The accepted theory of human evolution for the last three-quarters of a century has been the so-called "Savanna Hypothesis". These hypotheses are the ones we all hear about in popular media and are taught in schools. They state that humans evolved their unique characteristics on the grasslands of the African savannas.

The theory argues that bipedalism grew out of the need to look farther over the grasses, and move faster. This, in turn led to the use of tools, since both hands were free. Loss of body hair, acquisition of subcutaneous fat and sweating, are explained as methods of thermoregulation (maintaining even body temperatures). The ability for speech may have come from the anatomical changes associated with becoming bipedal. Sentinal behaviour of Meerkats, note the upright stance! BUT they drop onto all fours when they need to move!

    It is important to note that no other primate has adopted bipedalism as its primary mode of locomotion. There must have been different environmental factors which caused our ancestors to adopt what at first would be a very inconvenient mode of transport.