Biological Anthropology/Unit 2: Non-human Primates/Modern Primates

= The modern non-human primates =

Why is primatology in anthropology?
Anthropology is the study of humans and the human condition. Humans are primates. We belong to the taxonomic order Primates. This order encompasses humans as well as what we call non-human primates. Non-human primates are our closest biological and evolutionary relatives. So, we study them in anthropology in order to learn more about ourselves.

Primates: common traits
Because humans share an evolutionary history with non-human primates, we all share certain biological and behavioral traits with them.

This is because these are the traits we all inherited from the ancestral primate we share.

The biological traits that primates share include:

Body

 * Primates have a flexible and generalized limb structure that's able to move readily in many directions.

Compare the flexibility of the spider monkeys on the left with the horse on the right.



Hands



 * Primates have prehensile hands (and most of them have prehensile feet also). This means that they have the ability to grasp and manipulate objects.
 * Primates have 5 digits (pentadactyly) on their hands and feet. Note that a few primates, like spider monkeys, have what are called vestigial thumbs. This means that they have either a very small or non-existent external thumb (but in that case, they will still have a small internal thumb bone).
 * Primates have flattened nails instead of claws.
 * Primates have very sensitive tactile pads on their digits with fingerprints (dermatoglyphs). Some monkeys, like woolly monkeys, have similar pads with fingerprints on the ends of their prehensile tails. Therefore, it functions just like another hand.

Check out the similarities and differences of the various primate hands in the image on the right.

Teeth

 * Primates have heterodonty, meaning that they have different teeth that perform different tasks when processing food via biting or chewing. With this, they have an ability to have a more generalized diet (compared to a specialist diet), meaning that they have more dietary flexibility. Why would this be a good thing to have?

Compare the teeth of the cayman (a relative of crocodiles and alligators) with the human teeth on the right. While the cayman's teeth do vary in size, they don't vary in structure. However, the human has incisors, canines, premolars, and molars -- all of which perform different food processing tasks.



Senses

 * Compared to most other mammals, primates have an increased reliance on vision and a decreased reliance on their senses of smell and hearing.
 * Associated with this are their smaller, flattened noses, loss of whiskers, and relatively small, hairless ears.
 * Also associated with this are their foward facing eyes with accompanying binocular or stereoscopic vision. This type of vision means that both eyes have nearly the same field of vision with a lot of overlap between them. It provides wonderful depth perception (but a loss of peripheral vision).

Note first how the eyes of the monkey on the left are more front-facing than the eyes of the cow on the right. Also note how flat the monkey's nose is and how small its ears are, when compared to those of the cow.



Brain

 * Compared to other mammals, primates have a more expanded and elaborate brain.

Compare the complexity of the human brain on the left to the cat brain on the right.



Life history

Life history refers to the pattern that an organism takes from conception to death.

When compared to other mammals, primates have :


 * longer gestation (pregnancy) periods
 * reduced number of offspring (usually one, but some species commonly have twins)
 * delayed maturation, whith a long infancy and juvenile learning period
 * extension of the entire lifespan

Behavior
The behavioral traits we share include:


 * a greater dependence on flexible, learned behavior
 * a tendency to live in social groups



The living primates and taxonomy

 * Watch this slide show to learn all about our friends (and relatives), the non-human primates.

See the notes at the bottom of each page for assistance with pronunciation of technical terms.

Additional information on the slides

Page 1:

Taxonomyis the science of classifying organisms.

Page 21:

Notice on the image that under "Ring-tailed lemur" it says "Lemur catta". That's the scientific name for that type of lemur (using a two-name system called binomial nomenclature). Lemur is the name of its genus and catta is the name of its species. When writing scientific names, remember that they are always in italics and that the genus name is always capitalized, but the species name is not.


 * Explore primate taxonomy with thisinteractive primate family tree.

For the full taxonomic classification of humans, check out this page.