Fossils show two human ancestors were in same place at a similar time

About 1.5m years ago, a big-toothed cousin of prehistoric humans walked quickly along a lakeside in Kenya, footprints marking the muddy ground.

- Nicola Davis

But they were not our only ancestor on the scene: treading the same ground was the early human Homo erectus.

Researchers say an analysis of fossilised footprints discovered in deposits of the Turkana Basin, northern Kenya, suggests the marks were made by two different species on the human family tree who were in the same place within hours or days of each other.

While skeletal fossils have previously suggested these species may have coexisted, the timespans they can be dated to, and the size of the deposits they are found in, are too large to pin down interactions.

"This is the first direct snapshot of the two species together on the same immediate landscape," said Dr Kevin Hatala, the first author of the research from Chatham University in the US.