Walking upright is something we might take for granted nowadays. But it has in fact been one of the greatest advances in human evolution. Now a new fossil find confirms that more than 3 million years ago a key ancestor of humans could walk upright, just as we do.

Palaeo-scientists already knew that Lucy, the most famous of our ancestor Australopithecus afarensis, spent some of her time standing tall. But now a 3.2 million year-old bone found in Hadar, Ethiopia confirms that she could in fact do it consistently.

For the first time scientists found a foot bone that confirms that the tiny, human-like species had arched feet, like humans. This arch has two functions in walking, one is to propel the body forward and the other is to act as a shock absorber. Two functions that the feet of our modern ape cousins do not have and nor need, since these animals need feet for gripping as they traverse the tree tops.

The evidence sets Australopithecus afarensis as our first known ancestor to walk upright. But did they move as we do or was it more like a waddling gait?

© Jorn van Dooren | www.bitsofscience.org