At more than 800,000 years old, the impressions, recently discovered in England, are the most ancient evidence of human life in northern Europe, and the earliest examples of human footprints outside of Africa.
Last year, archaeologists happened upon dozens of shallow hollows and depressions on the shores of Happisburgh, along the Norfolk Coast in the east of England. The depressions had been washed out by a storm and exposed by the tide. The researchers immediately took notice of their size, shape and position. Archaeologist Nick Ashton, of the British Museum, describes the discovery in a blog entry:
We found them by pure chance in May last year. We were about to start a geophysics survey on the foreshore, when an old-time friend and colleague, Martin Bates from Trinity St David's University, pointed out the unusual surface. The site lies beneath the beach sand in sediments that actually underlie the cliffs. The cliffs are made up of soft sands and clays, which have been eroding at an alarming rate over the last ten years, and even more so during the latest winter storms. As the cliffs erode they reveal these even earlier sediments at their base, which are there for a short time before the sea washes them away.
"We wondered whether these are, in fact, footprints," said Simon Parfitt, an archaeologist at University College London. "Animal footprints and possibly even human footprints."
What the researchers needed to do, Parfitt explains in the above video, which recounts the discovery, was uncover the impressions and photograph them from various angles so as to create 3D reconstructions of the site. One year later and the researchers have done exactly that – and what they've found is one of the most remarkable discoveries ever made on British shores.
British Museum archaeologist Nick Ashton said the find — announced Friday and published in the journal PLOS ONE — was "a tangible link to our earliest human relatives."
Preserved in layers of silt and sand for millennia before being exposed by the tide last year, the prints give a vivid glimpse of some of our most ancient ancestors. They are from a group, including at least two children and one adult male. They could be a family foraging on the banks of a river scientists think may be the ancient Thames, beside grasslands where bison, mammoth, hippos and rhinoceros roamed.
The researchers said the humans who left the footprints may have been related to Homo antecessor, or "pioneer man," whose fossilized remains have been found in Spain. That species died out about 800,000 years ago.
Ashton said the footprints are between 800,000 — "as a conservative estimate" — and 1 million years old, at least 100,000 years older than the previous earliest evidence of human habitation in Britain.
Footprints believed to have been left by anatomically modern humans have previously been discovered in Africa, and date to as early as 1.5 million years ago.
"I imagine that there will be plenty of skeptics out there, as were we initially, but the more we eliminated the other possibilities, the more convinced we became," writes Ashton. "The sediments are hard and compacted – you can jump on them today and leave little impression. And there are no erosional processes that leave those sort of hollows."
The researchers' findings are slated to appear in a forthcoming issue of PLOS ONE. This link won't be active until the paper goes online; until then, I recommend heading to the BBC for Pallab Ghosh's excellent write-up, or the British Museum for Ashton's blog entry.