Primate Notes

Primates include the most familiar of the placental mammals.

• Most primates live in tropical or sub-tropical regions of the Americas, Africa, and Asia.

So…what makes a primate a primate?

• 3 kinds of evidence are considered:

– I. Skeletal features– II. Primate adaptations– III. Primate behavior

I. Skeletal features related to teeth and snout:

• Shortened snout. Primates rely less on their sense of smell and more on vision.

• Primates also have a reduced number of teeth as compared to other mammals.

Several types of teeth:

• Incisors, canines, premolars, and molars…just like in humans

• With different types of teeth, they can eat a variety of foods and also process food more efficiently.

• They have incisors for biting, canines for shearing, plus premolars and molars for crunching food into digestable packages.

Skeletal Features related to eyes and ears.

• Forward-facing eye orbits. • Primates have an increased emphasis on vision, so the

eyes are in the best position to take in a large amount of visual stimuli.

Stereoscopic vision (Huh?!?)• This means that the fields of vision provided by each eye overlap,

resulting in depth perception.

• This is extremely useful for forest-dwelling primates, as it lets them judge how far away they next branch is as they are moving from tree to tree.

Skeletal Features related to arms and legs• Clavicles (collarbone). Primates have very extensive shoulder

motion because the clavicle provides the only bony link between the upper limb and the trunk.

• 2 separate bones in the forearm and lower leg. Having 2 bones allows for better limb motion and more precise movements.

Skeletal features related to fingers and toes

• Nails instead of claws. Nails allow primates to manipulate objects more easily.

Increased thumb mobility (dexterity).• This also helps primates to manipulate objects. • Grasping feet. Primates have more big toe mobility for grasping

and climbing. • The only exception is humans. • We do not have the ability to grasp because our feet are designed

as a platform for walking.

II. Primate Adaptations

• Trend toward a more vertical posture.

Trend toward different use of forelimbs and hindlimbs.

• Primates use their limbs for more than just locomotion (moving around).

• Trend toward longer lives with longer periods of infancy, childhood, and adulthood.

• Longer lives and longer life stages are good for increased growth.

Primates have larger brains for their body size than most other mammals do.

• They are born with brains that still need to develop quite a bit outside the mother’s body.

• Primates also spend a lot of time learning skills and strategies for food gathering and survival from their mothers and others in their social groups.

Trend toward enlarged brains with increased areas for vision and reduced areas for smell.

III. Primate Behavior• Primates spend their time using their limbs to climb in trees by

grasping with their hands and feet. • They also use their hands to bring food to their mouth for feeding. • Being a part of social group life, building and reinforcing bonds

between individuals and learning from their mothers and others.