NUTRITIONAL STRATEGIES IN MAMMALS

EEOB 625 – 18 February 2004

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Assigned Reading: Foods & Feeding, Chapter 6 from Feldhamer et al. (1999) available on Electronic Reserve (Instructions on Course Website)

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Components of a Nutritional Strategy

• Strategy: A suite of adaptations providing a solution to a major “problem of existence”

1) nutrition, 2) survival, & 3)reproductionComponents of a Nutritional Strategy:

• Foraging and anti-predation behavior

• Feeding habits or diet

• Morphological & Physiological Adaptations

Feeding Habits of Mammals& their taxonomic distribution (Zoo 625)

Feeding Habit Number of Percent of

Orders Species

• Herbivory 10 40• Frugivory, Graniv., Nectivory 5 4

• Carnivory 4 12

• Planktonivory ? (Krill feeders) 2 <1

• Insectivory 10 33

• Omnivory 7 10

Feldhammer Fig. 6.1

Feeding & Locomotory Adaptations

• An important “animal” relationship

between feeding and locomotion

• Traditional basis for grouping mammals into orders by adaptive zone classification (17 of 26 orders), but will this survive cladistic analysis?

• Feeding & locomotion provide solutions to two of three major problems of existence:

Nutrition, Survival (antipredation) & Reproduction

Analysis of Feeding and Related Adaptations

Feldhamer’s Approach: Foods and morphological adaptations for capture, mastication, & digestion; e.g., herbivore, carnivore, insectivore

Alternative Approach: One based on:1. Distribution & abundance, including seasonal variation

2. Availability: e.g., Low in nocturnal flying insects

3. Quality: e.g., High (in protein) in insects, fleshy prey, & seeds and nuts, Low in leave & stems of plants

• The problem of toxicity in leaves of some plants

Herbivory & The Problem with Cellulose

Cellulose: 1) Ultra-abundant? plant cell walls & fiber

2) High in energy?polycarbohydrate

3) Unavailable ?

Cellulase: Origin & taxonomic distribution?

Found only in bacteria & some protozoans

Morphological & Physiological Adaptations for Herbivory

1. Finding, securing, & masticating food

2. Providing for (?) anaerobic bacteria &

protozoans (microflora)

3. The problem of plant toxins

Dental adaptations for herbivory Incisors, molar occlusal surfaces, & masseter

Fig. 6.6

Felids: highly derived carnivores

Carnassials & claws

Schwartz & Schwartz (1959)

Fig. 6.2

Basics of Ruminant Digestion

• Evolutionary response to toxins or cellulose?• Anatomy of the ruminant “stomach” (R-R-O-A)

• Cellulose + microflora SCFA & microflora

- hydrolysis of cellulose to glucose

- glucose short-chain fatty acids (SCFA) & ____?

- microflora are digested in the abomasum

Recycling of salivary urea to fertilize rumen bacteria• Foregut & hindgut fermentation: deer vs.horses

Recycling of Urea in Ruminants

Fig. 6.9