1.5 million-year-old footprints reveal our Homo erectus ancestors lived with a 2nd proto-human...

In a fossil first, researchers have announced the discovery of 1.5 million-year-old footprints that prove two different pre-human species coexisted in Kenya. The tracks hint that the species may have interacted, raising new questions about the behavior of our ancestors.

"I would expect the two species would have been aware of each other's existence on that landscape, and they probably would have recognized each other as being 'different,'" Kevin Hatala, a paleoanthropologist at Chatham University in Pennsylvania, told Live Science in an email.

Hatala led a team of researchers who analyzed the footprints, which were found at the site of Koobi Fora on the eastern shore of Lake Turkana in 2021. The scientists published their findings Thursday (Nov. 28) in the journal Science.