Primate Feeding Ecology Flashcards
Foraging Strategy
The types of food resources used and how primates search for them - Primates must find a MIX of food; sources of protein, carbohydrates, vitamins and minerals
Nutritional Requirements
At its simplest all mammals must have:
- source of energy (carbohydrates, fats or even protein)
- ability to maintain, repair, and build tissue (protein)
- regulate body processes (vitamins and minerals)
How Primates meet their Carbohydrate needs:
- FRUIT: especially ripe fruit, lots of sugar not alot of fiber-high quality rich in carbs (energy) low in fiber (easy to digest)- not mechanically challenging-usually
- TREESAP/GUM: (marmosets) rich in carbs BUT require adaptations to digest efficiently - long ceacum
- INSECTS: “perfect food” (protein, fat, carbs) BUT hard to catch
- SEEDS: good fat source BUT mechanically challenging
How Primates meet their Protein needs:
- VERTEBRATES (animals)
- INVERTEBRATES (insects)
- costly to find animals/insects and non-social insects dont provide large amt of food
- LEAVES & FLOWERS
- leaves are considered “lower-quality” harder to digest- high fiber; flowers are seasonal
How Primates meet their Vitamin and Mineral needs
- VITAMINS: (Vit C = Fruit) Haplorrhine primates cannot make on their own -> Scurvy
- MINERALS: -Geophagia (eat soil/termite mounds/clay), de-toxify leaf toxins, add minerals, help eliminate internal parasites (endoparasites)
Constraints on Feeding Ecology
Getting the right mix of food greatly complicates foraging strategy:
Chemical defenses of potential food items
- Limited availability; only stay ripe for so long
- Distribution of foods: leaves-nearly uniform, insects-random, fruit-clumped
- Fiber content
- Incomplete Nutrition
- Feeding Competition
Theory of Primate Diets:
Important factors affecting dietary choices (?)
- Body size
- Habitat (biome)
- Morphology (what teeth look like, presence of sacculated stomach)
- Sociality
Effects of size
A primate’s body size puts considerable restrictions on its feeding options, ecological options, eg locomotion and diet:
- Most differences in primate behavior and ecology are correlated w/absolute body size
- How big you are will predict if primate primarily arboreal or terrestrial: small body size=arboreal (unless have lots of adaptations-> orangutan); large body size=terrestrial
- Most primates are arboreal -> impacts foot morphology
- Most terrestrial primates are fairly lrg; 20+kg (44+lbs)
- Body size also affects where primates look for food and how they move w/in a particular habitat: sm=tend to leap; lrgr=tend to use suspensory behaviors and bridging
Basal Metabolic Rate (BMR)
the amt of energy consumed by a resting organism simply to maintain its basic functions
Kleiber’s Rule
Basal metabolism does not scale directly w/ body size - it scales to the power of 0.75
This means the BMR relative to body size actually *decreases as we go from smaller to larger animals
BMR for small vs larger animals:
- Relative to body wt, sm animals require more energy than lrgr animals
- This has a major effect on foraging strategies of lrg vs sm primates:
- Lrg animals need more food overall, but have lower energy requirements per unit body wt than sm animals
- Sm animals need less food overall, but have higher energy requirements per unit body wt than lrgr animals
- lr & sm animals have diff “foraging strategies”
Smaller primates (<500grams) : Galago
Require: less amt of food overall than lrgr primates, but food need to be “high quality” eg: energy rich and easy to digest
-insects are ideal; can provide all nutrients - carbs, protein, vitamins, ect..
Medium primates (500grams-1kg): Squirrel Monkey
- Makes it hard to get all energy requirements just from insects
- Must also add more abundant energy sources-gums, flowers, fruits
Larger primates (>1kg): Two strategies: Colobinae & Gorillas, Chimpanzees
Require:
- More food overall than small primates
- Protein source can be “lower quality” eg less energy-rich and more fibrous
* morphological adaptations such as sacculated stomachs (colobinae) or more volume in lrg intestine to digest leaves in their diet (gorilla) - OR high quality using behavioral strategies
* mixed foods: leaves, animals, fruits AND behavioral adaptations - tool use (chimpanzee- may maintain a relatively lrgr more expansive brain)
What we know in a general sense based on body size:
- Sm primates tend to be insectivores
- Med primates tend to be omnivores (eat mix fruit, leaves, insects) or frugivores
- Lrg primates are either folivores OR have traits (morphological &/or behavioral) allowing them to maintain a higher quality diet including fruits
