SAD LOVE QUOTES: This one's got legs... Humans walked upright far earlier than previously thought

Wednesday, July 20, 2011

This one's got legs... Humans walked upright far earlier than previously thought

Human-like footprints found dating back 3.7million years

Last updated at 3:43 AM on 20th July 2011

Ancient ancestors: The footprints are thought to have been left by the Australopithecus afarensis, a primitive early human

Humans were on their feet in far more ancient times than previously thought, research suggests.

Until now it was believed that the ability to walk upright on two legs evolved around 1.9million years ago.

But scientists have discovered human-like footprints dating back almost 3.7million years.

The 11 prints, preserved in rock sediment in Laetoli, Tanzania, display a gait more like that of modern humans than the awkward upright walking posture adopted by chimpanzees, orang-utans and gorillas.

Previous finds have generally been of single prints, making it difficult to distinguish between genuine and artificial features.

The footprints are thought to have been left by Australopithecus afarensis, a primitive early human that may be a direct ancestor of everyone living today.

Scientists compared their analysis of the prints with data from footprint studies of modern humans and apes.

Computer simulations were also used to predict what kind of footprints would have been formed by different gaits.

Lead researcher Professor Robin Crompton said: 'It was previously thought that Australopithecus afarensis walked in a crouched posture, and on the side of the foot, pushing off the ground with the middle part of the foot, as today's great apes do.

'We found, however, that the Laetoli prints represented a type of bipedal walking that was fully upright and driven by the front of the foot, particularly the big toe, much like humans today, and quite different to bipedal walking of chimpanzees and other apes.

The Australopithecus afarensis footprints are thought to date back 3.7million years

'Quite remarkably, we found that some healthy humans produce footprints that are more like those of other apes than the Laetoli prints.

'The foot function represented by the prints is therefore most likely to be similar to patterns seen in modern humans. This is important because the development of the features of human foot function helped our ancestors to expand further out of Africa.'

The research suggests the ability to walk in a modern human way evolved almost four million years ago in a species thought to have spent at least some of the time in trees.