Muddy Footprints Suggest Early Humans Were Neighbours in Kenya

Thomas Roach (mayor)member of the New York City Council

The Paranthropus tracks lack this tall arch and indicate a more flat-footed walk. Additionally, the Paranthropus tracks show a big toe that is a bit more diverged from the other toes and more mobile. Both of these aspects are more similar to the way a chimpanzee walks, although clearly distinct and intermediate between chimpanzee and human footprints,

Roach said

Thomas Roach (mayor)member of the New York City Council

The fact that we consistently see two species of hominins in these landscapes, despite the presence of dangerous animals such as hippos and crocodiles, suggests that these environments were important enough to our ancestors to be worth the risk of visiting,

Roach said

It is possible that they competed directly, but also possible that they were not in direct competition and both had access to the resources that they needed on this shared landscape,

said paleoanthropologist and study lead author Kevin Hatala of Chatham University in Pittsburgh

The tracks we attribute to Homo erectus have a very modern human-like shape with a tall arch of sediment in the middle of the track that indicates a stiff foot and a walking gait that includes pushing off the toes,

said Harvard University evolutionary biologist and study co-author Neil Roach

The fossil footprints provide us a clear picture of that instant in time, 1.5 million years ago. The different human ancestors may well have passed by each other, wading in the shallow water, possibly hunting and gathering,

said paleoanthropologist Louise Leakey, director of the Koobi Fora Research Project and co-author of the study published on Thursday in the journal Science

Paranthropus boisei consumed low-quality forage that likely required repetitive chewing. Homo erectus was likely to be omnivorous, using tools to butcher carcasses, and also had meat in its diet,

Leakey said

With these kinds of data, we can see how living individuals, millions of years ago, were moving around their environments and potentially interacting with each other, or even with other animals

he added

I would expect the two species would have been aware of each other’s existence on that landscape, and they probably would have recognised each other as being ‘different’,

said Hatala

There are aspects of their big toe anatomy, in particular, that seem consistent with the patterns that we see in the footprints,

said Hatala

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

It’s wonderful that these early human relatives can now be placed directly in a lakeside landscape, walking and wading on wet surfaces, and probably feeding on the plant and animal resources there,

he said

Their presence on the same surface, made closely together in time, places the two species at the lake margin, using the same habitat,

Feibel said

Fossil footprints are exciting because they provide vivid snapshots that bring our fossil relatives to life,

Kevin Hatala, the study's first author and an associate professor of biology at Chatham University in Pittsburgh, said in a statement

It hints at aspects of paleobiology that are difficult to reconstruct but crucial these and other hominin species,

anthropologist William Harcourt-Smith of Lehman College—who was not involved in the study—wrote in an accompanying Perspective article

This [study] proves beyond any question that not only one, but two different hominins were walking on the same surface, literally within hours of each other,

paper author and geologist Craig Feibel of Rutgers University in New Jersey said in a statement

We think these footprints were made in the mud in this lake shore environment. Something happened to bring sediment in over top of it. It could have been a small flood or a rise in the water level that carried in sediments and buried the footprints soon after they were formed,

Hatala said

Lots of people have thought they are as good of a candidate as there is to be a direct ancestor of ours,

Hatala said

The sediment protected them and prevented them from cracking and allowed them to be entered into the geologic record,

Hatala said

They’re thought to have gone extinct not too long after this, within the next few hundred thousand years,

Hatala said, referring to the time of the footprints

They have to carefully rebury it with sediment that won’t damage the footprints so erosion won’t occur,

he said