Some of the earliest stone tools ever discovered by archaeologists were discovered in Kenya and date back to 2.9 million years.
They claim the finding shows that early humans from several branches of the genus Homo, as opposed to Homo sapiens alone, as had been previously believed, used tools.
According to researchers, two enormous fossilised teeth discovered at the site in Kenya belonged to Paranthropus, an extinct relative of humans.
The investigation team discovered evidence that the instruments were used to slaughter hippos and crush plant components including tubers and berries.
