Many people think that our high intellect or the ability to grasp items with our opposing thumbs is what sets us apart from other primates. All primates share the grasping thumb, and the difference between a human brain and an ape brain is not as great as people perceive it to be. The human brain is basically a bigger and more complicated version of a chimpanzee brain.
The main difference between humans and primates are that humans can walk on two legs. Although Homo sapiens arenâ€™t the only primates to walk on two feet, no other primate does it so often. Many evolutionary biologists and anthropologists have come up with many reasons as to why hominids started to walk upright. There are many different explanations as to why hominids started to walk upright. One of the main hypothesized causes of bipedalism is that walking on two legs is a more energy efficient way of moving around than a quadruped. When hominids first had to adapt to an open environment the ones that could walk on two feet would be able to search for food longer.
Another reason why bipedalism came about is that the hands would not have to help the hominid walk and hominids would be able to make tools and gather food more efficiently. Anthropologists and biologists now agree that upright posture and walking on two legs was the crucial and probably first major adaptation associated with