1. Modes of Primate Locomotion

2. Locomotion refers to how a primate gets around. A mode of locomotion, as used here, refers to how a primate most frequently moves around. Many primates employ multiple modes of locomotion. A mode of locomotion generates selective forces which change the body.

3. Quadrupedalism Quadrupedalism does not simply mean that a primate moves with hands and feet touching the ground. It assumes two distinctive forms: arboreal quadrupedalism and terrestrial quadrupedalism.

4. Arboreal Quadrupedalism Examples: Langurs, Howler Monkeys, Guenons. Occipital condyle/formen magnum is located in the rear of the skull Cranial vault is low but cranium is long Bones of the pelvis are long and narrow Shoulder harness is located below the spine vertebrae are not markedly different in size Chest is narrow Hindlimbs and forelimbs are equivalent in size and length

5. Terrestrial Quadrupedalism

6. Vertical Leaping Lengthened and fused tarsal bones Hind limbs are much longer than forelimbs Feet much larger and longer than hands

7. Knuckle Walking Gorilla

8. Brachiation Rib cage is broader than that of quadrupeds. Spine of some brachiators has one fewer vertebra than quadrupeds Neck has one more cervical vertebra over quadrupeds

9. Quadrumanous/ Quadrumanual Essentially, the anatomy is analogous to that of a brachiator, but the adult Organutan is too large to brachiate. Male Orangutans in particular get so large that they have to clamber to the ground and move to the next tree by fist walking.