Scientists Say Early Hominids Walked on Their Knuckles

When humanity’s early ancestors first jumped down from the trees, they did not walk fully upright but probably scooted along on their knuckles much like chimpanzees and gorillas do today, scientists said Wednesday. A chance discovery made by looking at a cast of the bones of “Lucy,” the most famous fossil remains of the early hominid known scientifically as Australopithecus afarensis, shows that her wrist is stiff, like a chimpanzee’s, reported Brian Richmond and David Strait of George Washington University in Washington, D.C.

This suggests that her ancestors--and ours--walked on their knuckles. The stiff wrist limits the flexibility of the hand but makes the forearm strong enough to carry the weight of a heavy primate, Richmond said.

“We have found evidence in the wrist joint that sheds new light on arguably the most fundamental adaptation in humans . . . which is why did humans start walking upright?” Richmond said.

“Walking upright is the hallmark of humanity. It is the feature that defines all of our ancestors to the exclusion of our ape relatives.”