nett
and
Lic
ht,
1972
B
enne
tt a
nd R
uben
, 19
75
Ben
nett
and
Lic
ht,
1972
B
enne
tt a
nd L
icht
, 19
72
Ben
nett
and
Lic
ht,
1974
B
enne
tt an
d L
icht
, 19
74
Ben
nett
and
Lic
ht,
1974
B
enne
tt a
nd L
icht
, 19
74
Ben
nett
and
Wak
e, 1
974
Ben
nett
and
Lic
ht,
1974
B
enne
tt a
nd L
icht
, 19
74
Ben
nett
and
Lic
ht,
1974
B
enne
tt a
nd L
icht
, 19
74
diff
eren
t be
havi
oral
res
pons
es o
verw
helm
any
mas
s-sp
ecif
ic t
rend
s, s
uch
as
thos
e ex
pect
ed o
n th
e ba
sis
of d
iffe
rent
ial
mus
cula
rity
. F
ew c
ompa
rati
ve
data
exi
st fo
r oth
er g
roup
s of
ver
tebr
ates
and
thus
it is
dif
ficu
lt to
pla
ce th
ese
scop
es in
a b
road
er c
ompa
rati
ve f
ram
ewor
k. T
he
scop
es a
re c
lear
ly g
reat
er
than
tho
se o
f mos
t am
phib
ians
(T
able
VII
), w
hich
ran
ge m
ore
wid
ely.
Th
e gr
eate
st s
cope
s fo
r am
phib
ians
(B
atra
chos
eps,
Ran
a) a
re e
quiv
alen
t to
the
lo
wes
t on
es f
or r
epti
les.
The
se d
iffe
renc
es a
re p
roba
bly
not
attr
ibut
able
to
diff
eren
tial
of
body
tem
pera
ture
, as
ana
erob
ic s
cope
has
a l
ow t
herm
al
depe
nden
ce in
the
rep
tile
s (s
ee b
elow
) an
d th
e am
phib
ian
tem
pera
ture
s ar
e en
viro
nmen
tall
y re
alis
tic.
Th
e ra
te o
f ac
tiva
tion
of
the
rept
ilia
n an
aero
bic
resp
onse
app
ears
par
ticu
larl
y hi
gh.
3. A
naer
obic
Cap
acit
y T
able
VII
I pr
esen
ts t
he t
otal
am
ount
of
lact
ic a
cid
form
ed d
urin
g lo
nger
-ter
m
acti
vity
as
the
diff
eren
tial
bet
wee
n po
stac
tive
and
re
stin
g
TA
~L
E
VII
I
Max
imal
ana
erob
ic c
apac
i~y in
sm
all
repf
iles*
Spe
cies
Dur
atio
n L
acti
c ac
id f
orm
ed
of
mass
T
B
duri
ng a
ctiv
ity
acti
vity
--
g "c
m
g/g
mas
s m
in
Ref
eren
ce
Tes
tudi
nes
Pseu
dem
ys s
crip
fa
Terr
apen
e or
nara
S
auri
a A
rrol
is c
arol
inen
sis
Dip
sosa
urus
dor
salis
Lu
mec
es o
bsol
efus
Ph
ryno
som
a pl
afyr
hino
s Sr
elop
orus
occ
iden
ialis
Sc
ince
lla l
afer
alis
U
ia sr
ansb
uria
na
Xan
rusi
a vi
gilis
S
erpe
ntes
C
rora
lus
viri
dis
iMas
rico
phis
~age
lltrm
an
d C
olub
er c
onsr
ricr
or c
ombi
ned
Lich
anur
a rr
iorr
gara
N
ernd
ia r
hom
brfe
ra
Ner
odia
srp
edon
Th
amno
phis
sirr
alis
Gat
ten,
197
4 G
atte
n. 1
974
Ben
nett
and
Lic
ht,
1972
B
enne
tt a
nd D
awrs
on,
1972
A
. F
. Ben
nett
and
W.
R.
Daw
son,
unp
ubli
shed
B
enne
tt a
nd L
icht
, 19
72
Ben
nett
and
Gle
eson
, 19
76
Ben
nett
and
Lic
ht,
1972
B
enne
tt a
nd L
icht
, 19
72
Ben
nett
and
Lic
ht,
1972
Rub
en,
1976
R
uben
. 19
76
Rub
en,
1976
G
ratz
and
Hut
chis
on,
1977
P
ough
, 19
78
Pou
gh,
1977
+ .M
easu
red
as l
acta
te f
orm
ed d
urin
g 2+
m
in o
f in
tens
e ac
tivi
ty
" E
stim
ated
fro
m b
lood
lac
tate
.
182
AL
BE
RT
F.
BE
NN
ET
T
lact
ate
cont
ents
(ana
erob
ic c
apac
ity).
Th
e an
aero
bic
capa
citie
s of
snak
es a
nd
liza
rds
are
broa
dly
over
lapp
ing.
Spe
cies
with
the
gre
ates
t po
tent
ial
activ
ity
leve
ls d
urin
g ac
tivity
(D
ipso
saur
us, M
astic
ophi
s, N
erod
ia,
Scel
opor
us)
have
th
e hi
ghes
t an
aero
bic
capa
citie
s.
Th
e tw
o tu
rtle
sp
ecie
s ex
amin
ed
accu
mul
ate
subs
tant
iall
y le
ss l
acta
te d
urin
g ac
tivi
ty t
han
do t
he o
ther
re
ptil
es. T
hese
low
con
cent
rati
ons
cont
rast
to
the
very
gre
at p
rodu
ctio
n of
la
ctic
aci
d du
ring
forc
ed d
ivin
g in
tur
tles
(R
obin
et a
l., 1
964;
Pen
ny,
1974
). L
ong-
term
an
aero
bic
ener
gy g
ener
atio
n an
d to
lera
nce
do n
ot i
ndic
ate
capa
city
for a
naer
obic
act
ivit
y (B
enne
tt,
1978
). T
he
mas
s-sp
ecif
ic a
naer
obic
ca
paci
ties
of
the
spec
ies
liste
d in
Tab
le V
III
do n
ot s
how
a s
igni
fica
nt s
ize
depe
nden
ce:
r=0.
5 (P
> 0
.4)
for
liza
rds
and
r=0.
28 (
P>
0.5
) fo
r all
rept
iles
[l
og (m
g la
ctat
elg
mas
s) v
ersu
s lo
g m
ass]
. A
s is
the
case
for a
naer
obic
sco
pe,
beha
vior
al ty
pe is
a m
ore
impo
rtan
t det
erm
inan
t of
ana
erob
ic c
apac
ity
than
is
bod
y si
ze p
er s
e.
Th
e an
aero
bic
capa
citie
s of
rep
tile
s ar
e ge
nera
lly g
reat
er t
han
thos
e of
am
phib
ians
, bu
t th
e di
ffer
entia
l is
muc
h sm
alle
r th
an t
hat
for
anae
robi
c sc
opes
. A
naer
obic
cap
acit
ies
of
18 s
peci
es o
f am
phib
ians
(at
15
-2V
C,
Ben
nett
and
Lic
ht,
1972
; Hut
chis
on a
nd M
ille
r, 1
979)
ran
ge f
rom
0.2
9 (N
otop
thal
mus
) to
1.77
(Xen
opus
) mg
lact
atel
g m
ass
and
aver
age
0.88
mgl
g.
Th
is m
ay b
e co
mpa
red
with
an
aver
age
of 1
.21
mg/
g fo
r th
e 16
spe
cies
of
rept
iles
rep
orte
d in
Tab
le V
III.
Alt
houg
h th
e ra
nges
ove
rlap
bro
adly
and
so
me
amph
ibia
ns h
ave
very
hig
h an
aero
bic
capa
citie
s, t
he m
ean
valu
es o
f th
ese
grou
ps a
re s
igni
fica
ntly
dif
fere
nt (
P<
0.0
5, S
tude
nt's
t-t
est)
. A
naer
o-
bic
capa
citi
es o
f the
rode
nts
Mic
rotu
s m
ontu
nus a
nd D
ipod
omys
mer
rium
i are
0.
76 a
nd 0
.51
mg/
g re
spec
tivel
y (R
uben
and
Bat
tali
a, 1
979)
, sub
stan
tial
ly
low
er t
han
thos
e of
mos
t sn
akes
and
liz
ards
. R
epti
les
as a
gro
up h
ave
a gr
eate
r po
tent
ial
to u
tili
ze a
naer
obic
met
abol
ism
dur
ing
activ
ity t
han
do th
e am
phib
ians
and
mam
mal
s in
vest
igat
ed t
hus
far.
4. T
herm
al D
epen
denc
e of
Ana
erob
ic M
etab
olis
m
Th
e th
erm
al
depe
nden
ce o
f an
aero
bic
ener
gy
gene
rati
on,
of
both
an
aero
bic
scop
e an
d an
aero
bic
capa
city
, is
sub
stan
tial
ly l
ess
than
tha
t of
ae
robi
c m
etab
olis
m a
nd i
s le
ss t
han
that
ant
icip
ated
for
bio
logi
cal r
eact
ion
rate
s in
gen
eral
. F
igur
e 8
show
s an
aero
bic
scop
e as
a f
unct
ion
of b
ody
tem
pera
ture
of t
hree
liza
rds.
At t
empe
ratu
res
abov
e 20
°C, Q
o va
lues
for t
he
max
imal
rat
e of
lac
tic a
cid
prod
ucti
on r
ange
bet
wee
n 1.
1 an
d 1.
3 fo
r th
ese
spec
ies,
con
side
rabl
y le
ss th
an t
hose
of
2-3
norm
ally
ant
icip
ated
. A
t lo
wer
te
mpe
ratu
res,
ana
erob
ic s
cope
and
bur
st a
ctiv
ity c
apac
ity d
ecli
ne. A
naer
o-
bic
capa
city
has
a s
imila
rly
low
the
rmal
dep
ende
nce
(Tab
le I
X)
with
QU
valu
es r
angi
ng f
rom
0.7
6 to
1.3
9. T
he
ther
mal
dep
ende
nce
of p
eak
bloo
d la
ctic
aci
d le
vels
fol
low
ing
acti
vity
is
also
low
in
the
liza
rds
Igua
na i
guan
a (M
ober
ly,
1968
a) a
nd
Am
blyr
hync
hus
cris
tatu
s (B
enne
tt
et
al.,
1975
),
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
18
3
20
30
Bod
y te
mpe
ratu
re P
C)
FIG.
8. A
naer
obic
sc
ope
as a
fun
ctio
n of
tem
pera
ture
in
thr
ce l
izar
ds (
Ano
lrr
caro
lrne
ns~r
, Ura
sr
ansb
urra
na, X
anlu
sia
vigi
lis).
Th
e sh
aded
rcg
ion
indi
cate
s va
lucs
ant
icip
ated
on
thc
basis
ofQ
lo v
aluc
s of
2 (u
ppcr
bou
nd) a
nd 3
(low
cr b
ound
) of a
n an
aero
bic
scop
e of
1.0
mg
lact
atc/
(g x
30
s) at
40°
C. D
ara
from
Bcn
nett
and
Lic
ht (
1972
), an
d C
ouls
on (
1979
) fo
r A
nolis
at
28°C
(opc
n sq
uarc
).
indi
cati
ng te
mpe
ratu
re-i
ndep
ende
nt a
naer
obic
cap
acit
ies
in th
ese
lizar
ds a
s w
ell.
Th
is t
herm
ally
ind
epen
dent
met
abol
ism
per
mit
s th
ese
anim
als
to
perf
orm
ove
r a b
road
ran
ge o
f bod
y te
mpe
ratu
res.
Rap
id a
ctiv
ity
and
esca
pe
beha
vior
are
pos
sibl
e by
mea
ns o
f an
aero
bic
met
abol
ism
eve
n at
tem
pera
- tu
res
15-2
0°C
be
low
sel
ecte
d th
erm
al l
evel
s.
Th
e in
flue
nce
of t
empe
ratu
re o
n re
ptil
ian
beha
vior
al p
erfo
rman
ce h
as
been
exa
min
ed i
n on
ly a
few
inst
ance
s. I
n ge
nera
l, th
e th
erm
al d
epen
denc
e of
thi
s pe
rfor
man
ce is
sim
ilar
to
that
of
anae
robi
c m
etab
olis
m a
nd is
low
er
than
no
rmal
ly
anti
cipa
ted
(&,=
2-3)
. T
he
max
imal
st
riki
ng s
peed
of
goph
er s
nake
s (P
ituo
phis
mel
anol
eucu
s) h
as a
Q,o
of 1
.4 o
ver
the
rang
e of
18
-27°
C
(Gre
enw
ald,
19
74).
Th
e nu
mbe
r of
lim
b m
ovem
ents
pos
sibl
e be
fore
exh
aust
ion
is t
empe
ratu
re i
ndep
ende
nt f
rom
25
to 4
0°C
in m
arin
e ig
uana
s (A
mbl
yrhy
nchu
s cr
ista
tus;
Ben
nett
et
al.,
1975
). B
urst
spe
eds
and
dist
ance
ru
nnin
g ca
paci
ties
ar
e es
sent
ially
te
mpe
ratu
re
inde
pend
ent
(.Qla
=0.7
-1.5
) be
twee
n 30
and
40°
C in
six
spe
cies
of l
izar
ds (C
nem
idop
horu
s m
urin
us, D
ipso
saur
us d
orsa
lis, E
umec
es o
bsol
etus
, Ger
rhon
otus
mul
ticar
inat
us,
Scel
opor
us o
ccid
enta
lis,
Um
a no
tatn
; B
enne
tt,
1980
). I
n th
e la
tter
fou
r sp
ecie
s, th
ese
acti
viti
es h
ave Q
lo va
lues
of o
nly
1.4-
1.9
betw
een
20 a
nd 3
0°C
.
AL
BE
RT
F.
BE
NN
ET
T
Ther
mal
dep
ende
nce
of a
naer
obic
cap
acitj
1 of
rept
iles
Tem
pera
ture
ra
nge
Spec
ies
"C
QIO R
efer
ence
Terr
apen
e or
nata
3MO
0.76
Gat
ten,
1974
Ano
lis c
arol
inen
sis
20-37
1.09
Ben
nett
and
Lic
ht, 1972
Dip
sosa
urus
dor
salis
25-40
1.39
Ben
nett
and
Daw
son,
1972
Eurn
eces
obs
olet
us
2MO
1.36
B
enne
tt a
nd D
awso
n, u
npub
. da
ta
Scin
cella
lat
eral
is
12-30
0.87
Ben
nett
and
Lic
ht, 1972
Scel
opor
us o
ccid
enta
lis
20-35
1.26
Ben
nett
and
Gle
eson
, 1976
Uta
stan
sbur
iana
20-37
1.00
Ben
nett
and
Lic
ht, 1972
Xan
tusi
a zi
@lis
12-30
1.08
Ben
nett
and
Lic
ht, 1972
Ner
odia
rho
mbi
fera
15-35
1.34
G
ratz
and
Hut
chis
on, 1977
Whe
ther
lac
tic
acid
pro
duct
ion
is t
he b
asis
for
all
thes
e pe
rfor
man
ce
char
acte
rist
ics
is n
ot k
now
n, b
ut i
ts in
volv
emen
t is
like
ly. T
he
low
the
rmal
de
pend
ence
of
th
ese
beha
vior
s is
ce
rtai
nly
of
cons
ider
able
ec
olog
ical
si
gnif
ican
ce.
5. O
ther
Fac
tors
Afe
ctin
g A
naer
obic
Met
abol
ism
U
ndou
bted
ly s
ever
al a
ddit
iona
l fa
ctor
s be
side
s be
havi
oral
typ
e an
d bo
dy
tem
pera
ture
inf
luen
ce t
he c
apac
ity
and
scop
e of
ana
erob
ic m
etab
olis
m.
As
stat
ed p
revi
ousl
y, a
naer
obic
sco
pe a
nd c
apac
ity
are
appa
rent
ly in
depe
nden
t of
bod
y si
ze in
sm
all r
epti
les
(Cou
lson
, 19
79),
at l
east
judg
ing
on th
e ba
sis
of
the
very
few
dat
a av
aila
ble.
How
ever
, a
muc
h la
rger
siz
e ra
nge
is r
equi
red
befo
re w
e m
ay h
ave
conf
iden
ce i
n th
is c
oncl
usio
n. S
uch
vari
able
s as
tim
e of
da
y, s
tage
of d
evel
opm
ent,
accl
imat
ory
and
seas
onal
sta
tes,
and
sex
aff
ect t
he
aero
bic
met
abol
ic le
vels
of
rept
iles
(B
enne
tt a
nd D
awso
n, 1
976)
, but
we
do
no
t kn
ow t
he i
nflu
ence
of
thes
e va
riab
les
on a
naer
obic
met
abol
ism
. D
iel
cycl
es h
ave
been
dem
onst
rate
d to
inf
luen
ce t
he a
naer
obic
cap
acit
y of
the
sn
ake
Ner
odia
rho
mbi
fera
, with
a 4
0% d
ecre
men
t occ
urri
ng a
t nig
ht (
Gra
tz
and
Hut
chis
on,
1977
)) b
ut n
o ot
her
spec
ies
has
been
exa
min
ed.
Bot
h an
aero
bic
capa
city
and
dur
atio
n of
act
ivit
y in
crea
se d
urin
g on
toge
ny in
the
sn
akes
Tha
mno
phis
sir
tali
s an
d N
erod
ia. s
iped
on (
Pou
gh,
1977
, 19
78).
Suc
h m
ajor
cha
nges
dur
ing
mat
urat
ion
as a
50%
incr
ease
in a
naer
obic
cap
acit
y an
d a
four
- to
sev
enfo
ld
incr
emen
t in
ti
me
to e
xhau
stio
n m
ust
have
pr
ofou
nd e
colo
gica
l and
beh
avio
ral
cons
eque
nces
for
thes
e sp
ecie
s. A
naer
o-
bic
scop
e an
d ca
paci
ty a
re u
naff
ecte
d by
the
alt
itud
e of
the
test
sit
e or
pri
or
resi
denc
e in
the
liz
ard
Scel
opor
us o
ccid
enta
lis,
the
geog
raph
ical
ran
ge o
f w
hich
ext
ends
ove
r a
broa
d al
titu
dina
l gr
adie
nt (B
enne
tt a
nd R
uben
, 19
75).
3. T
HE
EN
ER
GE
T~
CS
OF
RE
PT
~L
~A
N
AC
T~
V~
TY
18
5
Th
e in
flue
nce
of th
ese
and
othe
r fa
ctor
s re
quir
es m
uch
furt
her e
xam
inat
ion
and
shou
ld c
onst
itut
e a
rew
ardi
ng f
ield
of
rese
arch
in
the
futu
re.
IV.
To
tal
Met
abo
lic
Po
wer
In
pu
t: T
he
Cap
acit
ies
of A
erob
ic a
nd
A
nae
rob
ic E
ner
get
ics
Th
e re
lativ
e co
ntri
buti
on o
f aer
obic
and
ana
erob
ic m
etab
olis
m to
act
ivity
en
erge
tics
may
be
esti
mat
ed b
y ca
lcul
atin
g th
e ne
t yi
eld
of h
igh
ener
gy
phos
phat
e co
mpo
unds
form
ed d
urin
g a
beha
vior
al s
eque
nce.
Sim
ulta
neou
s m
easu
rem
ents
of
oxyg
en c
onsu
mpt
ion
and
lact
ic a
cid
form
atio
n du
ring
ac
tivity
pe
rmit
an
ev
alua
tion
of
thei
r re
lativ
e im
port
ance
in
en
ergy
ut
iliza
tion.
The
se r
elat
ions
hips
are
usu
ally
est
imat
ed w
ith t
he f
ollo
win
g fo
rmul
as
1.0
ml0
2 (S
TP
D)
cons
umed
= 2
90 p
mol
es A
TP
1.
0 m
g la
ctic
aci
d fo
rmed
= 1
6.7
pmol
es A
TP
(Ben
nett
and
Lic
ht,
1972
). T
hese
equ
atio
ns a
ssum
e ne
t yi
elds
of
39 a
nd
3 A
TP
mol
ecul
es p
er g
lyco
gen
unit
via
aer
obic
and
ana
erob
ic m
etab
olis
m
resp
ectiv
ely.
Th
e fo
rmer
val
ue m
ay o
vere
stim
ate
aero
bic
AT
P p
rodu
ctio
n by
5%
due
to
unce
rtai
ntie
s in
the
AT
P y
ield
of
carb
ohyd
rate
cat
abol
ism
. T
he
fuel
is
assu
med
to
be g
lyco
gen,
as
the
depl
etio
n of
mus
cle
glyc
ogen
is
mor
e th
an a
dequ
ate
to a
ccou
nt f
or t
he f
orm
atio
n of
all
mus
cle
lact
ic a
cid
in
Igua
na
igua
na
(Mob
erly
, 19
68a)
and
N
erod
ia
rhom
bife
ra
(Gra
tz a
nd
Hut
chis
on,
1977
).
Max
imal
ra
tes
of
AT
P f
orm
atio
n in
ea
ch
met
abol
ic
mod
e ca
n be
ca
lcul
ated
by
com
pari
ng m
axim
al a
erob
ic a
nd a
naer
obic
sco
pes.
Ave
rage
va
lues
of t
hese
fact
ors
for
smal
l liz
ards
are
est
imat
ed a
s 2.
2 m
l Oz/
(g x
h) a
t 40
°C f
or a
10-
g liz
ard
(Tab
les
I and
111
) and
0.8
mg
lact
ate/
(g x
30
s) (T
able
V
II).
Th
e ae
robi
c an
d an
aero
bic
scop
es a
re e
qual
to
10.7
and
26.
7 pm
oles
A
TP
/min
res
pect
ivel
y. F
or i
ndiv
idua
l sp
ecie
s in
whi
ch b
oth
fact
ors
have
be
en m
easu
red,
aer
obic
and
ana
erob
ic s
cope
s ar
e 10
.9 a
nd 2
8.4
pmol
es
AT
P/m
in i
n D
ipso
saur
us d
orsa
lis a
nd 6
.4 a
nd 3
5.7
pmol
es A
TP
/min
in
Scel
opor
us o
ccid
enta
lis r
espe
ctiv
ely
(Ben
nett
and
Lic
ht,
1972
; Ben
nett
and
Daw
son,
19
72;
Ben
nett
and
Rub
en,
1975
; B
enne
tt a
nd G
lees
on,
1976
). T
hese
scop
es a
re n
ot n
eces
sari
ly a
ttai
ned
unde
r th
e sa
me
cond
ition
s or
at t
he
sam
e bo
dy t
empe
ratu
re.
How
ever
, th
ey i
ndic
ate
clea
rly
that
the
cat
abol
ic
and
AT
P-ge
nera
ting
ab
ilitie
s of
ana
erob
ic s
yste
ms
can
exce
ed t
hose
of
aero
bic
syst
ems
by a
fac
tor
of 2
-5
on a
rat
e ba
sis.
The
se c
ompa
riso
ns
indi
cate
that
ana
erob
ic m
etab
olis
m i
n re
ptil
es c
an b
e m
ore
effi
cien
t at A
TP
pr
oduc
tion
pe
r un
it t
ime
than
can
aer
obic
met
abol
ism
. B
ecau
se o
f th
e in
effi
cien
cy o
f an
aero
bios
is o
n an
A'I'
P-pe
r-su
bstr
ate
basi
s, t
he d
iff'e
rent
ial
in c
arbo
hydr
ate
utili
zatio
n by
the
se p
athw
ays
is m
uch
grea
ter;
app
roxi
-
186
AL
BE
RT
F.
BE
NN
ET
T
mat
ely
9S0/
, of
the
car
bohy
drat
e is
cat
abol
ized
an
aero
bica
lly
(Ben
nett
et
al.
, 19
75).
Thu
s, i
n te
rms
of f
uel
util
izat
ion
duri
ng i
nten
se a
ctiv
ity
in
rept
iles
, an
aero
bios
is is
far
mor
e si
gnif
ican
t th
an a
erob
iosi
s.
Th
e ac
tual
con
trib
utio
n of
aer
obic
and
ana
erob
ic e
nerg
etic
s to
an
acti
vity
se
quen
ce w
ill d
epen
d up
on t
he in
tens
ity
and
dura
tion
of t
he b
ehav
ior.
Low
le
vel
acti
vity
w
ill
be s
uppo
rted
ae
robi
cally
, af
ter
an
init
ial
peri
od
of
anae
robi
osis
ref
lect
ing
a la
g in
the
dev
elop
men
t of a
ctiv
e ox
ygen
con
sum
p-
tion.
If
the
activ
ity i
s su
stai
nabl
e ae
robi
call
y, th
e lo
nger
the
dura
tion
of t
he
acti
vity
, th
e sm
alle
r is
the
rel
ativ
e co
ntri
buti
on o
f th
e in
itia
l an
aero
bic
com
pone
nt. A
s in
tens
ity
of a
ctiv
ity
incr
ease
s, i
ts d
urat
ion
befo
re e
xhau
stio
n de
crea
ses,
and
bo
th
thes
e fa
ctor
s w
ill
incr
ease
the
rel
ativ
e an
aero
bic
cont
ribu
tion
to
the
activ
ity.
Th
e co
ntri
buti
on o
f ae
robi
c an
d an
aero
bic
met
abol
ism
to
the
supp
ort
of i
nten
se e
scap
e ac
tivity
of
2-10
m
in d
urat
ion
have
bee
n es
tim
ated
for
sev
eral
spe
cies
of
rept
iles
(T
able
X).
Ana
erob
ic
met
abol
ism
acc
ount
s fo
r 50
-75%
of
the
tota
l A
TP
pro
duct
ion
duri
ng th
is
inte
nse
acti
vity
. Th
e ti
me
peri
ods
cons
ider
ed i
n th
e ac
tivity
sum
mar
ized
in
Tab
le X
rep
rese
nt r
athe
r lo
ng b
ehav
iora
l pe
rfor
man
ce a
nd o
ften
res
ult
in
exha
usti
on.
Inte
nse
activ
ity
of
shor
ter
dura
tion
ha
s an
ev
en
grea
ter
anae
robi
c re
lianc
e, a
s th
e ra
te o
f lac
tic a
cid
prod
ucti
on i
s hi
ghes
t dur
ing
the
initi
al s
tage
s of a
ctiv
ity a
nd a
ctiv
e ox
ygen
con
sum
ptio
n re
quir
es ti
me
for f
ull
deve
lopm
ent.
A
naer
obic
m
etab
olis
m
is
esti
mat
ed
to
prov
ide
at
leas
t 80
-90%
of
the
tota
l A
TP
pro
duce
d du
ring
the
firs
t 30
s of
act
ivit
y in
sm
all
liza
rds
(Ben
nett
and
Lic
ht,
1972
).
Bod
y te
mpe
ratu
re e
xert
s a
stro
ng in
flue
nce
on t
he to
tal
met
abol
ic p
ower
in
put
to a
ctiv
ity
and
on t
he r
elat
ive
impo
rtan
ce o
f ae
robi
c an
d an
aero
bic
supp
ort
of t
hat
activ
ity.
Mos
t of
the
mea
sure
men
ts r
epor
ted
in T
able
X
wer
e m
ade
at h
igh
tem
pera
ture
s, a
t w
hich
the
aer
obic
con
trib
utio
n is
m
axim
al.
As
tem
pera
ture
dec
line
s, t
otal
met
abol
ic p
ower
inp
ut d
ecre
ases
. H
owev
er,
the
aero
bic
cont
ribu
tion
dec
reas
es m
ore
rapi
dly
than
doe
s th
e an
aero
bic;
the
Qo ra
nges
are
2-3
an
d 1-
1.5
resp
ectiv
ely.
Con
sequ
entl
y,
anae
robi
osis
pro
vide
s an
eve
n gr
eate
r sh
are
of t
he e
nerg
etic
sup
port
for
in
tens
e ac
tivity
at l
ow b
ody
tem
pera
ture
s. T
he
ther
mal
dep
ende
nce
of th
ese
aspe
cts
of e
nerg
y su
ppor
t to
vig
orou
s ac
tivi
ty i
n th
e liz
ard
Dip
sosa
uvus
do
rsal
is i
s sh
own
in F
ig.
9. M
etab
olic
pow
er i
nput
is
max
imal
at
40°C
, th
e fi
eld
acti
vity
tem
pera
ture
of
this
ani
mal
, at
whi
ch a
naer
obio
sis
prov
ides
58
Yb
of A
TP
for
mat
ion.
Th
e re
lati
ve c
ontr
ibut
ion
of t
his
com
pone
nt
incr
ease
s w
ith d
ecre
asin
g te
mpe
ratu
re a
nd i
s 83
% a
t 25
°C.
Bod
y si
ze m
ay a
lso
be e
xpec
ted
to in
flue
nce
the
rela
tive
cont
ribu
tion
s of
ae
robi
c an
d an
aero
bic
met
abol
ism
to
acti
vity
. Mas
s-sp
ecif
ic a
erob
ic f
acto
rs
(res
ting
and
max
imal
oxy
gen
cons
umpt
ion
and
aero
bic
scop
e) d
ecli
ne a
s bo
dy m
ass
incr
ease
s, a
ppro
xim
atel
y pr
opor
tion
ally
to
m-0
2'.
If
ana
erob
ic
scop
e an
d/or
cap
acity
are
ind
epen
dent
of
body
mas
s, a
naer
obic
fac
tors
Th
e c
on
trib
uti
on
of
aero
bic
and
ana
erob
ic e
ncrg
eric
s to
inte
nse
acti
viry
in
rep
rile
sX
Aer
obic
A
naer
obic
T
otal
D
urat
ion
of
TB
-
Perc
enta
ge
Act
ivity
-
pmol
es
po
les
p
ole
s
anae
robi
c Sp
ecie
s "C
A
TP
/g
AT
P/g
A
TP
/g
cont
ribu
tion
rn
in
Ref
eren
ce
Ter
rup
ene
orn
a~
a
40
6.2
7.5
13.7
55
2
Gat
ten,
197
4 A
mb
lyrh
ynch
us
cris
ratu
s 40
6.
3 22
.1**
28
.4
78
2 B
enne
tt e
t a
l.,
1975
D
ipsn
suur
us d
orsa
lis
40
21.9
30
.3
52.2
58
2
Ben
nett
and
Daw
son,
197
2 E
umec
es u
bsol
etus
40
20
.2
19.7
39
.9
49
2 B
enne
tt a
nd D
awso
n, u
npub
lish
ed
Igu
un
u i
gu
ana
3 5
9.1
16.2
25
.3
64
5 M
ober
ly,
1968
a;
Ben
nett
and
Lic
ht,
1972
P
seud
emys
scr
ipla
30
5.
9 9.
2 15
.1
6 1
2 G
atte
n. 1
974
Sce
lopo
rus
orc
iden
~uli
s 30
10
.8
28.8
39
.6
73
2 B
enne
tt a
nd G
lees
on,
1976
C
rort
~lu
s cir
ldis
35
10
.6
16.2
26
.8
60
5 R
uben
, 19
76
Lic
lrt~
nu
ru tr
rvir
ga
~a
32
4.
6 5.
0xx
9.6
52
5 R
uben
, 19
76
Ma
s~
ico
~h
is~
fla
ge
llu
m,
35
23.0
29
.1
52.1
56
5
Rub
en,
1976
C
olu
ber
con
rrri
cror
N
cro
dia
rho
rnbf
cra
25
9.1
30.2
39
.3
77
10
Gra
tz a
nd H
utch
ison
, 19
77
* X
leas
ured
at
the
body
tem
per
ature
at
whi
ch t
he g
reat
est
tota
l m
etab
olic
pow
er i
nput
occ
urs.
**
Est
imat
ed f
rom
blo
od l
acta
te c
once
ntra
tion
.
AL
BE
RT
F.
BE
NN
ET
T
"
25
30
35
40
4
5
Bod
y te
mp
erat
ure
(OC)
FIG. 9. D
ipso
saur
usdo
rsal
rs.
met
abol
ic p
ower
inpu
t (ae
robi
c, a
naer
obic
, and
tota
l) du
ring
2 m
in o
f bur
st
activ
ity a
s a
func
tion
of b
ody
tem
pera
ture
. Rcd
raw
n fr
om B
enne
tt a
nd D
awso
n (1
972)
.
shou
ld a
ssum
e a
grea
ter
sign
ific
ance
in
supp
orti
ng b
urst
act
ivity
in
larg
er
anim
als
(Cou
lson
, 19
79).
Con
vers
ely,
aer
obic
fac
tors
wou
ld
assu
me
a gr
eate
r si
gnif
ican
ce in
sm
alle
r an
imal
s. H
owev
er,
the
assu
mpt
ions
beh
ind
mas
s-in
depe
nden
ce o
f an
aero
bic
met
abol
ic a
bili
ties
hav
e no
t be
en t
este
d ov
er a
larg
e m
ass
rang
e, a
nd t
hese
spe
cula
tion
s ar
e on
ly p
resu
mpt
ive
unti
l su
ch m
easu
rem
ents
are
mad
e.
Tot
al m
etab
olic
pow
er i
nput
, th
e su
m o
f th
e ae
robi
c an
d an
aero
bic
com
pone
nts,
is
gene
rally
cor
rela
ted
with
act
ivit
y ca
paci
ty a
mon
g di
ffer
ent
grou
ps o
f rep
tile
s (T
able
X).
Sm
all l
izar
ds a
nd d
iurn
ally
act
ive
snak
es (e
.g.
Dip
sosa
urus
, E
umec
es,
Mas
ticop
his,
Ner
odia
, Sc
elop
orus
) ha
ve t
he g
reat
est
leve
ls o
f tot
al p
ower
inpu
t. T
urtl
es a
nd b
oiid
sna
kes
(Lic
hanu
ra, P
seud
emys
, T
erra
pene
) ha
ve c
orre
spon
ding
ly l
ow m
etab
olic
cap
aciti
es.
Lit
tle
com
para
tive
in
form
atio
n is
av
aila
ble
for
max
imal
m
etab
olic
su
ppor
t of
int
ense
, sh
ort-
term
ac
tivi
ty i
n ot
her
vert
ebra
te g
roup
s. T
otal
m
etab
olic
inpu
t du
ring
2-3
m
in o
f act
ivit
y in
fou
r sp
ecie
s of
am
phib
ians
at
20-2
5°C
ra
nges
fro
m 1
4 to
31
pmol
es A
TP
/g m
ass
(Ben
nett
and
Lic
ht,
1973
; Hil
lman
et
al.,
1979
). T
he
high
est
valu
es d
o no
t eq
ual
thos
e of
the
m
ost
activ
e re
ptile
s,
but
few
sp
ecie
s ha
ve
been
ex
amin
ed.
Sim
ilar
m
easu
rem
ents
on
the
ener
geti
cs o
f bu
rst
activ
ity o
f m
amm
als
and
bird
s w
ould
be
of
cons
ider
able
int
eres
t, as
the
se a
nim
als
have
suc
h gr
eatl
y
3. T
HE
EN
ER
GE
TIC
S O
F R
EPT
II.I
AN
A
CT
IVIT
Y
189
expa
nded
aer
obic
cap
acit
ies.
Mea
sure
men
ts b
ased
on
max
imal
oxy
gen
cons
umpt
ion
are
inap
plic
able
to
this
com
pari
son,
be
caus
e th
ese
leve
ls
cann
ot b
e in
stan
tane
ousl
y at
tain
ed.
Th
e on
ly o
bser
vati
ons
avai
labl
e ar
e th
ose
for
the
rode
nts
Dip
odom
ys m
erri
ami
and
Mic
rotu
s m
onta
nils
, w
hich
pr
oduc
e 10
7 an
d 53
pm
oles
AT
P/g
res
pect
ivel
y du
ring
5 m
in o
f m
axim
al
acti
vity
(R
uben
and
Bat
tali
a, 1
979)
. Ana
erob
ic m
etab
olis
m a
ccou
nts
for
8 an
d 25
% r
espe
ctiv
ely
ofth
e to
tal p
rodu
ctio
n. A
ltho
ugh
thes
e to
tal v
aluc
s fo
r m
axim
al a
ctiv
ity
exce
ed t
hose
of
mos
t re
ptil
es,
they
are
not
an
orde
r of
m
agni
tude
in
exce
ss a
s ar
e th
eir
aero
bic
capa
bili
ties
. D
urin
g sh
orte
r ti
me
peri
ods,
whe
n ae
robi
osis
is le
ss s
igni
fica
nt, m
etab
olic
pow
er in
put t
o ac
tivity
in
rep
tile
s m
ay e
qual
or
exce
ed t
hat o
f sm
all m
amm
als.
Th
e de
velo
pmen
t of
high
aer
obic
cap
acit
ies
in m
amm
als
has
not
resu
lted
in
incr
ease
d ca
paci
ties
for
burs
t ac
tivi
ty,
but
rath
er in
the
exp
ansi
on o
f ca
paci
tics
for
rou
tine
and
su
stai
nabl
e ac
tivi
ty (
Rub
en a
nd B
atta
lia,
197
9; B
enne
tt a
nd R
ubcn
, 19
79).
V.
Met
abo
lic
Rat
e u
nd
er N
atu
ral
Cir
cum
stan
ces
Ana
erob
ic
met
abol
ism
si
gnif
ican
tly
exte
nds
the
beha
vior
al
scop
e of
re
ptil
es,
as a
erob
ic l
imit
s ar
e lo
w i
n th
ese
anim
als.
How
ever
, it
s us
e is
co
rrel
ated
wit
h di
min
ishe
d be
havi
oral
cap
acit
y an
d ex
haus
tion
, an
d it
is
anti
cipa
ted
that
re
ptil
es
wou
ld
avoi
d an
aero
bios
is
if po
ssib
le.
It
is
anti
cipa
ted
that
rept
iles
will
be
sede
ntar
y an
d m
ove
slow
ly m
ost o
f the
tim
e,
perh
aps
patr
olli
ng a
t lo
w v
eloc
ity.
The
se a
ctiv
itie
s ar
e w
ithi
n th
eir
mea
gcr
aero
bic
supp
ort
capa
bili
ties
. T
he
deg
ree
to w
hich
rep
tile
s el
evat
e th
eir
met
abol
ism
and
the
clo
sene
ss o
f th
eir
appr
oach
to
aero
bic
lim
its
arc
of
cons
ider
able
in
tere
st
in
rela
ting
la
bora
tory
m
etab
olic
obs
erva
tion
s to
re
ptil
ian
ecol
ogic
al e
nerg
etic
s. L
ikew
ise
of in
tere
st is
the
exte
nt o
f ana
crob
ic
met
abol
ism
und
er n
atur
al f
ield
con
diti
ons.
Int
ense
act
ivity
can
bc
sup-
po
rted
onl
y an
aero
bica
lly
and
is r
equi
red
in p
reci
sely
thos
e in
stan
ces
\\ h
ich
are
of t
he g
reat
est
sign
ific
ance
to
surv
ival
and
rep
rodu
ctio
n (e
.g.
esca
pe,
purs
uit,
cou
rtsh
ip, t
erri
tori
al d
efen
se).
If t
he fu
ll an
aero
bic
capa
citj
is us
ed
only
onc
e a
wee
k or
eve
n on
ce a
yea
r, i
t is
like
ly t
o be
use
d un
der
criti
cal
circ
umst
ance
s. T
here
fore
, eve
n th
ough
it m
ay n
ot h
ave
a la
rge
quan
tita
tive
si
gnif
ican
ce i
n th
e ti
me
or e
nerg
y bu
dget
of
a re
ptil
e, t
he u
se o
f an
acro
bic
met
abol
ism
may
be
cruc
ial
to s
urvi
val.
Unf
ortu
nate
ly,
ther
e is
ver
y lit
tle
info
rmat
ion
avai
labl
e ab
out
the
exte
nt o
f ut
iliz
atio
n of
eit
her
aero
bic
or
anae
robi
c m
etab
olis
m i
n re
ptil
es n
atur
ally
act
ive
unde
r fie
ld c
ondi
tion
s.
Th
is w
ill d
oubt
less
ly b
e on
e of
the
mos
t ex
citi
ng a
nd p
rodu
ctiv
e ar
cas
of
futu
re r
esea
rch
in r
epti
lian
met
abol
ism
.
AL
BE
RT
F.
BE
NN
ET
T
Det
erm
inat
ion
of a
erob
ic m
etab
olic
exp
endi
ture
of
rept
iles
in
natu
ral
circ
umst
ance
s is
hig
hly
desi
rabl
e bu
t ve
ry d
iffi
cult
tech
nica
lly.
Dir
ect
mea
sure
men
t of g
as e
xcha
nge
in f
ield
-act
ive
anim
als
is g
ener
ally
impo
ssib
le.
How
ever
, a
nove
l st
udy
(Jac
kson
and
Pra
nge,
19
79)
dete
rmin
ed o
xyge
n co
nsum
ptio
n du
ring
egg
lay
ing
by s
ea t
urtl
es (
Che
loni
a m
ydas
). A
erob
ic
met
abol
ism
inc
reas
ed te
nfol
d ov
er r
esti
ng le
vels
, ind
icat
ing
both
con
side
r-
able
exe
rtio
n an
d en
ergy
exp
ense
. A
sim
ilar
met
abol
ic i
ncre
men
t w
as
mea
sure
d in
inc
ubat
ing
fem
ale
pyth
ons
unde
r ca
ptiv
e co
ndit
ions
(H
utch
i-
son
et a
/.,
1966
). T
he
time-
and-
estim
ated
-ene
rgy
budg
et a
ppro
ach
(e.g
. A
lexa
nder
an
d W
hitf
ord,
19
68;
Wils
on
and
Lee
, 19
74;
Ben
nett
an
d G
orm
an,
1979
) is u
sefu
l onl
y as
a ro
ugh
esti
mat
e of
indi
vidu
al o
r pop
ulat
ion
ener
gy f
low
. W
here
as t
hese
mea
sure
men
ts a
re p
roba
bly
accu
rate
for
the
pu
rpos
es i
nten
ded,
the
y ca
nnot
be
used
to
indi
cate
the
lev
el o
f ae
robi
c m
etab
olis
m i
n th
e fi
eld
as i
ts e
stim
ate
invo
lves
ori
gina
l as
sum
ptio
ns a
nd
esti
mat
es c
once
rnin
g th
ose
cost
s.
Inde
pend
ent
mea
sure
men
ts o
f fi
eld
met
abol
ism
are
nec
essa
ry t
o va
lidat
e th
e ap
proa
ch o
f tim
e-an
d-es
timat
ed-e
nerg
y bu
dget
s an
d to
pro
vide
an
accu
rate
ass
essm
ent o
f the
cos
ts o
f nat
ural
beh
avio
r. S
uch
mea
sure
men
ts a
re
feas
ible
uti
lizi
ng d
oubl
y-la
bele
d w
ater
(N
agy,
19
75,
volu
me
12). T
his
te
chni
que
has
been
util
ized
to
stud
y th
e m
etab
olic
rat
es o
f tw
o sp
ecie
s of
sc
elop
orin
e li
zard
s na
tura
lly
activ
e in
th
e fie
ld
(Sce
lopo
rus
occi
dent
alis
, B
enne
tt a
nd N
agy,
197
7; S
. jar
rot'i
, C
ongd
on e
t al
., 19
79).
Dur
ing
peri
ods
of t
he y
ear
whe
n th
e li
zard
s ar
e ac
tive
and
out
of t
heir
bur
row
s du
ring
the
da
y, t
he to
tal
met
abol
ic e
nerg
y ex
pend
ed i
s 2-
2.5
tim
es th
e in
tegr
ated
lev
el
of r
esti
ng m
etab
olis
m m
easu
red
on a
nor
mal
the
rmal
cyc
le. T
hat
is,
fie
ld
aero
bic
expe
ndit
ure
is o
nly
twic
e th
at m
easu
red
for
an i
nact
ive
anim
al
expo
sed
to t
he s
ame
ther
mal
reg
ime.
If
the
anim
als
are
assu
med
to
be
inac
tive
at
nigh
t, t
he in
crem
ent
asso
ciat
ed w
ith a
ctiv
ity d
urin
g th
e di
urna
l pe
riod
can
be
calc
ulat
ed (
Ben
nett
and
Nag
y, 1
977)
. Diu
rnal
met
abol
ic r
ate
in t
he f
ield
is
2.5-
3 ti
mes
res
ting
lev
el, o
r ab
out
one-
half
of
the
max
imum
le
vel
sust
aina
ble
aero
bica
lly (
max
imal
oxy
gen
cons
umpt
ion)
. T
he
aver
age
leve
l of
fiel
d m
etab
olis
m o
f Sce
lopo
rus i
s th
us w
ell w
ithi
n it
s ae
robi
c sc
ope
and
wel
l ab
ove
rest
ing
met
abol
ic l
evel
s. H
owev
er,
thes
e m
easu
rem
ents
in
tegr
ate
met
abol
ism
for
per
iods
of
days
or
wee
ks a
nd c
anno
t pr
ovid
e in
form
atio
n on
th
e va
riat
ion
in
met
abol
ic
rate
, th
at i
s,
how
of
ten
it
appr
oach
es m
axim
al o
r m
inim
al a
erob
ic l
imit
s.
Fiel
d en
erge
tics
may
als
o be
est
imat
ed b
y re
cord
ing
beha
vior
in th
e fi
eld
and
dupl
icat
ing
it w
hile
mea
suri
ng m
etab
olic
rat
e in
the
labo
rato
ry.
Th
is
appr
oach
was
und
erta
ken
to e
valu
ate
fora
ging
ene
rget
ics
of t
he l
izar
d C
nem
idop
horu
s mur
inus
(Ben
nett
and
Gle
eson
, 19
79; B
enne
tt a
nd G
orm
an,
3. T
HE
EN
ER
GE
T~
CS
OF
RE
PT
~L
MN
AC
T~
V~
TY
19
1
1979
). T
his
her
bivo
rous
liz
ard
spen
ds m
ost
of i
ts d
ay f
orag
ing
at a
bout
0.
13 k
m/h
, and
this
act
ivit
y ca
n be
und
erta
ken
on a
mot
or-d
rive
n tr
eadm
ill.
Met
abol
ic r
ate
at v
ario
us s
peed
s is s
how
n in
Fig
. 10
. Oxy
gen
cons
umpt
ion
at
norm
al f
orag
ing
spee
d, 0
.9 m
l Oz/
(g x
h),
is f
our
tim
es r
esti
ng le
vels
and
is
one-
half
m
axim
al
leve
ls.
Thu
s, n
orm
al
fora
ging
is
mai
ntai
ned
with
in
aero
bica
lly
supp
orta
ble
boun
dari
es
and
avoi
ds
anae
robi
c m
etab
olis
m.
How
ever
, m
axim
al s
usta
inab
le s
peed
is
only
0.3
km
/h a
nd e
xhau
stio
n oc
curs
rap
idly
at
0.5
km/h
, so
that
the
ran
ge o
f po
tent
ial
spee
ds is
nar
row
. A
n in
dica
tion
of
the
sign
ific
ance
of a
naer
obic
met
abol
ism
to a
ctiv
ity in
thi
s an
imal
is
give
n by
it
s bu
rst
spee
d, w
hich
ave
rage
s 8.
2 km
/h (
Ben
nett
, 19
80b)
. Thu
s, a
naer
obio
sis
expa
nds
the
acti
vity
cap
acit
y of
thi
s liz
ard
by
near
ly 3
0-fo
ld.
The
re a
re v
ery
few
stu
dies
of t
he e
xten
t of a
naer
obic
met
abol
ism
dur
ing
acti
vity
und
er f
ield
con
diti
ons.
A r
ecen
t la
bora
tory
stu
dy f
ound
sig
nifi
cant
la
ctic
aci
d ac
cum
ulat
ion
in g
arte
r sn
akes
(Tha
wm
ophi
s elr
gans
) dur
ing
atta
ck
and
capt
ure
of s
alam
ande
r pr
ey (
0.87
mg
lact
ate/
g m
ass
vers
us 0
.31
and
1.40
mg/
g fo
r re
stin
g an
d m
anua
lly
stim
ulat
ed s
nake
s re
spec
tivel
y; F
eder
an
d A
rnol
d, in
pre
ss).
Thu
s, a
naer
obio
sis
may
als
o be
use
d fo
r pr
ey c
aptu
re
by t
his
snak
e in
the
wil
d.
Ani
mal
s ca
n be
sur
veye
d in
fie
ld c
ondi
tion
s fo
r el
evat
ed b
ody
or b
lood
FIG
. 10. C
nem
idop
lror
rrs
tnrr
rrnr
rs. O
xypc
n co
nsum
ptio
n as
a fu
ncti
on o
f spc
cd a
t 40
C w
hilc
wal
hinp
on
a m
otor
-dri
ven
trca
dmill
. Rcd
raw
n fr
om I
3cnn
ctt
and
Cilc
cson
(19
79).
2.0
1.5
- - I r
- I 0
0" I
.0-
-
E - .g 0.5
-
Cne
rnid
opho
rus
rnur
inus
A
A
A
A
A
A
- A A
A
A
A
A
A
A
A A
-A
A A
A A
01
I
I I
1 0
0.1
0
2
0 3
0
4
km
/h
192
AL
BE
RT
F.
BE
NN
ET
T
lact
ate
conc
entr
atio
ns.
Ele
vate
d le
vels
wou
ld
indi
cate
rec
ent
anae
robi
c ac
tivi
ty.
Blo
od l
acta
te l
evel
s in
a g
roup
of
bask
ing
and
beac
hing
mar
ine
igua
nas
(Am
blyr
hync
hus
cris
tatu
s) w
ere
indi
stin
guis
habl
e fr
om t
hose
of
anim
als
rest
ing
quie
tly
in t
he la
bora
tory
. Con
sequ
entl
y, r
outi
ne a
ctiv
ity
in
this
liz
ard,
eve
n du
ring
div
ing,
doe
s no
t ap
pear
to
util
ize
anae
robi
osis
. H
owev
er,
both
bur
st s
wim
min
g an
d ru
nnin
g be
havi
or r
esul
t in
ext
ensi
ve
anae
robi
c m
etab
olis
m (
Bar
thol
omew
et
al.,
1976
; Gle
eson
, 19
80a)
. Blo
od
lact
ate
leve
ls i
ncre
ase
sign
ific
antl
y du
ring
egg
-lay
ing
beha
vior
by
the
sea
turt
le,
Che
loni
a m
ydas
(Ja
ckso
n an
d P
rang
e,
1979
). W
hole
bod
y la
ctat
e co
ncen
trat
ions
wer
e m
easu
red
in a
ser
ies
of A
nolis
bon
aire
nsis
, res
ting
in th
e la
bora
tory
and
sam
pled
fro
m t
he f
ield
thr
ough
out
the
day
(Ben
nett
et
al.,
1981
). M
ean
leve
ls o
f la
ctat
e in
fie
ld a
ctiv
e li
zard
s ge
nera
lly
exce
ed r
esti
ng
leve
ls a
nd s
ome
indi
vida
l an
imal
s ha
d la
ctat
e co
ncen
trat
ions
exc
eedi
ng
1.0
mg/
g. M
ale
liza
rds
prov
oked
int
o te
rrit
oria
l de
fens
e by
the
intr
oduc
tion
of
ano
ther
mal
e ha
ve e
leva
ted
lact
ate
leve
ls in
pro
port
ion
to th
e m
agni
tude
of
the
ir b
ehav
iora
l re
spon
se.
Ana
erob
iosi
s ap
pear
s to
be
ra
rely
us
ed
whe
n re
ptil
es
dive
fr
eely
. A
naer
obic
cap
acit
ies
are
wel
l de
velo
ped
and
lact
ic a
cid
prod
ucti
on i
s gr
eat
duri
ng
forc
ed
dive
s (A
llig
ator
, A
nder
sen,
19
61;
Am
blyu
hj~n
chus
, Bar
- th
olom
ew e
t al
., 19
76; C
helo
nia,
Ber
kson
, 19
66; H
ocha
chka
et
al.,
1975
; L
a.pe
mis
, Sey
mou
r an
d W
ebst
er,
1975
; Neu
odia
, M
urda
ugh
and
Jack
son,
19
62; P
seud
emys
, Rob
in e
t al.,
196
4; A
ltm
an a
nd R
obin
, 19
69, P
enny
, 19
74).
H
owev
er, o
nly
exce
ptio
nall
y do
free
ly d
ivin
g an
imal
s sh
ow e
leva
ted
lact
ate
leve
ls (
Hea
twol
e, 1
978;
Am
blyr
hync
hus,
Gle
eson
, 19
80a;
Lap
emis
, Sey
mou
r an
d W
ebst
er,
1975
; Lat
icau
da, S
eym
our,
197
9, th
is v
olum
e; V
aran
us, W
ood
and
Joha
nsen
, 19
74).
Th
e pr
onou
nced
ana
erob
ic r
espo
nse
seen
in
forc
ed
dive
s m
ay b
e du
e to
act
ivit
y, s
tres
s, a
nd/o
r ps
ycho
logi
cal
fact
ors.
Ana
erob
ic
met
abol
ism
in
di
ving
re
ptil
es
appe
ars
to b
e re
serv
ed
for
exce
ptio
nal
circ
umst
ance
s, a
s w
hen
prol
onge
d di
ves
or r
apid
esc
ape
beha
vior
und
er-
wat
er a
re r
equi
red.
VI.
Con
clu
sion
s an
d F
utur
e D
irec
tion
s
Th
e da
ta s
umm
ariz
ed i
n th
is c
hapt
er p
erm
it u
s to
infe
r so
me
broa
d, i
f te
ntat
ive,
gen
eral
izat
ions
con
cern
ing
patt
erns
of
rept
ilia
n ac
tivi
ty e
ner-
ge
tics.
Max
imal
leve
ls o
f oxy
gen
cons
umpt
ion
are
appr
oxim
atel
y 6
10
tim
es
rest
ing
leve
ls. B
oth
max
imal
and
res
ting
rat
es a
re f
airl
y ty
pica
l of
thos
e of
ot
her
ecto
ther
mic
ver
tebr
ates
and
are
low
in
com
pari
son
to th
ose
of b
irds
an
d m
amm
als.
The
y ar
e ab
solu
tely
low
in
the
leve
l of e
xert
ion
whi
ch t
hey
perm
it. C
apac
itie
s of r
epti
les
to s
uppo
rt b
ehav
ior
aero
bica
lly
are
lim
ited
and
th
eir
max
imal
aer
obic
spe
eds
are
only
abo
ut 1
.0 k
m/h
at b
est.
Th
e th
erm
al
3. T
HE
EN
ER
GE
T~
CS
OF
RE
PT
~L
~A
N
AC
TIV
~T
Y
193
depe
nden
ce o
f ox
ygen
util
izat
ion
grea
tly
decr
ease
s th
is a
lrea
dy l
imite
d ae
robi
c ab
ilit
y at
low
bod
y te
mpe
ratu
re.
Sup
plem
enta
tion
of
aero
bic
with
ana
erob
ic m
etab
olis
m g
reat
ly e
xpan
ds
the
met
abol
ic
pow
er
whi
ch
rept
iles
m
ay
use
for
activ
ity.
Ana
erob
ic
ener
geti
cs a
re o
f hi
gh
inte
nsit
y w
ith a
gre
ater
tim
e-de
pend
ent
ener
gy
gene
rati
on c
apac
ity
than
tho
se o
f ae
robi
osis
. T
he
rela
tive
inse
nsiti
vity
of
anae
robi
osis
to
chan
ges
in b
ody
tem
pera
ture
allo
ws
burs
t ac
tivity
ove
r a
broa
d th
erm
al r
ange
. H
owev
er,
exte
nsiv
e an
aero
bic
met
abol
ism
ent
ails
es
haus
tion
and
dis
rupt
ion
of n
orm
al p
hysi
olog
ical
fun
ctio
n an
d is
eff
ectiv
e ov
er a
ver
y sh
ort
time.
T
he
cont
rast
bet
wee
n th
e ae
robi
c an
d an
aero
bic
abili
ties
of r
eptil
es
impr
oves
ou
r un
ders
tand
ing
of
patt
erns
of
re
ptili
an
beha
vior
. T
he
detr
imen
tal
effe
cts
of a
naer
obio
sis
mak
e lo
w-i
nten
sity
ac
tivity
ad
van-
ta
geou
s. I
t is
our
im
pres
sion
tha
t re
ptil
es s
pend
muc
h of
the
ir t
ime,
wen
w
hen
"act
ive"
in
the
fiel
d, r
emai
ning
qui
esce
nt f
or lo
ng p
erio
ds o
r m
akin
g on
ly
slow
an
d de
libe
rate
m
ovem
ents
. T
hese
are
sup
port
able
thr
ough
ae
robi
c m
etab
olis
m.
Th
is r
elat
ive
inac
tivity
is
punc
tuat
ed b
y ra
pid
and
espl
osiv
e bu
rsts
, fu
eled
by
anae
robi
c m
etab
olis
m.
Th
e co
ntra
st b
etne
en
sede
ntar
y, s
omet
imes
im
mob
ile
beha
vior
and
int
ense
and
rap
id a
ctiv
ity,
whi
ch m
akes
rep
tile
s su
ch f
asci
natin
g an
imal
s to
wat
ch,
find
s its
bas
is i
n di
ffer
entia
l m
etab
olic
sup
port
for
the
se b
ehav
iora
l m
odes
. O
ur u
nder
stan
ding
of t
he li
mit
s and
con
sequ
ence
s of
rept
ilia
n ac
tivity
has
m
oved
far
wit
hin
the
past
dec
ade.
A f
urth
er e
xpan
sion
of
our
know
ledg
e is
to
be
an
tici
pate
d in
th
e ne
ar
futu
re.
Onl
y ge
nera
l lim
its
of
aero
bic
met
abol
ism
(m
easu
rem
ents
of
rest
ing
and
max
imal
oxy
gen
cons
umpt
ion)
no
w h
ave
a sa
tisf
acto
ry d
ata
base
. How
ever
, eve
n fo
r th
ese
we
need
a m
uch
grea
ter
taxo
nom
ic b
read
th o
f obs
erva
tion
to p
erm
it c
orre
latio
n of
met
abol
ic
Icve
l w
ith b
ehav
iora
l ty
pe o
r ec
olog
ical
cir
cum
stan
ce.
Our
kno
wle
dge
is
inco
mpl
ete
in n
earl
y al
l ot
her
area
s of
phy
siol
ogy,
beh
avio
r, a
nd e
colo
gy
rela
ting
to r
epti
lian
act
ivity
. In
num
erou
s pl
aces
thr
ough
out
the
chap
ter,
I
have
ind
icat
ed
spec
ific
are
as f
or w
hich
dat
a ar
e pa
rtic
ular
ly s
cant
y or
cx
tcns
ions
of n
ew in
form
atio
n ar
e re
quir
ed. I
t wou
ld b
e us
eful
to h
ave
mor
e de
tail
ed i
nfor
mat
ion
on n
earl
y an
y of
thes
e ar
eas.
A
ltho
ugh
it is
som
ewha
t ri
sky
to s
ugge
st d
esir
ed d
irec
tion
s fo
r re
sear
ch,
the
follo
win
g ar
e pr
obab
le t
hem
es w
hich
will
car
ry t
his
area
of
rese
arch
fo
rwar
d in
the
futu
re.
A p
ersi
sten
t th
eme
in r
epti
lian
bio
logy
has
bee
n th
e in
flue
nce o
f bo
dy t
empe
ratu
re. P
resu
mab
ly, t
his
will
con
tinu
e to
be
a to
pic
of c
onsi
dera
ble
inte
rest
and
the
oret
ical
im
port
ance
. Alth
ough
the
the
rmal
de
pend
ence
of
aero
bic
capa
citie
s ar
e fa
irly
wel
l de
term
ined
, dat
a ar
e on
ly
frag
men
tary
for
man
y of
the
var
iabl
es d
iscu
ssed
her
e, i
nclu
ding
ana
erob
ic
scop
e, t
otal
met
abol
ic i
nput
to
activ
ity,
cost
of
loco
mot
ion
and
nias
imal
ae
robi
c sp
eed,
and
beh
avio
ral
capa
citie
s. A
ll th
ese
area
s re
quir
e fu
rthe
r
194
AL
BE
RT
F.
BE
NN
ET
T
exam
inat
ion
of t
he in
flue
nce
of b
ody
tem
pera
ture
bef
ore
we
can
gene
raliz
e ef
fect
ivel
y co
ncer
ning
rep
tilia
n ca
pabi
litie
s. I
n an
othe
r vei
n, t
he p
hysi
olog
i-
cal
base
s of
the
se p
erfo
rman
ce c
hara
cter
isti
cs a
re s
till
larg
ely
unin
vest
i-
gate
d. W
e la
ck m
echa
nist
ic e
xpla
nati
ons
for s
uch
phen
omen
a as
the
ther
mal
in
depe
nden
ce o
f ana
erob
iosi
s an
d th
e lo
w le
vel o
f oxy
gen-
proc
essi
ng a
bilit
y of
rep
tile
s. T
hese
are
are
as in
whi
ch c
ompa
rati
ve p
hysi
olog
ists
spe
cial
izin
g in
res
pira
tory
, ci
rcul
ator
y, a
nd m
uscu
lar
phys
iolo
gy c
ould
mak
e su
bsta
ntia
l co
ntri
buti
ons.
Ano
ther
are
a of
inte
rest
is th
e si
gnif
ican
ce to
rept
ilian
act
ivity
of
oth
er a
naer
obic
ally
for
med
end
-pro
duct
s be
side
s la
ctic
aci
d, e
spec
ially
th
e co
ntri
buti
on o
f A
TP
and
cre
atin
e ph
osph
ate
depl
etio
n. S
tudi
es o
f lo
com
otio
n, i
n ad
diti
on t
o ex
amin
ing
aero
bic
lim
its
and
ther
mal
dep
en-
denc
e, s
houl
d al
so c
once
ntra
te o
n th
e en
erge
tic
impl
icat
ions
of
vari
ous
loco
mot
ory
mod
ific
atio
ns a
nd m
odes
, in
clud
ing
swim
min
g, l
imbl
essn
ess,
an
d bi
peda
lity
. A
t pr
esen
t, w
e kn
ow v
ery
litt
le a
bout
the
phy
siol
ogy
and
beha
vior
al c
onse
quen
ces
of re
cove
ry a
fter
act
ivit
y in
rep
tile
s. T
his
is a
n ar
ea
in w
hich
sub
stan
tial
wor
k co
uld
proc
eed
rapi
dly.
Mos
t si
gnif
ican
tly,
we
need
fur
ther
mea
sure
men
ts o
f en
erge
tics
und
er n
atur
al o
r se
mi-
natu
ral
cond
itio
ns.
The
se s
houl
d le
t us
det
erm
ine
the
exte
nt t
o w
hich
rep
tilia
n be
havi
or
norm
ally
ap
proa
ches
it
s m
etab
olic
li
mit
s an
d th
e ex
tent
of
anae
robi
c m
etab
olis
m u
nder
fie
ld c
ondi
tion
s.
Th
ere
is s
till m
uch
info
rmat
ion
need
ed,
alth
ough
our
und
erst
andi
ng h
as
incr
ease
d su
bsta
ntia
lly
in a
ver
y sh
ort t
ime.
It
is s
omew
hat d
isco
urag
ing
to
real
ize
that
fo
r m
any
of
the
vari
able
s co
nsid
ered
, re
ptil
es
are
the
best
-stu
died
gro
up o
f ani
mal
s. W
e re
quir
e m
uch
mor
e co
mpa
rati
ve d
ata
for
othe
r ve
rteb
rate
gr
oups
be
fore
w
e ca
n su
cces
sful
ly
unde
rsta
nd
the
oppo
rtun
itie
s of
and
lim
itat
ions
on
beha
vior
and
act
ivity
pro
vide
d by
the
ve
rteb
rate
pla
n of
org
aniz
atio
n.
Ack
no
wle
dg
men
ts
Fina
ncia
l su
ppor
t was
pro
vide
d by
Nat
iona
l Sci
ence
Fou
ndat
ion
Gra
nts
PCM
77-
2420
8 an
d 81
-023
31,
and
Nat
iona
l In
stit
utes
of
Hea
lth
Gra
nt 5
K
O4
AM
0003
5 1.
Ref
eren
ces
Ale
xand
er, C
. E. a
nd W
hitf
ord,
W.
G. (
1968
). E
nerg
y re
quir
emen
ts o
f U
ta st
ansb
urin
na.
Cup
cia
1968
, 678
-683
. A
ltman
, M. a
nd R
obin
, E. D
. (19
69).
Surv
ival
dur
ing
prol
onge
d an
aero
bios
isas
a fu
nctio
n of
an
unu
sual
ada
ptat
ion
invo
lvin
g la
ctat
e de
hydr
ogen
ase s
ubun
its. C
ornp
. Bio
cher
n. P
hj&
d.
30.
1 179
- 1 1
87.
~n
dir
sen
, H.
T.
(196
1).
Phys
iolo
gica
l adj
ustm
ents
to
prol
onge
d di
ving
in
the
Am
eric
an
allig
ator
All
iga~
ur rn
~ssi
ssip
picn
sis.
Ac
~a
phys
iol.
scan
d. 5
3, 2
34
5.
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
19
.5
Asp
lund
, K
. K
. (1
970)
. M
etab
olic
sc
ope
and
body
tc
mpc
ratu
rcs
of
whi
ptai
l liz
ards
(C
nem
idop
horu
s).
Her
pero
logi
ca 2
6, 4
03
4 1 1
. R
akke
r, R
. T. (
1972
). L
ocom
otor
ene
rget
ics o
f liz
ards
and
mam
mal
s co
mpa
red.
PIy
siuI
~~
irr
15. 7
6.
Rar
thol
omew
, G
. A
. an
d T
ucke
r, V
. A
. (1
963)
. C
ontr
ol o
f ch
ange
s in
bod
y tc
mpc
ratu
re.
mct
abol
ism
, an
d ci
rcul
atio
n by
the
aga
mid
liz
ard,
Arn
phib
olur
rts b
arbn
~rcs
. Ph.
)~io
l. Zed
. 36
, 19
9-21
8.
Bar
thol
omew
, G
. A
. an
d T
ucke
r,
V.
A.
(196
4).
Size
, bo
dy
tcm
pera
turc
, th
erm
al
cond
ucta
nce,
oxy
gen
cons
umpt
ion,
and
hea
rt r
ate
in A
ustr
alia
n va
rani
d liz
ards
. P/
g,sr
ol.
Zoiil
. 37,
341
-354
. B
arth
olom
ew, G
. A. a
nd V
leck
, D. (
1979
). T
he
rela
tion
of o
xygc
n co
nsum
ptio
n to
bod
y si
ze
and
to h
eati
ng a
nd c
oolin
g in
the
Gal
apag
os m
arin
e ig
uana
, A
m6!
yrh~
~nrl
rns rr
isrn
trts
. 3.
rom
p. P
hjls
iol.
132,
285
-288
. B
arth
olom
ew,
G. A
,, T
ucke
r, V
. A. a
nd L
ee,
A.
K. (
1965
). O
xygc
n co
nsum
ptio
n, t
hcnn
al
cond
ucta
nce,
and
hea
rt r
ate
in t
he A
ustr
alia
n sk
ink
T~l
rqua
scin
roid
cs.
Gpc
iu
1965
, 16
9- 1
73.
13ar
thol
omew
, G
. A
., B
enne
tt,
A.
F. a
nd D
awso
n, W
. R
. (1
976)
. Sw
imm
ing,
div
ing,
and
la
ctat
e pr
oduc
tion
of t
he m
arin
c ig
uana
, Am
b~rh
jtnc
hus cr
is/a
/us.
Cop
fin
1976
, 700
- 720
. I3
encd
ict,
F.
G.
(193
2).
"The
Ph
ysio
logy
of
Lar
ge R
epti
les.
" Pu
bl.
Car
ncfi
ie I
mtir
. l~
l'ash
ingf
on (4
25),
1-53
9.
Ilcn
nctt
, A
. F. (
1972
). T
he
effe
ct o
f act
ivity
an
oxyg
en c
onsu
mpt
ion,
oxy
gn d
ebt,
and
hca
rr
rate
in t
he li
zard
s V
arat
rrts
ptcl
dii a
nd S
auro
mak
s hi
spid
us. 3
. cnm
p. I'
h.)a
iol.
79,2
59-
280.
Il
cnnc
tt,
A. F
. (19
73).
Blo
od p
hysi
olog
y an
d ox
ygen
tra
nspo
rt d
urin
g ac
tivity
in
two
lizar
ds,
Var
nnus
gou
ldii
and
Saur
omal
us h
ispi
dus.
Com
p. B
ioch
~m. P
h~~
sinl
. 46A
, 673
-690
. Ij
cnnc
tt,
A. F
. (19
78).
Act
ivity
met
abol
ism
of
the
low
er v
erte
brat
es. A
nn.
Rev
. Ph
)~d
. 10.
4474
69.
Ilcn
nett
, A
. F
. (1
980a
). T
he
met
abol
ic f
ound
atio
ns o
f ve
rteb
ratc
beh
avio
r. R
iosr
icnr
c~ 30
, 45
2-45
6.
Ilcn
nctt
, A
. F
. (1
980b
). T
he t
herm
al d
epen
denc
e of
liz
ard
beha
viou
r. A
nirn
. Il
char
. 28
. 75
2-76
2.
l3cn
nett,
A.
F. (
1982
). E
colo
gica
l co
nseq
uenc
es o
f th
e ac
tivity
met
abol
ism
of
liznr
ds.
In
"Liz
ard
Eco
logy
: St
udie
s on
a M
odel
Org
anis
m."
(R
. Il
ucy,
T.
Scho
cncr
, and
I.
K.
Pian
ka,
eds)
. H
arva
rd U
nive
rsit
y Pr
ess,
Cam
brid
ge.
In p
rcss
. Il
cnnc
tt,
A.
F.
and
Dal
zcll,
B.
(197
3).
Din
osau
r ph
ysio
logy
: A
cri
tiqu
e. E
rolr
rtio
~ 27.
17
0- 1
74.
13cn
nctt,
A. F
. and
Daw
son,
W. R
. (19
72).
Aer
obic
and
ana
erob
ic m
etab
olis
m d
urin
g ac
tivity
in
thc
liza
rd D
ipso
saw
us d
orsa
lis. 3
. cm
p. 1
'11,~
~sio
l. 81,
289%
299.
Ih
nc
tt,
A.
F. a
nd D
awso
n, W
. R
. (1
976)
. Met
abol
isni
. In
"B
iolo
gy o
f th
c R
cptil
in."
((1.
G
ans
and
W.
R. D
awso
n, c
ds).
Aca
dem
ic P
ress
, L
ondo
n, 5
(3),
127
-223
. Il
cnnc
tt,
A.
F.
and
Gle
eson
, T
. T
. (1
976)
. A
ctiv
ity m
ctab
olis
m i
n th
c liz
ard
Scrl
opor
ris
occi
denf
alis
. Phy
siol
. Z
oiil.
49,
65-
76.
Ijcn
nctt
, A. 1
7. a
nd G
lees
on, T
. T. (
1979
). h
ktab
olic
exp
cndi
turc
and
the
cos
t of f
orag
ing
in
the
lizar
d C
ncm
idop
horu
s m
urin
us.
Cop
eia
1979
, 573
-577
. Il
cnnc
tt,
A. I
:. an
d G
orm
an, G
. C. (
1979
). P
opul
atio
n de
nsit
y an
d en
crgc
tics
of li
zard
s on
i~
trop
ical
isl
and.
Oec
olog
in 4
2, 3
39-3
58.
llcn
nctt
, A. 1
:. an
d L
icht
, P. (
1972
). A
naer
obic
met
abol
ism
dur
ing
acti
\-it
y in
lizar
ds.3
. cco
mp.
1'h)
~sio
l. 81
, 27
7-28
8.
Ilcn
nctt
, A
. F. a
nd L
icht
, P.
(19
73).
Kcl
ativ
c co
ntri
buti
ons o
fana
crob
ic a
nd a
erob
ic c
ncrg
y pr
oduc
tion
dur
ing
activ
ity i
n A
mph
ibin
. 3. c
com
p. Ph
ysio
l. 87
. 35
1-36
0.
kn
nct
t, A
. F
. and
Lic
ht,
P. (
1974
). A
naer
obic
mct
abol
ism
dur
ing
activ
it:
in a
mph
ihia
ns.
Con
rp.
Bio
chem
. Phy
siol
. 48
A,
3 19
-327
.
196
AL
BE
RT
F.
BE
NN
ET
T
Ben
nett
, A. F
. and
Nag
y, K
. A. (
1977
). E
nerg
y ex
pend
itur
e in
free
-ran
ging
liz
ards
. Eco
logy
58
, 697
-700
. en
n nett
, A. F
. and
Rub
en, J
. (19
75).
Hig
h al
titu
de a
dapt
atio
n an
d an
aero
bios
is in
sce
lopo
rine
liz
ards
. C
omp.
Bio
chem
. Ph,
ysio
l. 50
A,
105-
108.
B
enne
tt,
A.
F. a
nd R
uben
, J.
A.
(197
9). E
ndot
herm
y an
d ac
tivity
in
vert
ebra
tes.
Sci
ence
, N
. Y. 2
06,
649-
654.
B
enne
tt,
A.
F. a
nd W
ake,
M.
(197
4).
Met
abol
ic c
orre
late
s of
act
ivity
in
the
caec
ilian
G
eorr
yper
es se
raph
inii.
Cop
eia
1974
, 764
-769
. B
enne
tt,
A.
F.,
Daw
son,
W.
R.
and
Bar
thol
omew
, G
. A
. (1
975)
. E
ffec
ts o
f ac
tivity
and
te
mpe
ratu
re o
n ae
robi
c an
d an
aero
bic
met
abol
ism
in
the
Gal
apag
os m
arin
e ig
uana
. 3.
com
p. P
h,)a
iol.
100,
3 17
-329
. B
enne
tt, A
. F.,
Gle
eson
, T. T
. and
Gor
man
, G. C
. (19
81).
Ana
erob
ic m
etab
olis
m in
a li
zard
(A
nolis
bon
aire
nsis
) un
der
natu
ral
cond
itio
ns. P
hyio
l. Z
ool.
54, 2
37-2
41.
Ber
ger,
M.,
Har
t, J
. S. a
nd R
oy, 0
. Z. (
1970
). R
espi
ratio
n, o
xyge
n co
nsum
ptio
n an
d he
art
rate
in
som
e bi
rds
duri
ng r
est
and
flig
ht.
Z.
cerg
l. Ph
ysio
l. 66
, 201
-214
. B
erks
on, H
. (19
66).
Phys
iolo
gica
l adj
ustm
ents
to p
rolo
nged
div
ing
in th
e Pa
cifi
c gr
een
turt
le
(Che
loni
a m
ydas
aga
ssiz
il).
Com
p. B
ioch
em. P
hysi
ol.
18,
101-
1 19
. B
rett
, J.
R.
(196
4).
Th
e re
spir
ator
y m
etab
olis
m a
nd s
wim
min
g pe
rfor
man
ce o
f yo
ung
sock
eye
salm
on.3
. Fi
sh.
Res
. B
d. C
an.
21,
1183
-122
6.
Cho
drow
, R
. E
. and
Tay
lor,
C. R
. (19
73).
Ene
rget
ic c
ost o
f lim
bles
s lo
com
otio
n in
sna
kes.
Fe
dn. P
roc.
Fed
n. A
m.
Sacs
. exp
. Bio
l. 32
, 422
. C
ongd
on, J
. D.,
Bal
linge
r, R
. E. a
nd N
agy,
K. A
. (19
79).
Ene
rget
ics,
tem
pera
ture
and
wat
er
rela
tions
in
win
ter
aggr
egat
ed S
celo
poru
s jar
rovi
(Sa
uria
: Igu
anid
ae).
Eco
logy
60,
30-
35.
Cou
lson
, R
. A
. (19
79).
Ana
erob
ic g
lyco
lysi
s: T
he
Smit
h an
d W
esso
n of
the
hete
roth
erm
s.
Pers
p. B
iol.
Med
. 22,
465
-479
. C
ouls
on,
R.
A.
(198
0).
Rat
e cu
rves
for
gly
coly
sis
and
for
glyc
ogen
res
ynth
esis
in
a liz
ard.
C
omp.
Bio
chem
. Phj
xiol
. 66
B,
67-7
3.
Cou
lson
, R
. A
. an
d H
erna
ndez
, T
. (1
964)
. "B
ioch
emis
try
of t
he A
lliga
tor:
A S
tudy
of
Met
abol
ism
in
Slow
Mot
ion.
" L
ouis
iana
Sta
te U
nive
rsit
y Pr
ess,
Bat
on R
ouge
. C
ragg
, P.
-4.
(197
8).
Oxy
gen
cons
umpt
ion
in t
he l
izar
d ge
nus
Lac
erta
in
rela
tion
to d
ie1
vari
atio
n, m
axim
um a
ctiv
ity a
nd b
ody
wei
ght. 3.
exp.
Bio
l. 77
, 33-
56.
Daw
son,
W.
R.
(196
7).
Inte
rspe
cifi
c va
riat
ion
in p
hysi
olog
ical
re
spon
ses
of l
izar
ds t
o te
mpe
ratu
re.
In "
Liz
ard
Eco
logy
: A
Sym
posi
um."
(W
. W
. M
ilst
ead,
ed.
). U
niv.
of
Mis
sour
i Pr
ess,
Col
umbi
a, p
p. 2
30-2
57.
Daw
son,
W. R
. (19
75).
On
the
phys
iolo
gica
l sig
nifi
canc
e of
the
pref
erre
d bo
dy te
mpe
ratu
res
of r
eptil
es.
In "
Pers
pect
ives
in
Bio
phys
ical
Eco
logy
." (
D.
h4. G
ates
and
R.
B. S
chm
erl,
eds)
. Sp
ring
er V
erla
g, N
ew Y
ork,
pp.
443
473.
D
mi'e
l, R
. (19
72).
Eff
ect o
f act
ivity
and
tem
pera
ture
on
met
abol
ism
and
wat
er lo
ss in
snak
es.
Am
. 3. P
hj~s
iol. 2
23,
510-
5 16
. D
mi'e
l, R
. and
Bor
ut,
A. (
1972
). T
herm
al b
ehav
ior,
hea
t exc
hang
e, a
nd m
etab
olis
m i
n th
e de
sert
sna
ke S
pale
roso
phis
clrf
ford
i. Ph
ysio
l. Z
ool.
45, 7
8-94
. D
mi'e
l, R
. and
Rap
pepo
rt, D
. (19
76).
Eff
ect o
ftem
pera
ture
on
met
abol
ism
dur
ing
runn
ing
in
the
lizar
d U
rom
asri
x ae
gypr
ius.
Php
iol.
Zoo
l. 49
, 77
-84.
D
uvde
vani
, I. a
nd B
orut
, A. (
1974
). O
xyge
n co
nsum
ptio
n an
d ev
apor
ativ
e w
ater
loss
in f
our
spec
ies
of A
canr
hoda
c(y1
us (
Lac
teri
dae)
. Cop
eia
1974
, 155
-164
. E
kblo
m,
B. (
1969
). E
ffec
t of P
hysi
cal T
rain
ing
on O
xyge
n T
rans
port
Sys
tem
s in
Man
. Acr
a ph
jlsio
l. sc
and.
Sup
pl. 3
28.
Fede
r, h
l. E
. an
d A
rnol
d, S
. J.
(in
pres
s).
Ana
erob
ic m
etab
olis
m a
nd b
ehav
ior
duri
ng
pred
ator
y en
coun
ters
bet
wee
n sn
akes
(T
ham
noph
is e
lega
ns)
and
sala
man
ders
(Ple
rhod
on
jord
ani)
. O
ecol
ogia
(Ber
l.)
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TIL
IAN
AC
TIV
ITY
19
7
Fry,
F. E
. J. (
1947
). E
ffec
ts o
n th
e E
nvir
onm
ent o
n A
nim
al A
ctiv
ity. P
ub. O
nr. F
ish.
Res
. Lab
. (6
8).
1-62
. G
atte
n, R
. E
. Jr
. (1
974)
. E
ffec
ts o
f te
mpe
ratu
re a
nd a
ctiv
ity o
n ae
robi
c an
d an
aero
bic
met
abol
ism
and
hea
rt r
ate
in t
he tu
rtle
s P
seud
em~~
s scri
pla
and
Terr
apen
e or
nara
. Com
p.
Bio
chem
. Ph
ysio
l. 48
A, 6
19-6
48.
Gat
ten,
R. E
. Jr.
(197
5). E
ffec
ts o
f act
ivity
on
bloo
d ox
ygen
sat
urat
ion,
lact
ate,
and
pl I
in th
e tu
rtle
s Ps
eude
mys
scr
ipfa
and
Terr
apen
e or
rrat
a. P
hj~s
iol. Z
ool.
48,
24-3
5 G
atte
n, R
. E. J
r. (
1978
). A
erob
ic m
etab
olis
m i
n sn
appi
ng tu
rtle
s, C
hely
dra
serp
enlin
a, a
ftcr
th
erm
al a
cclim
atio
n. C
omp.
Bio
chem
. Phj
~sio
l. 61A
, 325
-337
. G
lees
on, T
. T. (
1979
a). T
he
effe
cts
of tr
aini
ng a
nd c
aptiv
ity o
n th
e m
etab
olic
capa
city
of t
hc
lizar
d Sc
elop
orus
occ
iden
falis
. 3. c
omp.
Pkj
uiol
. 12
9, 1
23-1
28.
G
lees
on,
T.
T.
(197
9b).
For
agin
g an
d tr
ansp
ort
cost
s in
the
Gal
apag
os m
arin
c ig
uana
, A
mbl
yrhy
nchu
s cr
isfa
tus.
Phy
siol
. Zoo
l. 52
, 51
9-55
7.
Gle
eson
, T. T
. (19
80a)
. Lac
tic
acid
pro
duct
ion
duri
ng fi
eld
activ
ity in
the
Gal
apag
os m
arin
c ig
uana
, Am
blyr
hjln
chus
cri
sfar
us. P
hysi
ol. Z
ool.
53,
1.57
-162
. G
lces
on, T
. T. (
1980
b). M
etab
olic
rec
over
y fr
om e
xhau
stiv
e ac
tivity
by
a la
rgc
liznr
d.3.
t~pp
. Ph
ysio
l., R
espi
r.,
Eno
iron
. Exe
r. P
h,ys
iol.
48,
689-
694.
G
lecs
on,
T.
T.,
Mit
chel
l, G
. S
. an
d B
enne
tt,
A.
F.
(198
0). C
ardi
ovas
cula
r rc
spon
scs
to
grad
ed a
ctiv
ity in
the
liza
rds
Var
anus
and
Igu
ana.
Am
. 3. P
hysi
ol. 2
39 (
Rg
. Irr
reg.
Com
p.
Phys
iol. 8), R
174-
R 17
9.
Gol
ley,
F. B
. (19
68).
Sec
onda
ry p
rodu
ctiv
ity in
terr
estr
ial c
omm
uniti
es. A
m. Z
nnl.
8,53
-59.
G
ratz
, R. K
. and
Hut
chis
on, V
. H. (
1977
). E
nerg
etic
s fo
r act
ivity
in th
e di
amon
dbac
k w
atcr
sn
ake,
Nat
rix
rhom
bife
ra P
hysi
ol. Z
ool.
50, 9
9-1
14.
Gre
enw
ald,
0.
E.
(197
1). T
he e
ffec
t of
bod
y te
mpe
ratu
re o
n ox
ygen
con
sum
ptio
n an
d he
art
rate
in t
he S
onor
a go
pher
sna
ke,
Pifu
ophi
s caf
enrf
er a
fini
s H
allo
wel
l. C
opei
a 19
71,
98-1
06.
Gre
enw
ald,
0.
E.
(197
4).
The
rmal
dep
ende
nce
of s
trik
ing
and
prey
cap
tilrc
by
goph
er
snak
es.
Cop
eia
1974
, 14
1-11
8.
Hea
twol
e, H
. (1
978)
. Ada
ptat
ions
of
mar
ine
snak
es. A
m. S
ci. 6
6, 5
94-6
04.
Hem
min
gsen
, A
. M
. (1
960)
. Ene
rgy
Met
abol
ism
as
Rel
ated
to
Bod
y Si
ze a
nd R
espi
rato
ry
Surf
aces
, an
d It
s E
volu
tion.
Rep
. Ste
no. M
em.
Hos
p. N
ord.
Ins
ulin
lab.
9,
110
pp.
Hil
lman
, S.
S.,
Shoe
mak
er, V
. H., P
utna
m,
R. a
nd W
ithe
rs, P
. C. (
1979
). K
eass
cssm
cnt o
f ~
cro
bic
met
abol
ism
in
amph
ibia
ns d
urin
g ac
tivi
ty.3
. co
mp.
Ph,
~~si
ol.
129,
309
-313
. H
ocha
chka
, P.
W.,
Ow
en,
T.
G.,
Alle
n, J
. F
. an
d W
hitto
w,
G.
C.
(197
5). h
lult
iple
end
pr
oduc
ts o
f an
aero
bios
is i
n di
ving
ver
tebr
ates
. C
omp.
Rio
chem
. Phj
~sio
l. 50B,
17--
22.
Hof
fman
, M. (
1973
). "L
ocom
otor
Act
ivity
, Bod
y T
empe
ratu
re, a
nd ~
Met
ahol
ic Sc
opc
in th
c So
uthe
rn A
lliga
tor
Liz
ard
Ger
rhon
orus
rnu
l~ic
arna
~us meb
bi (
Ang
uida
e)."
M
. A. T
hcsi
s,
Cal
if.
Stat
e U
niv.
, Fu
ller
ton.
H
ollo
szy,
J.
0.
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3).
Bio
chem
ical
ad
apta
tion
s to
exe
rcis
e:
Aer
obic
met
abol
ism
. In
"E
xerc
ise
and
Spo
rt S
cien
ces
Rev
iew
s, V
ol.
I."
(J. 1
4. W
ilmor
e, e
d.).
Aca
dcm
ic P
rcss
. N
ew Y
ork,
pp.
45-
71.
lfut
chis
on, V
. H. a
nd M
iller
, K. (
1979
). A
naer
obic
cap
acity
of a
mph
ibia
ns. C
nmp.
Bio
~ht
~m
. Ph
ysio
l. 63
A, 2
1 %2
16.
Hut
chis
on,
V. H
., D
owlin
g, H
. G. a
nd V
ineg
ar,
A. (
1966
). T
hcrm
orcg
ulat
ion
in a
bro
odin
g fe
mal
e in
dian
pyt
hon,
Pj~
rhon
tnol
urus
biv
irra
rus.
Sci
ence
, N
. Y. 1
51, 6
94-6
96.
Jack
son,
D.
C.
and
Pran
ge,
H.
D.
(197
9).
Ven
tilat
ion
and
gas
exch
ange
(lu
ring
rcs
t an
d ex
erci
se in
adu
lt g
reen
sea
tur
tles.
3. c
oom
p. Ph
ysio
l. 13
4, 3
1.5-
-3 19
. Jo
hn-A
ldcr
, 11
. and
Bcn
nett
, A
. F.
(19
81).
Thc
rmal
dcp
cndc
ncc
of c
ndi~
ranc
c, ox
ygcn
co
nsum
ptio
n, a
nd c
ost
of lo
com
otio
n in
a l
izar
d. A
m. 3
. Phy
siol
. 24
1 (R
eg. I
nreg
. Cam
p.
Phys
iol.
9), R
342-
R34
9.
198
AL
BE
RT
F.
BE
NN
ET
T
Lec
hner
, A
. J.
(19
78).
Th
e sc
alin
g of
max
imal
ox
ygen
co
nsum
ptio
n an
d pu
lmon
ary
dim
ensi
ons
in s
mal
l m
amm
als.
Res
pir.
Phy
siol
. 34
, 9-4
4.
Lch
ning
er,
A.
L.
(197
5).
"Bio
chem
istr
y."
2nd
ed.
Wor
th P
ubl.
, In
c., N
ew Y
ork.
M
autz
, \Ir.
J. (
1979
). T
he
met
abol
ism
of
recl
usiv
e li
zard
s, t
he X
anlu
siid
ae.
Cop
eia
1979
, 57
7-58
4.
Mit
chel
l, G
. S.,
Gle
eson
, T. T
. and
Ben
nett
, A. F
. (19
81).
Ven
tilat
ion
and
acid
-bas
c ba
lanc
e du
ring
gra
ded
activ
ity i
n li
zard
s. A
m. 3
. Phy
siol
. 24
0 (R
eg.
Inte
g. C
omp.
Phy
siol
. 9)
, R
29-R
37.
Mob
erly
, W. R
. (19
68a)
. Th
e m
etab
olic
res
pons
es o
f th
e co
mm
on ig
uana
, Ig
uana
igua
na, t
o ac
tivi
ty u
nder
res
trai
nt.
Com
p. B
ioch
em.
Phys
iol.
27,
1-20
. M
obcr
ly, W
. R. (
1968
b). T
he
met
abol
ic r
espo
nses
of
the
com
mon
igua
na,
Igua
na i
guun
u, to
w
alki
ng a
nd d
ivin
g. C
omp.
Bio
chem
. Ph
.ysi
ol.
27,
21-3
2.
Mue
ller
, C
. F
. (1
970)
. E
nerg
y ut
iliz
atio
n in
th
e li
zard
s Sc
elop
orus
gra
cios
trs
and S.
occi
denl
nlis
. 3. H
erpe
rol.
4, 1
31-1
34.
Mur
daug
h, H
. \'. J
r. a
nd J
acks
on, J
. E. (
1962
). H
eart
rat
e an
d bl
ood
lact
ic a
cid
conc
entr
atio
n du
ring
exp
erim
enta
l di
ving
of
wat
er s
nake
s. A
m. 3
. Ph,
ysio
l. 20
2, 1
163-
1 16
5.
Nag
y, K
. A.
(197
5). W
ater
and
ene
rgy
budg
ets
of f
ree-
livin
g an
imal
s: M
easu
rem
ent
usin
g is
otop
ical
ly l
abel
ed w
ater
. In
"E
nvir
onm
enta
l Ph
ysio
logy
of
Des
ert O
rgan
ism
s."
(N. 1
:. H
adlc
y, c
d.).
Dow
den,
Hut
chis
on a
nd R
oss,
Inc
., S
trou
dsbu
rg,
Pen
n., p
p. 2
27-2
45.
Pen
ny,
D.
G.
(197
4).
Eff
ects
of
prol
onge
d di
ving
ano
xia
on t
he t
urtl
e, P
seud
ent~
~s
scri
pta
eleg
nns.
Com
p. B
ioch
em. P
hysi
ol.
47A
, 93
3-94
1.
Pou
gh, F
. H. (
1977
). O
ntog
enet
ic c
hang
e in
blo
od o
xyge
n ca
paci
ty a
nd m
axim
um a
ctiv
ity in
ga
rter
sna
kes
(Tha
mno
phis
sirr
alis
). 3. c
omp.
Phy
siol
. 11
6, 3
37-3
45.
Pou
gh,
F.
FI.
(197
8). O
ntog
enet
ic c
hang
es i
n en
dura
nce
in w
ater
sna
kes
(Nal
rix
sipe
don)
: Ph
ysio
logi
cal
corr
elat
es a
nd e
colo
gica
l co
nseq
uenc
es.
Cop
eia
1978
, 69-
75.
Pou
gh,
F.
H.
(198
0).
Th
e ad
vant
ages
of
ecto
ther
my
for
tetr
apod
s. A
m.
Nut
. 11
5, 9
2-1
12.
Pou
gh, I.'. H
. (i
n pr
ess)
. A
mph
ibia
ns a
nd r
epti
les
as l
ow-e
nerg
y sy
stem
s. I
n "B
ehav
iori
l E
nerg
etic
s: V
erte
brat
e C
osts
of
Surv
ival
." (
W. P
. Asp
ey a
nd S
. Lus
tick
, eds
). O
hio
Sta
te
Uni
v. P
ress
, C
olum
bus.
P
ough
, I.'.
13. a
nd B
usac
k, S
. D.
(197
8). M
etab
olis
m a
nd a
ctiv
ity o
f th
e S
pani
sh f
ring
e-to
ed
lizar
d (L
acer
tida
e: A
can~
hoda
cl~d
us
eryt
hrus
us).
3. th
erm
al B
iol.
3, 2
03-2
05.
Pra
nge,
H. D
. (1
976)
. E
nerg
etic
s of
sw
imm
ing
of a
sea
tur
tle.
3. e
xp. R
iol.
64,
1-12
. R
cgal
, P
. J.
(197
8).
Beh
avio
ral
diff
eren
ces
betw
een
rept
iles
and
mam
mal
s: A
n an
alys
is o
f ac
tivi
ty a
nd
men
tal
capa
citie
s.
In "
The
B
ehav
ior
and
Neu
rolo
gy
of L
izar
ds."
(N
. G
reen
berg
and
P.
McI
,ean
, ed
s).
Nat
iona
l In
stit
utes
of
Hea
lth,
Gov
ernm
ent
Pri
ntin
g O
ffic
e, W
ashi
ngto
n, D
.C.
pp.
183-
202.
R
obin
, E
. D
., V
este
r, J
. W
., M
urda
ugh,
H.
V. J
r. a
nd M
ille
n, J
. E
. (1
964)
. Pr
olon
ged
mae
robi
osis
in
a ve
rteb
ratc
: A
naer
obic
met
abol
ism
in
the
fres
hwat
er t
urtl
e. 3
. cel
l. co
mp.
Ph
.ysio
1. 6
3, 2
87-2
97.
Rub
en, J
. A
. (19
76).
Aer
obic
and
ana
erob
ic m
etab
olis
m d
urin
g ac
tivity
in
snak
es. 3
. com
p.
Plt.)
~sio
l. 109
, 14
7-1
57.
Rub
en, J
. A
. (1
979)
. Blo
od p
hysi
olog
y du
ring
act
ivit
y in
the
sna
kes hf
as~i
coph
rs~~
n~el
lr~r
~r
(Col
ubri
dac)
and
Cto
~al
us ciri
dis
(Cro
tali
dae)
. C
omp.
Bio
chcm
. Ph
.ysi
ol.
64A
, 57
7-55
0.
Kub
cn. J
. A. (
1983
). M
iner
aliz
ed ti
ssue
s an
d ex
erci
se p
hysi
olog
y of
snak
es. A
tner
. Zoo
l. 23
(2).
R
ubcn
, J.
A. a
nd B
atta
lia, D
. E. (
1979
). A
erob
ic a
nd a
naer
obic
met
abol
ism
dur
ing
activ
ity in
sm
all
rode
nts.
3. e
xp. Z
nol.
208,
73-
76.
Rub
cn,
J. A
. an
d B
enne
tt,
A.
F.
(198
1).
Inte
nse
exer
cise
and
blo
od c
alci
um
leve
ls i
n ve
rteb
rate
s. N
atur
e, L
nttrl
. 29
1, 4
1 1-
41 3
. S
chm
idt-
Nie
lsen
, K
. (19
72).
Loc
omot
ion:
Ene
rgy
cost
of
swim
min
g, f
lyin
g, a
nd r
unni
ng.
Scie
nce,
N. Y
. 177
, 222
-228
.
3. T
HE
EN
ER
GE
TIC
S O
F R
EP
TII
.IA
N AC
TIV
ITY
19
0
Seym
our,
R. S
. (19
79).
Blo
od l
acta
te in
fre
e-di
ving
sea
sna
kes.
Cop
eia
1979
, -19
C-1
07.
Seym
our,
R. S
. and
Web
ster
, M. E
. D. (
1975
). G
as tr
ansp
ort a
nd b
lood
aci
d-ba
se b
alan
ce in
di
ving
sea
sna
kes.
3. e
xp. Z
ool.
191,
169
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. Sm
ith,
E. N
. (1
975)
. Oxy
gen
cons
umpt
ion,
ven
tilat
ion,
and
oxy
gen
pls
e o
f th
e A
mer
ican
al
ligat
or d
urin
g he
atin
g an
d co
olin
g. P
hysi
ol.
Zoiil
. 48,
326
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. T
aylo
r, C
. R
. (1
973)
. E
nerg
y co
st o
f an
imal
loc
omot
ion.
In
"Com
para
ti\.e
Ph
ysio
logy
: I,
ocom
otio
n,
Res
pira
tion
, T
rans
port
and
Blo
od."
(I
,. B
olis
, K
. Sc
hniid
t-N
icls
en,
and
S. H
. P.
Mad
drel
l, ed
s).
Am
eric
an E
lsev
ier
Publ
. C
o.,
New
Yor
k, p
p. 2
342.
T
aylo
r, C
. R
., Sc
hmid
t-N
iels
en,
K.
and
Raa
b, J
. L
. (1
970)
. Sc
alin
g of
ene
rget
ic c
ost
of
runn
ing
to b
ody
size
in
mam
mal
s. A
m. 3
. Ph
j~sd
. 219,
110
.C11
07.
Taj
dor,
C. R
., Se
eher
man
, H. J
., M
aloi
y, G
. M. O
., II
eglu
nd, N
. C
. and
Kam
au, J
. $1
. %
. (1
978)
. Sca
ling
max
imum
aer
obic
cap
acity
(irO
z,,,)
to b
ody
size
in m
amm
als.
I.'e
dtf. /h-.
Fcd
n. A
m. S
ocs.
exp
. B
iol.
37, 4
73.
'I'en
iple
ton,
J. R
. (19
70).
Rep
tiles
. In
"Com
para
tive
Phys
iolo
gy o
fThc
rmor
cgnl
atio
n, \'
ol.
1.
Inve
rteb
rate
s an
d N
onni
amm
alia
n V
erte
brat
es."
(G
. C. W
hitt
ow, c
d.).
Aca
dem
ic P
rcss
, N
ew Y
ork,
pp.
167
-221
. T
ucke
r, V
. A
. (1
967)
. T
he r
ole
of t
he c
ardi
ovas
cula
r sy
stem
in
oxyg
cn t
rans
port
in
tl
thcr
mor
egul
atio
n in
liz
ards
. In
"Liz
ard
Eco
logy
: A
Sym
posi
um."
(W.
W. h
lilst
catl,
ctl.
).
Uni
v. M
isso
uri P
ress
, Col
umbi
a, p
p. 2
58-2
69.
'I'uc
kcr,
V. A
. (19
70).
Ene
rget
ic c
ost o
f loc
omot
ion
in a
nim
als.
Con
lp. B
IU~
.~P
III.
P
/rysi
ol. 3
4,
8-1 1
-846
. T
urne
r, F
. B.,
Med
ica,
P. A
. and
Kow
alew
sky,
R. W
. (19
76).
"Ene
rgy
Util
izat
ion
bya
Ilcs
crt
I.iza
rd (
Ura
sran
sbur
iana
)." U
S/I
SP
Des
ert
Bio
me
Mon
ogr.
1.
\line
gar,
A.,
Hut
chis
on,
V.
H.
and
Dow
ling,
H.
G.
(197
0). h
lcta
boli
sm,
cner
gctic
s, a
nd
ther
mor
egul
atio
n du
ring
bro
odin
g of
sna
kes
of t
he G
enus
Pyt
hon
(Rcp
tilia
, Ih
itln
c).
Zool
ogic
a 55
, 1
94
8.
Vlc
ck, D
., G
lees
on,
T.
T.
and
Bar
thol
omew
, G
. A
. (1
981)
. Oxy
gen
cons
umpt
ion
duri
ng
swim
min
g in
Gal
apag
os m
arin
e ig
uana
s and
its e
colo
gica
l cor
rela
tes.
3. co
mp.
I'/!
)hl.
, 141
, 53
1-53
6.
\\'ils
on,
K. J
. (19
74a)
. The
rela
tions
hips
of m
axim
um a
nd r
estin
g ox
ygen
con
sum
ptio
n an
d he
art
rate
s to
wei
ght
in r
eptil
es o
f th
e or
der
Squa
mat
a. C
oper
a 19
74, 7
81-7
8.5.
iV
ilson
, K. J
. (19
74b)
. The
rela
tions
hip
of o
xyge
n su
pply
for a
ctiv
ity to
hot
ly tc
mpc
ratu
re in
k)
ur sp
ecie
s in
liz
ards
. C
opei
a 19
74, 9
2S93
4.
Wils
on,
K. J
. and
Lee
, A.
K.
(197
0). C
hang
es in
oxy
gen
cons
umpt
ion
and
hcar
t ra
te w
ith
activ
ity a
nd b
ody
tem
pera
ture
in
the
tuat
ara,
Sph
enod
on p
uncr
atum
. C
nmp.
Bio
chn.
P
l~ys
iol.
33, 3
1 1-3
22.
iVils
on, K
. J. a
nd L
ee, A
. K. (
1974
). E
nerg
y ex
pend
itur
e of
a la
rge
herb
ivor
ous
linr
d. C
opci
ct
1974
,338
-348
. W
ood,
S. C
. and
Joha
nsen
, K
. (19
74).
Res
pira
tory
ada
ptat
ions
to d
ivin
g in
thc
Nile
mon
itor
lizar
d, V
aran
us n
ilori
cus.
3. co
mp.
Phy
siol
. 89
, 14
8-15
8.
Woo
d, S
. C.,
Joha
nsen
, K.,
Gla
ss, 1M. L
. and
hla
loiy
, G. M
. 0. (
1978
). A
erob
ic m
eti~
bolis
rn
of th
e liz
ard
Var
anus
exa
n~he
ma~
icus
: Eff
ects
of
activ
ity, t
empe
ratu
re, a
nd s
ize.
3. c
otnp
. I'l
?ysio
l. 12
7, 3
3 1-3
36.