Happisburgh, England — on the coast of the North Sea — has been the site of several amazing archaeological discoveries in recent years, all of them pointing to human ancestors traveling much farther north, much earlier, than had previously been believed. The site is back in the news now, because of a paper published in the journal PLOS ONE documenting a series of footprints that were discovered when they were exposed by a low tide last May. The footprints were made in sediments that date to 800,000 years ago, making them the oldest footprints ever found outside of Africa.
Back in 2010, researchers discovered flint tools, dating to roughly the same time frame and found on the same beach.
The footprints are particularly interesting not just because they're, well, footprints, but also because they were destroyed shortly after they were discovered. A low tide exposed the ancient sediment the footprints had been laid down in and then, within two weeks, storms and the sea wore the footprints away. The PLOS ONE paper is based on photographs, video, and the 3D scans taken of the footprints while they still existed. Although there were 49 footprints, scientists only had time to really heavily document 12 of them. It's an example of excellent, difficult, time-sensitive archaeology.
It's also a great example of why "Out of Africa" theory should be understood in a different way than it generally, popularly is, writes Jerry Coyne at Why Evolution Is True. By now, pretty much everybody knows the basic Out of Africa idea — human ancestors first evolved on the African continent and then traveled to other places from there. What gets easily forgotten, though, is that our ancestors left Africa more than once. As Coyne explains, genetic evidence suggests that we living humans are related to a group that left Africa 60,000 years ago. But, more broadly, hominins were traveling long before that — they just aren't as closely related to us.'
There are likely to have been several [exoduses], beginning with the spread of H. erectus 1.8 million years ago and continuing through the next million years or so with other relatives, including the ancestors of the Neandertals. So when you hear the “out of Africa” hypothesis associated with a relatively recent date, remember that our relatives (some of whom contributed genes to the modern human genome) left Africa much earlier.
In this case, the hominins — nobody knows exactly what species, though, based on contemporaneous fossil finds in Spain, researchers suspect it was Homo antecessor — could have walked to the English coast from what is now mainland Europe. At the time, there was a land bridge between two, exposed because more of the world's water was then locked up in an ice age. The downside is that the same ice age would have made what is now England a not particularly hospitable environment. Given human nature, it's probably not surprising that humans were traveling farther than we'd previously had evidence to support. But, given the cold, it's also not terribly surprising that there's a lot more evidence of H. antecessor habitation in southern Europe.
Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.