Anthropologists studying chimpanzees found the great apes, who usually walk on all fours, walk upright and free their hands for carrying when they need to grab more hard-to-find resources in one go, in the face of competition.This has always been part of the bipedality model, that early hominins exploited the forest/fringe environment where they could get what they needed from the trees and from the savannas. The fact that Ardipithecus ramidus demonstrated bipedality in a forested environment sort of threw cold water on the more conservative of those models but it is also clear that even the level of bipedality continued to evolve over time and that, by the time later australopithecines had completely human, obligate bipedal locomotion, these hominins were living in the open and competing for those resources. It was at this point that our brains began to expand as well.
The team from the University of Cambridge and Kyoto University in Japan believe the benefit of “first come, first served” and getting a bigger share of scarce food supplies could, over a long period of time, have led some of our earliest “hominin” ancestors to evolve into “bipedal” primates walking on two legs permanently instead of four.
Now playing: Bill Bruford's Earthworks - Cloud Cuckoo Land