NMNH - Fossil Footprint

Two of the 1.5 million-year-old footprints preserved at the site. The research team attributes the one on the left to Paranthropus boisei, a member of an extinct side branch of human relatives, and the one on the right to Homo erectus, which could be a direct ancestor to humans.

In a paper published today, Nov. 28, in the journal Science, an international team of researchers from the U.S., Kenya and the UK provide the first direct evidence of two different ancient human relatives, H. erectus and P. boisei, simultaneously occupying the same immediate landscape. The research team analyzed a newly discovered fossil footprint site in northern Kenya that records two different kinds of ancient footprints left along the margins of a lake around 1.5 million years ago. These fossil footprints reflect different patterns of anatomy and locomotion, providing the first direct documentation that H. erectus and P. boisei occupied the same environment and could have interacted with each other.