While modern Homo sapiens almost certainly descends —with the exception of a few genes contributed from Neandertals and Denisovans—from a group of ancestors who left Africa around 60,000 years ago and subsequently colonized the world, this was not the first hominin exodus from Africa. There are likely to have been several, 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.
That is documented in a new piece in the Guardian that announces the discovery, in a muddy estuary in Norfolk, of the oldest human footprints known from outside Africa. (The oldest footprints of any hominin known are, of course, the famous Laetoli footprints in Tanzania, dated about 3.6 million years old and probably made by Australopithecus afarensis. They’re described on pp. 201-202 of my book.)
Sadly, the Norfolk footprints were exposed by receding tides, and have now been washed away. But there’s a record, and a chance that further footprints will be found:
The prints were left by a small group of people heading south across the estuary at Happisburgh, through a landscape where mammoths, hippos and rhinoceros grazed. Scientists believe they were a group of adults and children, including one with a foot size the equivalent of a modern size 8 shoe, suggesting a man about 1.7 metres (5ft 7ins) tall.
The footprints are the first direct evidence of the earliest known humans in northern Europe, previously revealed only by the stone tools and animal bones they left scattered.
[JAC: I don't know what they mean by "direct" evidence; why aren't artifacts also "direct"? The Guardian seems to be flirting with the "historical" vs "real time" distinction raised by Ken Ham, seeing footprints as a "real-time" artifact.]
Within a fortnight of the discovery last May, the sea tides that had exposed the footprints destroyed them, on one of the fastest eroding parts of the East Anglian coast. However, Nick Ashton of the British Museum and other scientists managed to record them before they vanished, including taking casts of some of the best-preserved prints.
Here are photos of the footprints and a schematic of their layout, all from the Guardian article:
The footprints were dated from the geology, lying beneath later glacial deposits and the fossil remains of extinct animals, which Simon Parfitt, of the Natural History Museum, has identified as including mammoth, an extinct type of horse and an early form of vole.
On the day the small group walked across the wet mud, Britain was still joined to continental Europe. Their river valley, surrounded by coniferous forest, with saltmarsh and freshwater pools, offered a rich variety of food, including edible plants and seaweed, shellfish and animals for meat.
There’s a thrill in about seeing footprints of our close hominin relatives that you don’t get by simply seeing their bones or spearpoints. Footprints mean that we can imagine those ancients in action, walking around and looking for noms. The Laetolian footprints suggest two australopithecines walking side by side, with one set of prints larger than the other—perhaps a male/female couple. Moreover, the smaller prints are deeper on one foot than the other, suggesting that they might have come from a woman with a baby on her hip. Little did those early hominins know that their tracks, and their presence, would be marveled at millions of years later.
Now what the Norfolk researchers found (and what you see above) were footprint-sized ovals, but their spacing and size convinces me that I need to defer to the experts on this one. And the article adds the confirming information:
Photogrammetry, which combines photographs to create a 3D image, confirmed that they were indeed footprints, perhaps of five individuals. Some were clear enough to show heel, arch and toes – allowing an estimate of the height of the individuals at 0.9-1.7 metres.
These tracks are, by the way, about twice as old as the previous known footprints in Europe: the 345,000-year-old “Devil’s Footprints” from Campania in southwestern Italy, originally made in hot ash (by H. heidelbergensis), which hardened into stone. Here’s a video about those:
Those of you in the UK can see displays about these prints at a new exhibit opening next week at the Natural History Museum, Britain: One Million Years of the Human Story.
h/t: Grania, Steve