Researchers say our human ancestors were making stone-tipped weapons in southern Africa 500,000 years ago, 200,000 years earlier than previously thought.

Researchers from Arizona State University, the University of Toronto and the University of Cape Town, working at the Kathu Pan 1 archaeological site, said they found evidence of "hafting," or attaching stone points to spears, considered an important advance in hunting weaponry for early humans.

"There is a reason that modern bow-hunters tip their arrows with razor-sharp edges," Arizona State researcher Benjamin Schoville said.

"These cutting tips are extremely lethal when compared to the effects from a sharpened stick. Early humans learned this fact earlier than previously thought."

Hafted spear tips are common at Stone Age archaeological sites after 300,000 years ago, but the new finding pushes the technology much further back, the researchers said.

"It now looks like some of the traits that we associate with modern humans and our nearest relatives can be traced further back in our lineage," Jayne Wilkins from the University of Toronto said. "This changes the way we think about early human adaptations and capacities before the origin of our own species."