From British daily The Independent:
Scientists working in west Africa have found stones used by chimpanzees as hammers more than 4,300 years ago in a discovery that further undermines the idea that tool use is unique to human culture.
Wild chimpanzees – man’s closest living relative – have been documented as using various tools throughout Africa but this is the first time evidence has emerged of ancient culture among chimps.
Scientists believe the discovery suggests that use of tools probably evolved in the common ancestor of humans and chimps and has been passed down the generations as culturally acquired behaviour, according to Julio Mercader of the University of Calgary in Canada.
“We used to think that culture and, above anything else, technology was the exclusive domain of humans, but this is not the case,” he said
There are three possible explanations for tool use among chimps.
The first is that they developed it by imitating forest-dwelling humans, the second is that they developed it independently of humans and the third is that they inherited the practice from the same common ancestor that chimps share with humans.
Chimpanzees making spears: here.
Chimpanzee-human split four million years ago: here.
Lion eating chimpanzees: here.