The first people to settle the Americas did not walk alone. They brought dogs, says a new study based on archaeological and population genetics analyses of both humans and canines. Moreover, the extraordinary relationship between the two competing species – they competed over animals – may have arisen as an indirect result of the horrible Siberian weather over 23,000 years ago,the researchers postulate.
The new paper postulating a Siberian origin of dog domestication, published Monday in Proceedings of the National Academy of Sciences by an international team led by archaeologist Angela Perri of Durham University in the U.K., isn’t revisiting the argument over when humans reached the Americas. It is revisiting the argument about when and where dogs were domesticated, based on population genetics.
The archaeological evidence suggested as “early dogs,” as opposed to wolves, is highly controversial. Dogs were apparently the only animal to be domesticated during the Paleolithic, possibly even tens of thousands of years before the Neolithic revolution that changed us from nomadic hunter-gatherers to settled farmers (which happened at different times in different places). But there is no consensus about when we find “dogs” as opposed to wolves in the archaeological record. The earliest generally accepted dog dates to about 15,000 years ago in Bonn-Oberkassel, Germany: there are several sites in Europe that may have earlier evidence, but the question is of what. The earlier the “dog,” the more like a wolf it looked like.
But if we have a dog 15,000 years ago in what is Germany today, then certainly domestication was earlier. And crucially, the new paper compares genetic results for humans and dogs from Siberia, Beringia and North America. It finds close correlation in the movement and divergences of human and dog lineages, and makes the case that our dogs were probably domesticated from wolves at least 23,000 years ago, possibly in Siberia.
Fine dining in prehistoric Siberia
What happened in Siberia around 23,000 years ago? That was the time of the Last Glacial Maximum, which lasted until around 19,000 years ago, and was terribly cold and arid. At least the land was not glaciated, which would have rendered it pretty much uninhabitable.
But humans and wolves were isolated together during this harshest period of the last Ice Age, the authors of the new study explain.
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That makes it sound like human and hound discovered the delight of cuddling in front of the cave-fire, but that presumably came later. The initial driver was more likely proximity as the two freezing, hungry species hunted the same animals.
Wolves would skulk around kills by humans, who may or may not have shared meat because they couldn’t possibly eat any more; we would have scavenged from wolf kills too, as one does. Our relationship with our best friend likely began with the delight of mutual scavenging, the authors and many others suggest.
“When and where have long been questions in dog domestication research, but here we also explored the how and why, which have often been overlooked. Dog domestication occurring in Siberia answers many of the questions we’ve always had about the origins of the human-dog relationship,” Dr. Perri said.
Moving on a few thousand years to the Americas, the time line of human arrival is debated but there is consensus that it was at least 15,000 years ago, and they then spread through the New World very fast. Data suggesting earlier arrival remains controversial (where some see a stone tool, others see “just a rock”). Archaeological evidence of dogs in the Americas goes back to around 10,000 years but absence of earlier evidence isn’t evidence of absence.
We note that uncertainty is a feature of biology, the study of the infinitely complex. One genetic study of modern and ancient dogs done in 2016 concluded that they were domesticated twice, once from wolves in Europe and once from wolves in Asia, then the two met and mixed. A different genetic analysis published the next year concluded that dogs had been domesticated just once around 40,000 years ago, then split into European and Asian groups around 20,000 years ago. It seems, by the way, that the wolf population from which dogs arose is extinct.
Among the few certainties in life is that dogs weren’t domesticated in America; that maybe early humans could sail (or not) but dogs can’t; so dogs were domesticated before people reached the Americas; and that if the first Americans came from Siberia and brought dogs, then the dogs in Siberia had been domesticated.
I am dog, hear me ignoring you
Supporting their theory that dogs accompanied the first humans to America, authors of the new study cite separate studies finding correlation of historic spreading by humans with dogs – their movements and genetic divergences correlated. For instance, genetic evidence suggests dogs came to Southeast Asia with people multiple times; archaeological remains suggest dogs reached Australia around 3,500 years ago; they would be the forefathers of the dingo. New Zealand only got its first dogs in the 13th century C.E., with roaming Polynesians. Point is, the domesticated dog didn’t spread worldwide on its own.
So what can we say? The earliest Americans were of northeast Asian descent; the Americas were the last super-region world to be peopled; and by the time people were crossing the Bering land bridge, dogs had been domesticated. They may even have already become trained to pull sleds. Archaeological evidence found on the Siberian island of Zokhov indicates that sledding by dog was a way of life there 9,000 to 8,000 years ago – at which time it hadn’t been an island, it was connected to mainland Siberia.
“We have long known that the first Americans must have possessed well-honed hunting skills, the geological know-how to find stone and other necessary materials and been ready for new challenges. The dogs that accompanied them as they entered this completely new world may have been as much a part of their cultural repertoire as the stone tools they carried,” suggested co-author and archaeologist David Meltzer of Southern Methodist University, Texas.
Finally, they may not look it, but dogs today all belong to one species, a genetically homogeneous group with varying degrees of traits from three ancestral lineages: the western Eurasian lineage, which characterizes mostly European, Indian and African dogs; an east Asian lineage now typified by the dingo; and an Arctic lineage that bequeathed us the husky and the earliest dogs in America. A separate study of ancient dog genomes posits that all three lineages have existed for at least 11,000 years.
So there we have it. It seems husky-like dogs had long been domesticated and trekked to the Americas over the land bridge with hunter-gatherers, who arose from a group of paleo-Siberians who had been isolated for thousands of years, if only because of the weather. There is no evidence of genetic mixing between that group and others since the Late Glacial Maximum began 23,000 years ago, a period of isolation that lasted at least 2,500 years but possibly as long as 9,000, some researchers suspect.
And now we get to the crux of the theory of why the dog may have been domesticated in Siberia.
If the humans who reached the Americans were first isolated in Siberia during the Late Glacial Maximum for thousands of years, where did they get their dogs?
As said, the evidence indicates one or two domestication events, not more; also, if the dog had been domesticated in western Eurasia, then its spread eastward into Siberia would have required far-ranging human migration before the isolation, and the genetic evidence suggests otherwise. Moreover, the first dogs in America genetically cluster with Arctic dogs, suggesting they weren’t an ancestral population, but rather that both were descendants of the ancestral dogs.
The most parsimonious explanation is that the dog was domesticated in Siberia and spread from there. Certainly it had reached the Near East too by 15,000 years ago, from which time we start to find dog burials indicating that they were held dear, at least in some places.
In any case the husky-like dogs accompanying the paleo-Siberians and future paleo-Native Americans on their journeys may or may not have already been able, and willing, to pull sleds.
Some 15,000 years later husky-like dogs – let’s not get too particular about their pedigree – would accompany Russian immigrants to the Land of Israel, where both would become firmly established.
The proud owners of such thick-furred exotica, unfazed by their marked unfitness to the hot, dry clime of the Middle East, evidently weren’t too particular about their dogs’ mating choices and the result is that Israel has become thronged with blue-eyed dogs; small ones, big ones, black ones and brown ones, white and multicolored and unabashedly mixed-breed, more or probably less obeying their owners’ commands in Hebrew – not a subservient lot, huskies – and looking at you with eyes the color of the sky. Good luck trying to get them to pull your sled.