Anthropology P380: Prehistoric Diet and Nutrition
Lecture 3: Our Primate Heritage
We are members of the Primate Order -- first primates originated over 65 million years ago (little warm-blooded mammals running around the toes of the dinosaurs). Some of the very basic aspects of our physiology that relate to dietary adaptations can be traced to our primate heritage.
Primate Diet:
- omnivorous (vegetable, animal & insect)
- Most (90%) eat at least some fruits & young leaves.
- Over 30% get some flesh/eggs/insects
- eclectic (wide variety of foods):
- Most are quite generalized (capable of eating a wide range of foods), but some have evolved into specialists --
- selective (use eyes/hands/taste to choose foods)
- binocular vision
- manual dexterity
- larger brains, relative to body size, compared to other animals
Coevolution with Angiosperms: What this suggests about Primates is that they evolved a dependence on fruit and leaves. In fact, a major theory for the origins of Primates is that they coevolved with the Angiosperms -- the flowering plants -- in the Late Cretaceous period. Primates eat a wide range of foods, and are omnivorous, in general. But most eat at least some fruit, and Primates have evolved real preference for certain types of fruits (e.g. compared to sympatric fruit bats, birds, or squirrels) -- Primates often prefer medium-sized, ripe, sweet fruits (yellow, orange, red) (vs. Tropical forest birds that often select larger, oilier fruits... smaller birds go for smaller fruits and berries... c.f.. research by Mark Leighton in Borneo).
A plant's perspective: it creates a seed, which it needs to survive and reproduce. It wants to distribute its seeds as widely as possible, to give them many opportunities to take root -- needs seed dispersal . But, at the same time, it wants to protect that seed from seed predators. What's a poor Parent plant to do? Think of fruits as the reproductive package of a plant.
Mechanical Solution: expensive !
- spurs, spikes, spines , hard internal shell (e.g. nut) to protect seed, yet help disperse them too
- or "flood the market" (like figs) and just overwhelm predators, both by having all fruit ripen at the same time ("masting" phenomenon of trees in forests), and by having many small, hard seeds in fruit, so many will pass through digestive system.
- (n.b. growing all these parts can be expensive for a plant -- is typical of woody plants in nutrient-rich soils)
Chemical Solution: cheap!
- Attract seed dispersers with fleshy fruit covering (or oil-rich aril)
- sugars!
- oils!
- Protect seed from with chemicals "secondary compounds"
- e.g. TOXINS (like Alkaloids = bitter taste)
- or digestion inhibitors (Tannins = astringent taste)
- or block enzyme function (trypsin inhibitors in legumes) (n.b. secondary compounds are a relatively cheap way for plants to avoid predation)
"The Omnivore's Dilemma"
How are Primates:to cope/survive? Need basic energy and nutrients to survive, and must eat a wide array of different food types.Yet must try to avoid the "anti-nutrients."
- equiped to try new food sources, and have vast array of choices
- yet novel foods are potentially dangerous foods... (Psychologist Rozin says conservatism of human cultural food traditions linked to this...)
Answer: Learn to be very selective. Tools? The SENSES.
Higher primates: the Anthropoidea (monkeys, apes and humans) are particularly well-adapted for feeding off of Angiosperms:
- Color vision (diurnal; distinguish ripe fruits & flowers)
- Sense of smell reduced (dry nose and no whiskers)
- taste = ways of learning about the foods
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Last updated: 6 September, 1999
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Copyright 1998 Jeanne Sept
