Steven Churchill, Associate Professor of Evolutionary Anthropology at Duke University in America, said the skeleton's rib injury had been a subject of intense speculation among anthropologists and paleontologists ever since he was discovered.

"Some said it was interpersonal violence. Others said it could have been an accident," he said.

"Did it involve only Neanderthals? Now we, for the first time, have brought some experimental evidence to bear on these questions."

He said the Neanderthals' thrust spear produced a much more untidy wound than a projectile spear used by Homo Sapiens, which left a solitary rib puncture.

"When a pig carcass was stabbed with a thrust spear its ribs were busted to hell. The high kinetic energy had caused a lot of damage in the area," he said.

"However, whatever created that puncture was carrying fairly low kinetic energy at a low momentum. That's consistent with a spear-thrower delivered spear.