A bleak outcrop in the Arctic Circle may have been one of the first places that domestic dogs were shaped into specific breeds. Researchers claim to have unearthed the earliest evidence of humans breeding dogs for a particular purpose: to pull sleds and hunt polar bears.
On a remote island in the frozen north, some 500 kilometers (300 miles) north of Russia, people were not only surviving but seemingly thriving 9,000 years ago. Making a living in the frigid environment, they took advantage of everything on offer, even the polar bears that stalked the ice. In fact, the people of Zhokhov Island are thought to be the only community even known to have hunted polar bears in large numbers using just spears and bone tools.
The bears supplemented a diet that mainly revolved around the reindeer that migrated through the region. At the time these hardy folk were living on Zhokhov, the sea level was lower and what is now an island was connected to Russia. It is thought that they would have followed the reindeer on their epic migration over the tundra. This could hold the clue as to why it was that dogs were being specifically bred here first, in a remote outpost on the fringes of the world.
The researchers think that the long distances traveled while hunting meant that humans had a very good reason to start breeding strong, rugged dogs that could pull sleds. After analyzing 11 fossil dog remains excavated on Zhokhov Island, the skulls were compared to that of Siberian huskies and wolves. The study, published in the Journal of Archaeological Science: Reports, found that the fossils were clearly much closer in proportions to the domestic dog than their wild counterparts.
Extrapolating from the fossils, the researchers estimated that the dogs being bred 9,000 years ago would have weighed somewhere between 16 and 25 kilograms (35 to 55 pounds), while the remains of what is thought to have been a dog-wolf hybrid tipped the scales at a hefty 29 kilograms (64 pounds). This is within the range for what a good sled dog typically weighs, as they need to be strong but not too big, otherwise they overheat.
The larger dog is thought to be a cross between a domestic dog and possibly a wolf, and the researchers postulate that the bigger animals may have been used to help with hunting the polar bears in the winter. This means that the breeding of dogs on Zhokhov, producing two distinct breeds, predates the previous earliest evidence of herding dogs being bred in the Levant, by around 2,000 years.
The evidence of domestic dogs is thought to stretch back at least 15,000 years, and the researchers think that in Siberia at least, humans may have been using them to pull sleds for much of this time.