RECENT NEWS of a new discovery, not yet published in a scientific journal, started us thinking. The story is this: World’s first dog lived 31,700 years ago. That article says: “The discovery could push back the date for the earliest dog by 17,700 years, since the second oldest known dog, found in Russia, dates to 14,000 years ago.”
Why is that important, and what does it have to do with Neanderthal extinction? Bear with us, as we provide a bit of background.
There’s a peculiar personality type that police are familiar with — they always call in to confess to whatever notorious crime has recently been reported. The phenomenon of “false confession” even has a Wikipedia entry. And so it is with the extinction of the Neanderthals — some people are eager to claim that we’re the guilty party. But are we?
It is estimated that about 90% of all identifiable species that ever existed have gone extinct. Humans have been around for only about 200K years, so we couldn’t have caused all that many of them. With extinction such a naturally-occurring event in the history of life on earth, why is it assumed that we’re responsible for the Neanderthals’ demise?
Let’s start with some facts — as best we can, given the admittedly sketchy evidence unearthed so far. Our information is mostly from the Smithsonian Institution’s Human Origins Program. After clicking around a bit, we learn that Homo neanderthalensis, or just plain Neanderthal, are known to have lived in Europe and western Asia (the Middle East), in a range from Britain to Iraq, starting about 200,000 years ago, and continuing to as recently as about 30,000 years ago. We’ve seen other estimates for the end of Neanderthal’s existence from 30K to 28K years ago.
Homo sapiens, or modern humans, may have come along a bit later than Neanderthal. Although DNA evidence suggests that we existed as early as 200K years ago, the oldest fossil evidence for anatomically modern humans is about 130K years old in Africa, and there is evidence for modern humans in the Middle East around 90K years ago — well after Neanderthal was living there. The earliest evidence yet found of modern humans in Europe is Cro-Magnon man, found at a location in France of that name, and believed to have lived about 35K years ago. They looked pretty much like Europeans do today, and if you met one he wouldn’t strike you as being alien in appearance.
Whatever dates one uses, it seems that Neanderthal was the first to arrive in Europe and the Middle East. They and modern humans co-existed in Europe starting around 35K years ago, perhaps earlier. Then, around 30K to 28K years ago, the Neanderthal was gone. That’s when they stopped appearing in the fossil record, after which we find only anatomically modern human forms.
What happened to the Neanderthals? No ancient battlefield has yet been discovered where fossil remains of Neanderthals and modern humans were both found, with weapons, and where death was clearly from combat injuries, indicated by unhealed skull fractures. Even if such a site were eventually found, it would be evidence only of one skirmish — that’s a long way from proof that we caused their extinction. The “false confession” crowd will continue to take the blame, but let’s try to get beyond that.
One proposed model for Neanderthal extinction is that our arrival in the Middle East and Europe was a catastrophe analogous to the devastation that European diseases brought to the native population of the New World after Columbus’ discovery. But that agonizing process in the New World took only a few short centuries, while modern humans and Neanderthals co-existed in Europe for at least 5,000 years, some say twice that long — and the two species’ co-existence was far longer in the Middle East. The disease scenario seems unlikely.
Climate has been suggested. There were a few glaciation episodes during our joint occupation of Europe. But Neanderthals are assumed to have been better adapted for cold than our ancestors. It was probably a rough situation for both species, with populations sometimes dipping to near-extinction levels. But we survived. Why?
For other speculations on this topic, see: Neanderthal extinction hypotheses. None of these hypotheses has gained substantial acceptance, and the subject of Neanderthal extinction remains unresolved.
This brings us to where we started this article — dogs! Our idea is that while humans formed an early and mutually beneficial relationship with dogs, the Neanderthals never did; and that is what made all the difference.
Wolf pups, the ancestors of all dogs, may have been taken to human settlements, or some unusually curious and well-disposed wolves may have wandered near our ancestors’ camps, perhaps as scavengers. Both events must have happened several times over the years. Gradually a population of human-compatible wolves began to live exclusively in association with human settlements, and thus became a separate breeding population, rarely interacting with their wolf cousins. The evolution of the dog had begun. These are not novel ideas. See: Origin of the domestic dog.
It probably didn’t take very long for dogs to emerge from their parent population. See: Tame Silver Fox (a/k/a Fox Farm Experiment), a Russian experiment that produced a breed of tame foxes after only 50 years of selective breeding.
… the foxes not only become more tame, but more dog-like as well: the new foxes lost their distinctive musky “fox smell”, became more friendly with humans, put their ears down (like dogs), wagged their tails when happy and began to vocalize and bark like domesticated dogs.
If that’s possible with foxes in a mere two human generations, it could have been similar with wolves, although we assume it took somewhat longer — unless our ancestors kept their dogs confined to prevent occasional interactions with wolves.
In the beginning, the latent talents of these dogs-in-the-making were essentially unused. They eventually accompanied our ancestors on the hunt, and served as pack animals, but such behavior probably developed over many years. Their herding abilities weren’t exploited until recently, when humans domesticated animals other than dogs. At first, the principal advantage of permitting dogs to live near human settlements was undoubtedly for their value as an alarm system. Having dogs sound the alarm of approaching danger could have made the difference between survival and disaster. We think it did make the difference, over and over again.
Also, although we’d rather not think about it, in times of scarcity there would be an obvious value in having a population of tame animals living nearby. Eating dogs is unpleasant for us to contemplate, but it’s certainly better than starving — or cannibalism. In difficult times, it may have been the difference between a clan’s survival or extinction.
Although there are several examples of Symbiosis in nature, it’s a most exceptional thing for one intelligent species to befriend another. It’s so unusual that, in all likelihood, not only did the Neanderthal fail to bond with dogs, but there were probably human settlements that failed to accomplish such a relationship. Perhaps many of those, like the Neanderthals, failed to survive. We shouldn’t overlook the fact that a pack of large, loyal dogs can be formidable comrades in battle, and this too may have played a role in determining which bands of humans survived and which went the way of the Neanderthal.
Therefore, not only are we responsible for the existence of dogs, but our own survival is due to the natural selection of our ancestors for their dog affinity. The two species selected each other and mutually contributed to our joint evolution — an example of of what biologists call coevolution. Those humans who befriended dogs are the ones that survived. They outlived the Neanderthals and became our ancestors. Our natural liking for dogs is literally part of our human nature.
This hypothesis — that dogs helped us survive while the Neanderthal failed — requires that humans and dogs were routinely living together — or at least in close, cooperative proximity — as far back as 30K years ago, when the Neanderthals went extinct. As we reported at the start of this article, evidence for such a long-term relationship may have been found.
Was our relationship with dogs older than that? It probably was. The Wikipedia article we cited above, Origin of the domestic dog, discusses DNA evidence that suggests “dogs separated from the wolf lineage approximately 100,000 years ago.” Tamed wolves may have had a very long association with our hunter-gatherer ancestors, but they lived and died in ways that their joint relationship doesn’t show up in the fossil record. The domestication of dogs may very well have preceded our mastery of fire, and should be regarded as one of early man’s greatest achievements.
This idea that we are indebted to dogs for our survival and our predominance over the Neanderthal must remain an hypothesis, as it can’t be supported by the mere absence of evidence of a Neanderthal-dog association. All we can say is that no such evidence has yet been found, so our hypothesis is viable. It could be disproved, of course, by a clear finding that dogs lived in close association with Neanderthals. That would leave unexplained the failure of Neanderthal. Until then, we’ll blame it on their rejection of dogs, and vice versa.
[Technical addendum: Another test, at least of the co-evolution hypothesis, would be the identification a rare genetic factor common to those who exhibit dog-intolerance,]
So the next time you experience a profound revulsion upon learning about a case of dog abuse, consider that your emotion may arise from the ultimate depths of your being. We know — we have always known — how valuable dogs are to us. And a dog abuser has more in common with the now-extinct Neanderthal than he does with us.
To return once more to the “false confession” crowd who are eager to take the blame for Neanderthal’s extinction, we say — it’s their fault, not ours. They were Neanderthals, and they didn’t like dogs.
Addendum: Here’s a link to an excerpt from Dawkins’ book, The Greatest Show on Earth. It’s not about Neanderthals, but it’s interesting nevertheless: Richard Dawkins: the truth dogs reveal about evolution.
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