The skeleton of a human ever discovered was found, in 1823, in southern Wales, ceremonially buried under six inches of soil in a limestone cave facing the sea. William Buckland, the Oxford geologist who unearthed it, didn’t know what he had come upon. Buckland had been busy exploring caves in England and Germany, noting the loamy soils and the animal bones they contained as indications of “the last great convulsion that has affected our planet’’—the Biblical flood, he meant. In Goat’s Hole Cave, in Wales, he found the bones of a hyena, a bear, a rhinoceros, an elephant (actually a mastodon), deer, rats, and birds, and roughly half of a human skeleton, which had been stained with red ochre and laid to rest with periwinkle shells and an assortment of ivory rods and broken armlets. At first, Buckland thought it was a man—perhaps a taxman killed by smugglers—but then he decided that it was a woman, maybe a fortune-teller, or a witch, or a prostitute from the days of the Roman occupation. He called her the Red Lady of Paviland. Whoever she’d been, Buckland wrote, she was “clearly postdiluvian,” a relatively recent deposit.
Only much later was the Lady revealed to be a man after all, and, in 2009, after decades of effort, scientists determined that the skeleton is thirty-three thousand years old—the oldest human remains ever found in Britain. By now, of course, we know that the history of our species is far more ancient, although the evolutionary tree keeps changing shape and sprouting limbs. For a while, it was thought that modern humans, who were present in Europe by at least forty thousand years ago, descended from Neanderthals, which have been known and recognized as separate creatures since the nineteenth century. In fact, though, Neanderthals were our cousins; we shared a common ancestor, and our populations overlapped until about forty thousand years ago, when, probably, we drove them extinct. Starting in the nineteen-sixties, a series of spectacular fossil discoveries made it clear that Homo sapiens arose in Africa. We didn’t shuffle off the continent until a hundred and twenty thousand years ago or less, but it turns out that earlier hominins, Homo erectus, had been spilling out of there for ages already, making stone tools and, eventually, fires.
The further back we place ourselves in the Paleolithic, the busier the place seems to get—and the less unique we appear to have been. Today, the story got even richer. In a paper in the journal Nature, an international team of researchers announced that they have pushed back the date of the earliest human remains to three hundred thousand years ago. And the specimens in question were found not in East Africa, which has become synonymous with a sort of paleoanthropological Garden of Eden, but clear on the other side of the continent—and the Sahara—in Morocco. “We’re not claiming that Morocco is the cradle of modern humankind,” the lead author, Jean-Jacques Hublin, of the Max Planck Institute for Evolutionary Anthropology, said at a press conference yesterday. Rather, he added, our emergence as a species was pan-African. “There is no Garden of Eden in Africa—or if there is, it’s Africa,” Hublin said. “The Garden of Eden is the size of Africa.”
The site in question, Jebel Irhoud, is part of a network of caves that lies about sixty miles west of Marrakesh. In 1960, a mining operation unearthed an array of animal and human bones there, including a nearly complete hominin skull. But the remains were a puzzle—they were initially dated at forty thousand years old and thought to be Neanderthal, not human. Maybe this was a far-flung outpost of the European populations, the occupant a Neanderthal Robinson Crusoe. In 1968, a child’s jawbone was found; the teeth suggested that it belonged to Homo sapiens, and improved dating techniques put it at a hundred and sixty thousand years old. Maybe this was a human site after all, a backwater branch of those early Homo sapiens in East Africa. In 2004, Hublin and his colleagues began to excavate in earnest, and brought the total number of hominin bones to twenty-two. All came from the same stratigraphic layer. Once the researchers had analyzed them, Hublin said, “the dates were a big wow.”
In 1823, when William Buckland discovered the Red Lady of Paviland, part of what misled him about its age—in addition to his own inability to envisage “antediluvian” humans—was its appearance. Morphologically, a thirty-thousand-year-old specimen of Homo sapiens is all but identical to one walking around today. A persistent question among paleoanthropologists is how far back this similarity goes. Modern humans are distinguishable from, say, Neanderthals by our flatter, more delicate faces and our more globular crania, which encase larger and more complex brains. How closely did the earliest humans resemble us in this regard? How quickly did we come to look the way we do?
To approach an answer, Hublin’s team used a tomography scanner to examine the Irhoud fossils and compare them with other examples from around the world. This revealed “a series of features that are basically indistinguishable from those in modern humans,” Hublin said. The face was remarkably similar, short and retracted below the brow. “It’s the face of people you could cross in the street today,” he said. The skull, however, was flatter and more elongated—that’s the feature that has changed most since our days in Irhoud, likely in response to a series of genetic mutations that are known to have improved our brain organization, connectivity, and development. “It was face first, brain after,” Hublin said. John Fleagle, an anthropologist at Stony Brook University, told me, “If you take a human skull and enumerate fifteen things that make it ‘human,’ this thing”—the three-hundred-thousand-year-old Homo sapiens—“has five or six of them. It doesn’t have the full shebang.”
But, even with that flatter skull, a human from the early days wouldn’t stand out in a crowd, Hublin told me: “In the street you see a lot of different things, eh?” (He added, however, that their “robust” musculature “probably would be the most frightening feature.”) The scientific literature sometimes draws a distinction between recent modern humans and early modern humans—R.M.H. and E.M.H.—but Hublin cautioned against thinking of these as actual separate categories. We’re all one species, very slowly evolving. “There is no gap, no break point, in the lineage leading from Irhoud to us,” he said.
As the number of fossil Homo sapiens continues to grow, and as their images proliferate in the literature alongside those of Homo neanderthalensis, Homo heidelbergensis, Homo naledi, and the other members of the budding genus, we start to look less human and more like every other animal in the animal kingdom. The one trait that we think of as most distinctively human, beyond our fine cheekbones and impressive cerebellum, is the stuff we make, our culture—paintings, beads, figurines, and everything that followed. But this is all relatively recent—within the past hundred thousand years or so—and not unique to us. The Neanderthals used pigments, collected bird feathers, and buried objects with their dead; in March, scientists revealed a raven bone that had been aesthetically carved by a Neanderthal, roughly forty thousand years ago.
In any case, there was a long period—two hundred thousand years, it now appears—during which “human culture” involved only stone tools, as with pretty much every other Paleolithic hominin. Were we like them, or were they like us? We were all subject to the same pressures, and we navigated the same environmental shifts. Africa has seen enormous fluctuations in climate in the past few hundred thousand years, Hublin observed. More than once, the northeast limit of the summer monsoon has moved north, essentially replacing the Sahara with grasslands rich in the kind of wildlife—gazelle, wildebeest, zebra, big cats—whose remains were found in the Irhoud cave. “That is absolutely gigantic,” Hublin said. “The Sahara is the size of the United States, an area that stretches from Tanzania to Morocco. And it happened again and again. It blows our minds.”
Such episodes would have connected previously isolated regions of Africa, enabling early humans to occasionally disperse across the continent, perhaps in pursuit of migratory game. There would have been relations, a regular exchange of genes, a diversifying, pan-African people. The Paleolithic era starts to sound almost multicultural. Hublin noted that a green-Sahara period occurred around three hundred thousand years ago, just prior to the date of the Irhoud site. The researchers speculate that Irhoud may have been a hunting camp, a pit stop on a longer journey; it’s clear that the flint in the tools found there came from miles away. It’s also clear that paleoanthropologists will need to expand their search beyond East Africa, which, it now seems, may be considered the cradle of humankind mostly because it’s so rich in specimens. “There’s a lot of rocks of the right age and a lot of bones to find,” Fleagle told me. Have we been looking for our keys under the street lamp, because that’s where the light is?
Hublin emphasized that identifying the oldest known human remains doesn’t mean they were the first—far from it. Phylogenetic studies indicate that Homo sapiens and Neanderthals last shared a common ancestor, Homo heidelbergensis, about six hundred and fifty thousand years ago, so our species won’t turn out to be older than that. Still, he said, “what happened in Africa between six hundred thousand and four hundred thousand years ago is basically unknown.”
(Originally Published at The New Yorker, click here for more)
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