Approximately 4 million years ago a wonderful evolutionary phenomenon was happening in Africa. Early hominids, mans ancestors, were beginning a giant leap in their evolution. These hominids were moving out of the forest and beginning to walk upright, out on the open plains (Fagan, 98). This change from quadrupedalism was the most significant adaptation that ever happened to these early hominids. It caused many adaptations that make man what he is today. This process occurred in early hominids for many different reasons, each reason helping to perfect the upright walking posture. Bipedalism is thought to have occurred because of changes in environment, feeding habits, thermal regulation, and behavioral mechanisms.During the time of the late Miocene epoch, about 10 to 7 million years ago the earth was changing. This change caused a fall in temperatures, which resulted in forest depletion, increasing the percentage of open environments in tropical latitudes. Forest depletion made the species that survived the temperature change adapt to become mostly terrestrial. In fact 40 or more extinct primates including hominids had to adapt to a terrestrial life style. Approximately 4 million years ago this change led to bipedalism in hominids because of problems quadrupeds had moving on the ground (Fagan, 98). Bipedalism was much more efficient when the African plains dried up and resources were very scarce. Long distance traveling on the ground was favored by bipeds (Leney, 00).In 1996 Kevin Hunt proposed a feeding hypothesis on why bipedalism ocurred. It stated that 80% of the time chimpanzees feed, they are exhibiting a bipedal locomotion (Jacobs, 90). This occurs when chimps feed on the fruits of small, open-forested trees and shrubs. When they feed, chimps stand on 2 legs and reach up to the fruit with their forearms. They usually balance themselves on branches or on the ground and hold on to higher limbs in an arm like fashion ...
