Walking upright uses less energy
From Times Staff and Wire Reports
Why did humans evolve to walk upright? It turns out that humans walking on two legs use only a quarter of the energy that chimpanzees use while knuckle-walking on four limbs, researchers reported this week in the Proceedings of the National Academy of Sciences.
The chimps, on average, also used as much energy using two legs as they did when they used all four limbs. University of Arizona researchers measured the energy consumption of humans and of chimps walking on four legs or two on a treadmill. Some chimps used less energy walking upright, and the researchers speculated that modern humans evolved from ancestors with the same trait because it freed energy for other purposes.
