Almost human: who were the primitive Homo sapiens who lived
The first modern humans appeared between 200,000 and 350,000 years ago, based on estimates made from our DNA. However, no bones of modern Homo sapiens are known from this time, or for tens of thousands of years afterwards. Instead, we have fossils of primitive-looking Homo sapiens- people with big brow ridges, low skulls, and massive jaws like Neanderthals. If the estimated time of human origins based on DNA is correct, these people couldn’t have been our direct ancestors. Instead, they were contemporaries of the first modern humans, a primitive and extinct side branch of our species. So who were they- and what happened to them?
The fossil record tends to be sparse when it comes to human beings, but for the earliest modern Homo sapiens, we have no fossils at all. Divergence time estimates- where we compare DNA sequences, then use models of evolution to tell how much time passed to evolve these differences- tell us fully modern Homo sapiens appeared somewhere between 200,000 years ago and 350,000 years ago.
Modern-looking human fossils from this time period are absent, but this is hardly surprising. The high genetic diversity seen in southern Africa suggests we’ve spent a long time there, and we probably evolved near what’s now the Okovango delta, in Botswana. That pattern also fits the high language diversity in the area. If so, we were initially confined to a small area in Southern Africa, a place without good human fossils. Given this, we’d expect modern human fossils to appear much later in the fossil record, only once we spread out of this ancestral homeland and started ending up in caves and river deposits elsewhere.
But while we don’t have truly modern humans from this time, we do have Homo sapiens fossils from this time period- they just aren’t modern. They include the Jebel Irhoud skulls from Morocco, the Omo skulls in Kenya, the Herto people in Kenya, the Eyasi skulls in Tanzania, the Florisbad skull in the Cape of South Africa, the Skhul and Qazfeh people in Israel, and the Apidema Cave skull in Greece. While these fossils have been called “anatomically modern Homo sapiens”, modernity is a relative concept, and in my opinion “anatomically modern” seems a stretch. True, these people may be “anatomically modern” compared to Neanderthals or Homo erectus, but I’d argue it’s a misleading word- they’re not very modern compared to us.
These people had lots of primitive features. The most obvious is the massive brow ridge above the eyes, a primitive feature shared with species like Neanderthals, Homo erectus, and Homo rhodesiensis. The skulls also lie outside or at the edge of the range of variation seen in modern Homo sapiens in various measurements; in side view, the skull is more elongated and egg-shaped, whereas modern Homo sapiens has a more spherical, globe-shaped skull. They had a big muzzle, and a huge nose. As we’ll see, these changes probably aren’t just superficial. One way they didn’t differ from us was brain size- their brains were as large as ours, as in the Neanderthals.
These various peoples- Jebel Irhoud, Omo, Herto, Eyasi, Florisbad- represented a distinct lineage or subspecies of Homo sapiens. Perhaps more likely, given their wide geographic spread, they represented multiple subspecies, not particularly closely related to one another, and some, probably the southern ones, closer related to us.
Because these people were anatomically more primitive, we might assume they were directly ancestral to us. But as with the Neanderthals, they couldn’t have been our direct ancestors, because they existed at the same time we did, not before (again, if we trust the DNA evidence). The Jebel Irhoud people date to around 300,000 years ago, about the time we evolved. The Apidema skull dates to > 210,000 years ago, Omo people date to 195,000 years ago, the Herto people to <164,000 years ago, the Eyasi people to >130,000 years ago, and Qazfeh/Skhul to around 100,000 years ago. In fact, these archaic Homo sapiens probably survived very, very late. The persistence of primitive Middle Stone Age tools in Tanzania suggest the Eyasi people survived late to at least 64,000 years ago. Modern human tools only appear in Lake Eyasi between 64,000 and 57,000 years ago, possibly representing the incursion of todays Hadzabe, Sandawe, or related African tribes. That suggests these archaic Homo sapiens survived in Africa thousands of years after we’d spread out of Africa into Asia, or even Australia, where modern humans showed up over 65,000 years ago. So rather than our ancestors, these archaic people in Africa and elsewhere were our contemporaries. Since they lived the same hunting-and-gathering lifestyle we did, they were our competitors. And, probably not coincidentally, as we spread through Africa they disappeared.
So if they weren’t modern Homo sapiens, and they weren’t the ancestors of modern Homo sapiens, who were they?
These people appear to represent an early, archaic form of Homo sapiens, who became widespread in Africa around 300,000 years ago, but quite likely earlier. They seem to have displaced earlier human species, to a degree; they replace more primitive Homo erectus-like forms, although they likely overlapped in time with the more advanced Homo rhodesiensis and the more primitive Homo naledi. These archaic sapiens appear to spread as far as North Africa, and then briefly moved into Israel and even southern Europe, in Greece, before being beaten back by Neanderthals around 170,000 years ago in Greece, and 60,000 years ago in Israel.
Primitive Homo sapiens raise a lot of the same questions that Neanderthals do. They were clearly very close to modern humans, but just how human were they? It’s reasonable to guess they were at least as human as Neanderthals. Like Neanderthals and modern hunter-gatherers like Bushmen and Hadzabe, they were probably hunters who targeted big game, taking small game when they could, using javelins and throwing sticks. Women probably gathered roots with digging sticks. They likely used fire, probably made necklaces, abstract art, and buried their dead- all things both modern humans and Neanderthals do.
And almost certainly they had a relatively complex language, approaching ours in sophistication. While language obviously doesn’t fossilize, it’s an extremely complex adaptation, and it’s unlikely such a complex feature- the ability to produce distinct phonemes linked into words, then linked together by grammar into complex sentences- would have suddenly evolved in the few hundred thousand years of evolution between us and them, without any sort of precursor behavior. Instead, just like the shapes of our bones, language probably evolved incrementally, over millions of years- so they probably had something very like modern human language.
In technology, archaic Homo sapiens’ tools were sophisticated, but no more so than in Neanderthals as far as we can tell; they relied on similar large hand-axes, and used the same flintknapping technique, called the Levallois technique, which produces large blades from prepared cores, that Neanderthals did. And when they met the Neanderthals, they initially had some success pushing into Israel and then southern Europe, but were later pushed back by the Neanderthals. That suggests in terms of culture, technology and intelligence, these primitive sapiens were more or less evenly matched against Neanderthals. And like Neanderthals, and unlike modern Homo sapiens, their appearance apparently isn’t linked to large mammal extinctions- they weren’t as good at hunting as we were. Neither were they able to displace all the other humans- Neanderthals, Denisovans, Homo rhodesiensis- the way modern Homo sapiens did.
Another way these primitive Homo sapiens parallel the Neanderthals is that they shared the Neanderthals’ fate- they were wiped out when we appeared. Modern humans slowly began to spread through Africa soon after we first evolved. Wherever we went, these archaic humans were displaced, and modern humans and their tools replace them. This took a while, as with Neanderthals; it was a long, slow fight, a war of attrition and not blitzkrieg. As we’ve seen, in northern Tanzania, modern human tools don’t appear until around 60,000 years ago, and humans didn’t spread into northern Africa until even more recently. It’s likely that we intermarried, as we did with Neanderthals, Denisovans, and probably H. rhodesiensis- humans seem to have a thing for cross-species mating. However, if we did, we haven’t yet found their DNA in us.
It’s noteworthy that everywhere modern humans went, we displaced them, never the reverse- as with Neanderthals. Was this because of chance, or somehow due to modern humans superiority? In conflicts between civilizations like the Greeks and Romans, the fate of empires is decided by a few, large battles. That means chance events- a sudden panic in the ranks, an elephant going out of control- can turn the tide of battle, and the fact that western Civilization is built on a Roman foundation and not a Greek one could just be chance- the results of these handful of battles aren’t statistically significant to allow us say the Romans were superior to the Greeks.
But it’s unlikely that chance can explain why modern Homo sapiens prevailed against primitive members of the species. Conflicts between these ancient hunter-gatherers took place over tens of thousands of years, countless small skirmishes, raids and minor battles between bands and tribes. Homo sapiens slowly but inevitably gained ground, consistently winning territory more often than we lost, over thousands of years. That implies our success wasn’t just dumb luck or a fluke; here the results clearly rise to the level of statistical significance. Something (something!) set us apart from them, just as something set us apart from Neanderthals. But what was it?
If we consistently outcompeted them, why? Was it language, ability with tools, abstract thought, creativity, social structures? Or maybe all of these things together- but what could drive that?
The clue may be in modern humans’ weird skull shapes. The anatomical differences between us and archaic sapiens probably aren’t just superficial or decorative. For one, a different skull shape implies a different brain shape, possibly with different regions enlarged or reduced relative to the modern human condition. But what’s truly striking is that differences between us and them- globular skulls, reduced brow ridges- imply a different pattern of development. These same differences are seen not only between modern and primitive Homo sapiens, but also between juveniles and adults in chimpanzees and in the Neanderthals, with young chimps and Neanderthals having flat brows and bulbous heads. So modern humans with our smooth foreheads and bubbleheads look immature compared to primitive Homo sapiens- we’re like giant children.
If the bones look immature, maybe the brain inside is too. Perhaps youthful creativity, imagination, faculty for languages, playfulness, why’s-the-sky-blue curiosity, willingness to make new friends, emotionality, were retained late in life in us, compared to them. We look more immature than them, maybe we acted that way.
Whatever it was, something seems to have happened that set us apart from the other humans. Modern humans are deeply weird- even, it seems, compared with other Homo sapiens. We gained abilities no other humans had, both in terms of our ability to make and destroy things. Unlike other humans, we learned to reshape not just a few stones into tools, but to reshape other species and the Earth to our ends. And with that ability, we did awesome, sometimes terrifying things no other human species did- we eliminated the other human species, wiped out the animals we hunted, tamed animals and cultivated plants, evolving them to fit our own ends. We made entire artificial ecosystems, farms and cities. Something happened to make us a different kind of human, and it decided our fate, and theirs.
Originally published at https://www.nicklongrich.com on February 11, 2021.
