Washington: The necessity of carrying more of scarce, high quality resources may have prompted human beings to adapt to walking upright millions of years ago, a study reveals. The team from the US, England, Japan and Portugal investigated the behaviour of modern-day chimps to learn what prompted a large ape, which resembled the six-million-year-old ancestor we shared with living chimps, to walk on two legs.
“These chimpanzees provide a model of the ecological conditions under which our earliest ancestors might have begun walking on two legs,” said Brian Richmond, of the George Washington University, study co-author and associate professor of anthropology.
“Something as simple as carrying – an activity we engage in every day – may have, under the right conditions, led to upright walking and set our ancestors on a path apart from other apes that ultimately led to the origin of our kind," said Richmond, the journal Current Biology reported. The research findings suggest that chimpanzees switch to moving on two limbs instead of four in situations where they need to monopolize a resource, usually because it may not occur in plentiful supply in their habitat, making it hard for them to predict when they will see it again, according to a university statement.
Standing on two legs allows them to carry much more at one time because it frees up their hands. Over time, intense bursts of two-legged activity may have led to anatomical changes that in turn became the subject of natural selection where competition for food or other resources was strong.