Fighting and an Incipient Notion of Territory in Male Tree FrogsAuthor(s): Bertha LutzSource: Copeia, Vol. 1960, No. 1 (Mar. 25, 1960), pp. 61-63Published by: American Society of Ichthyologists and HerpetologistsStable URL: http://www.jstor.org/stable/1439858 .Accessed: 21/06/2011 16:06

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HERPETOLOGICAL NOTES HERPETOLOGICAL NOTES

TABLE I AUTOPSY DATA ON 8 Sternothaerus odoratus, CAPTURED ON

APRIL 30 AND SACRIFICED MAY 3

Cara- Body Ovarian Ovi- Turtle Number pace

W O vian Turtle Number Legt Weight Weight Egari ducal

(mm.) (g.) (g.) Eggs

1 94 139 9.5 10 0 2 84 101 6.1 4 0 3 87 112 8.4 7 0 4 97 134 8.1 6 0

Mean 90.5 121 8.0 6.8 5 92 107 3.5 0 3 6 93 134 4.2 0 3 7 88 122 5.0 0 4 8 92 132 5.3 5 4

Mean 91.2 124 4.5 3.5

* Straight line measurement. ** Refers only to large eggs.

TABLE I AUTOPSY DATA ON 8 Sternothaerus odoratus, CAPTURED ON

APRIL 30 AND SACRIFICED MAY 3

Cara- Body Ovarian Ovi- Turtle Number pace

W O vian Turtle Number Legt Weight Weight Egari ducal

(mm.) (g.) (g.) Eggs

1 94 139 9.5 10 0 2 84 101 6.1 4 0 3 87 112 8.4 7 0 4 97 134 8.1 6 0

Mean 90.5 121 8.0 6.8 5 92 107 3.5 0 3 6 93 134 4.2 0 3 7 88 122 5.0 0 4 8 92 132 5.3 5 4

Mean 91.2 124 4.5 3.5

* Straight line measurement. ** Refers only to large eggs.

the remaining four contained large ovarian eggs that seemed ripe and ready to ovulate (Table 1). Turtle number 8 contained both oviducal eggs and large ovarian eggs. These data suggest that ovulation in this species occurs in late April or

early May at this latitude; turtle number 8

probably had only partially ovulated by May 3. In only one of the turtles was there any evidence of calcification of the shell of the oviducal eggs. Expulsion of the egg from the ovary appears to result in a considerable decrease in weight of the

ovary itself, which is not surprising in view of the fact that 10 viable eggs removed from 3 fe- males on June 9, 1955, averaged 4.02 ? 0.08 grams.

The actual date of egg laying in southern Wis- consin is unknown, although natural nests were discovered on June 29 (Edgren, Chicago Acad. Sci., Nat. Hist. Misc., 53:1, 1949). In addition, since viable eggs were removed from turtles on June 9 (Edgren, Chicago Acad. Sci., Nat. Hist. Misc., 152:1, 1956), natural oviposition probably takes place in middle or late June. Thus the life of the egg in the oviduct of this species must be between 5 and 8 weeks.-RICHARD A. EDGREN, Division of Biological Research, G. D. Searle and Co., Chicago, Illinois.

FIGHTING AND AN INCIPIENT NOTION OF TERRITORY IN MALE TREE FROGS.- The notion of territory and the habit of fighting between males are not generally associated with frogs but rather with birds and mammals. Never- theless, there are rudiments of their occurrence among neotropical frogs. Hyla faber (Fig. 1), one of the largest tree frogs in Brazil, has acquired the interesting habit of building nest-pans for spawning. This habit is tied to a pattern of nup- tial behavior that is more complex than the usual reproductive behavior of frogs. It involves a rudi-

the remaining four contained large ovarian eggs that seemed ripe and ready to ovulate (Table 1). Turtle number 8 contained both oviducal eggs and large ovarian eggs. These data suggest that ovulation in this species occurs in late April or

early May at this latitude; turtle number 8

probably had only partially ovulated by May 3. In only one of the turtles was there any evidence of calcification of the shell of the oviducal eggs. Expulsion of the egg from the ovary appears to result in a considerable decrease in weight of the

ovary itself, which is not surprising in view of the fact that 10 viable eggs removed from 3 fe- males on June 9, 1955, averaged 4.02 ? 0.08 grams.

The actual date of egg laying in southern Wis- consin is unknown, although natural nests were discovered on June 29 (Edgren, Chicago Acad. Sci., Nat. Hist. Misc., 53:1, 1949). In addition, since viable eggs were removed from turtles on June 9 (Edgren, Chicago Acad. Sci., Nat. Hist. Misc., 152:1, 1956), natural oviposition probably takes place in middle or late June. Thus the life of the egg in the oviduct of this species must be between 5 and 8 weeks.-RICHARD A. EDGREN, Division of Biological Research, G. D. Searle and Co., Chicago, Illinois.

FIGHTING AND AN INCIPIENT NOTION OF TERRITORY IN MALE TREE FROGS.- The notion of territory and the habit of fighting between males are not generally associated with frogs but rather with birds and mammals. Never- theless, there are rudiments of their occurrence among neotropical frogs. Hyla faber (Fig. 1), one of the largest tree frogs in Brazil, has acquired the interesting habit of building nest-pans for spawning. This habit is tied to a pattern of nup- tial behavior that is more complex than the usual reproductive behavior of frogs. It involves a rudi-

mentary sense of territory and fighting among the males.

A good opportunity for observing and photo- graphing Hyla faber and its activities was af- forded the author, her brother, Professor Gualter A. Lutz, who took the photographs, and our as- sistant, the late Joaquim Venancio, during the summer of 1951, at the "Acude da Solidao" in a clearing at the edge of the montane Tijuca forest, outside Rio, at approximately 380 m. of altitude. The observations were continued by the author in 1959.

This irregularly elongate pool is formed by a brook coming down from the mountains. Form- erly it was a small marsh but the pool was deep- ened, a dam was built at the lower end, and an open path planted with trees provided around it. Ornamental vegetation was later brought in from outside. The place is protected against depreda- tion, as it is on government land and has a resi- dent guard. A colony of Hyla faber has become established beside this pool; this is apt to occur when a quiet artificial pond is provided in a

place, such as the edge of montane forest, poorly endowed by nature with the right biotope for the larvae. Similar colonies have been observed else- where, for instance in the Biological Station of

Paranapiacaba, at Alto da Serra, near the city of Sao Paolo, at 800 m. of altitude.

The nests are rounded pans, mostly with raised clay walls, built inside pools of standing water, either at the edges or in shallows (Fig. 3). They have been known for a long time (Goeldi, Proc. Zool. Soc. London, 1895:89-97), but the details concerning their building were not all discovered nor quite accurately presented. Contrary to Goeldi's statement, it is the male, not the female, who does the building.

The male builds the nest by getting into the water, sitting in a shallow place and circling

mentary sense of territory and fighting among the males.

A good opportunity for observing and photo- graphing Hyla faber and its activities was af- forded the author, her brother, Professor Gualter A. Lutz, who took the photographs, and our as- sistant, the late Joaquim Venancio, during the summer of 1951, at the "Acude da Solidao" in a clearing at the edge of the montane Tijuca forest, outside Rio, at approximately 380 m. of altitude. The observations were continued by the author in 1959.

This irregularly elongate pool is formed by a brook coming down from the mountains. Form- erly it was a small marsh but the pool was deep- ened, a dam was built at the lower end, and an open path planted with trees provided around it. Ornamental vegetation was later brought in from outside. The place is protected against depreda- tion, as it is on government land and has a resi- dent guard. A colony of Hyla faber has become established beside this pool; this is apt to occur when a quiet artificial pond is provided in a

place, such as the edge of montane forest, poorly endowed by nature with the right biotope for the larvae. Similar colonies have been observed else- where, for instance in the Biological Station of

Paranapiacaba, at Alto da Serra, near the city of Sao Paolo, at 800 m. of altitude.

The nests are rounded pans, mostly with raised clay walls, built inside pools of standing water, either at the edges or in shallows (Fig. 3). They have been known for a long time (Goeldi, Proc. Zool. Soc. London, 1895:89-97), but the details concerning their building were not all discovered nor quite accurately presented. Contrary to Goeldi's statement, it is the male, not the female, who does the building.

The male builds the nest by getting into the water, sitting in a shallow place and circling

Fig. 1.-Hyla faber Wied. Fig. 1.-Hyla faber Wied.

61 61

COPEIA, 1960, NO. 1

Fig. 2.-A male Hyla faber starting to build the nest. Note the spread of the hands.

When the nest is finished, and sometimes even before, the male starts singing, sitting either on the rampart, inside the cavity, or even outside it, but in the vicinity. Females ready to spawn seem to be attracted by the drumming of the males. They approach, halting now and then in a peculiar position, sitting with the fore part of the body elevated. After a time they get into the nest and eventually swim up to the male from behind and lay a hand on his back. At first he just goes on calling, then suddenly he turns and seizes the female.

Fights between male Hyla faber were witnessed several times. They may break out in the nest or outside it. The fighting males encircle each other's heads and necks with the arms and place their hands into positions that permit them to drive the sharp, curved pollex rudiments into the

Fig. 3.-Nests of Hyla faber in different stages of construction at the edge of a pool.

around, thus forming a rounded cavity and grad- ually deepening it. He forms the walls by pushing up the clay and patting it onto the edges of the nest with hands (Fig. 2). Occasionally, the frog goes under, brings material up on the snout, and pushes it onto the wall with the hands. It is difficult to see into the muddy hole, but the feet are probably used in the same manner as the hands. The finished and perfect nests are rounded and from 27 to 33 cm. in diameter, and from 7.5 to 9 cm. deep. The rampart may rise some 5 to 7 cm. above the water.

enemy. Meanwhile, they may wrestle with the long legs and try to push each other under while

keeping their own nostrils above water. Some- times they thrash around; at other times they lie quite still with the legs drawn up under the body, which is as much inflated as possible. If one is stronger, or more agile, he gets on top and seems to try to drown the other.

When the fight begins inside the nest the frogs may fall out and continue to fight, either on shore (Fig. 4), or in the pond; sometimes they break off and move away. A pair of fighters can

62

ICHTHYOLOGICAL NOTES ICHTHYOLOGICAL NOTES

Fig. 4.-Two male Hylafaber fighting on shore. The peculiar position of the hands permits driving in the pollex rudiments. All photographs by Prof. Gualter A. Lutz.

Fig. 4.-Two male Hylafaber fighting on shore. The peculiar position of the hands permits driving in the pollex rudiments. All photographs by Prof. Gualter A. Lutz.

be lifted up together and moved so as to be examined. It is then seen that the skin round the rudimentary pollex is pushed down and the

sharp curved point is bare. The fighters may have both their pollices dug into the foe. If one

gently lifts a pollex out, it is promptly pushed in again. It is only after some handling that they seem to realize the change, break apart, and hop away. One of a pair of fighters, thus lifted out, proved to be a male that had been singing, the

night before, inside the nearest nest. He was

easily recognized by his individual pattern. The seriousness of the wounds depends on the

point reached. On one occasion a dead male Hyla faber was pulled out of the pond and showed a trickle of blood just beside the tympanum. In prolonged amplexus the female may also be severely wounded by the pollices and perish in consequence.

be lifted up together and moved so as to be examined. It is then seen that the skin round the rudimentary pollex is pushed down and the

sharp curved point is bare. The fighters may have both their pollices dug into the foe. If one

gently lifts a pollex out, it is promptly pushed in again. It is only after some handling that they seem to realize the change, break apart, and hop away. One of a pair of fighters, thus lifted out, proved to be a male that had been singing, the

night before, inside the nearest nest. He was

easily recognized by his individual pattern. The seriousness of the wounds depends on the

point reached. On one occasion a dead male Hyla faber was pulled out of the pond and showed a trickle of blood just beside the tympanum. In prolonged amplexus the female may also be severely wounded by the pollices and perish in consequence.

Amplexus is very persistent, the male holding the female forcibly. During mating inside the nest, he repeatedly presses her down so hard that she is pushed under. While trying to come up she sometimes brings sand or clay from below and

spreads it with her hands along the inside of the rim. This is the only contribution of the female towards building that we have observed. It may also be the origin of Goeldi's statement, in his second observation, "that the male frog is present during the erection of the nest or pool, in a

perfectly passive manner, however, that is sitting on the back of the female."

Breder (Bull. Amer. Mus. Nat. Hist., 86:375- 436, 1946) observed the nests of Hyla rosenbergi Blgr. in Panama, but does not mention fighting between the male frogs.-BERTHA LUTZ, Natural- ist, Museu Nacional, Rio de Janeiro, Brazil.

Amplexus is very persistent, the male holding the female forcibly. During mating inside the nest, he repeatedly presses her down so hard that she is pushed under. While trying to come up she sometimes brings sand or clay from below and

spreads it with her hands along the inside of the rim. This is the only contribution of the female towards building that we have observed. It may also be the origin of Goeldi's statement, in his second observation, "that the male frog is present during the erection of the nest or pool, in a

perfectly passive manner, however, that is sitting on the back of the female."

Breder (Bull. Amer. Mus. Nat. Hist., 86:375- 436, 1946) observed the nests of Hyla rosenbergi Blgr. in Panama, but does not mention fighting between the male frogs.-BERTHA LUTZ, Natural- ist, Museu Nacional, Rio de Janeiro, Brazil.

Ichthyological Notes FOUR SHARK ATTACKS ON THE WEST the sixty-mile stretch of beach between Sara-

COAST OF FLORIDA, SUMMER 1958.-Dur- sota and Sanibel Island on the lower West Coast ing the summer of 1958, four cases of shark at- of Florida. The water temperature in these four tack occurred within a period of five weeks along cases was approximately 30? C. The case of

Ichthyological Notes FOUR SHARK ATTACKS ON THE WEST the sixty-mile stretch of beach between Sara-

COAST OF FLORIDA, SUMMER 1958.-Dur- sota and Sanibel Island on the lower West Coast ing the summer of 1958, four cases of shark at- of Florida. The water temperature in these four tack occurred within a period of five weeks along cases was approximately 30? C. The case of

63 63