the-BA : Did Lucy run?

By Rozelle Kane

New evidence suggests that our earliest ancestors could walk but not run. Dr Bill Sellers of the University of Manchester has made "dead men walk" by adding springs to computer models of ancient skeletons.

Dr Sellers told the BA Festival of Science that ability to run – and therefore chase prey - may be one of the earliest features of the human split from our closest living relatives, chimpanzees.

The extraordinary extrapolation – from bones to moving models – comes from exquisitely precise statistical analysis from teams of scientists at the Universities of Manchester, Cambridge and Vienna.

New computer models bring together millions of individual points of measurement from the bones' surfaces to "flesh out" the image. Dr Sellers has been using computer modelling in order to bring the few full skeletons of hominids (early humans) to life. Well, to movement.

It is suggested that between 3.5 and 2 million years ago we gained the ability to run. This development precedes a key aspect of human evolution: growth of the brain. The significant enlargement of the brain is likely to have occurred 2 million years after running!

In the case of fractured skull relics for example, it is now possible reliably to fill in the missing gaps. Whereas earlier anthropologists used "intuition" and "words", modern scientists are able to use "facts" and "numbers", said Professor Gerhard Weber of the Pedagogical University in Freiburg.

Dr Sellers has taken this technology one step further by comparing the likely movement of two ancient skeletons. He compares the skeleton with and without "spring".

Amazingly, the two locomotions look very different. Running without springs would be virtually impossible. It also takes almost double the amount of energy to go only half the speed of a model with springs.

This spring in our step is something that we all take for granted, but haven't always had. In physiological terms, it comes from our Achilles tendon, a piece of stretchy tissue that attaches our calf muscle to our ankle bone.

The Achilles tendon is like a very tight elastic band. When stretched, it stores energy, ready to ping, and catapult us into movement. This allows humans to leap and therefore run.

The next step (no pun intended) is to search for evidence for the Achilles tendon in all available skeletons. Scientists could then build a timeline for the onset of running. As ever, communication is crucial, as many of the skeletons in held in Africa and not readily available.

"We’re pointing out things to look for," said Dr Sellers. Another place to look is fossils of our nearest relatives, to find out when the developed an Achilles tendon.

The new technology also allows analysis of the size and pressures on the skull. There is some evidence that the temporal lobe was smaller in hominids, which has important implications for speech production, perceptual processing and many other functions.

Read more news coverage at BBC News, the Guardian and the Times. Watch the animation here.