Cape forebears were sharp to technology

Back 500000 years ago, an arms race was playing out in what has become Northern Cape.

Here scientists have found the earliest known examples of stone-tipped spears, a technology more advanced than wooden spears.

But the question is why our ancestors chose stone over wood. The answer came from buckets of gelatin, used to simulate flesh.

A group of academics went CSI and conducted a ballistics test to see which weapon was better.

Their results were published in the latest issue of the Plos One academic journal.

The stone-tipped spears were copied from those found at Kathu Pan, in Northern Cape. They are dated to 500000 years old.

Each spear, explained Benjamin Schoville, co-author of the paper, was fired into a bucket of gelatin with a crossbow.

"We had to use the same force each time and record the amount of penetration," said Schoville, an archaeologist at the Institute of Human Origins at Arizona State University.

What they found was that, while stone-tipped spears didn't penetrate as deeply as untipped spears, they caused a much larger inner-wound cavity.

"It is like a hollow-point bullet, which creates a lot more tissue damage," Schoville explained.