There are a number of distinctive features of human species which make it different from his close relatives, the anthropoid apes (for example, gibbons, orangutan, gorilla and chimpanzee).
1. The human species walks erect on two feet (bipedal). He is terrestrial, gregarious (lives in community) and omnivorous. On the other hand, the apes are semi-erect, for-handed, tree-dwellers and less gregarious. Legs in man are 30% longer than the arms.
2. Hands of man are not specially modified as we find in bats and whales. Thumbs are better developed. Arms of ape reach below the knees. Apes walk with a bent posture and balance themselves on the knuckles of their hands. The hind limbs of the apes enable them to grasp an object. But the feet of man act as a platform and are suitable for palntigrade (walking on the soles of feet) type of locomotion.
3. The thumb of ape is short. In man the thumb is longer and it is more mobile to close in on other fingers. As a result, the hand can be used for a variety of purposes.
4. Bipedal locomotion in man leaves the arms and hand free for carrying or doing things, the movable joints of arms, wrists, hands and fingers afford a great deal of versatility and the forelimbs can be used with great dexterity for handling tools.
5. Teeth of an (incisor, canine, premolar and molar) are smaller and more ordered. The jaws and nose are smaller than those of gorilla. The capacity of the human brain box is 100cc; in gorilla it is 510cc.
6. The space between the two eyes is close enough for distance perception and stereoscopic vision.
7. The retina in the eye of man is provided with cone cells which perceive different colors.
8. In man the brow ridge is not as prominent as in gorilla.