Ancient dogs specially adapted to the cold have been helping humans survive in the Arctic for a surprisingly long time—more than 10,000 years—a new study suggests. "Until now, we have thought that sledge dogs were only [2,000 to] 3,000 years old," says Mikkel Sinding, a University of Copenhagen geneticist and co-author of the study in Science. But in comparing DNA from a dog that lived 9,500 years ago on Zhokhov Island, where evidence of early dog sleds has been found, to the genetics of modern sled dogs (including Alaskan and Siberian huskies, Alaskan malamutes, and dogs in Greenland), researchers found they share many of the same genes. "This means that modern sledge dogs and [the Zhokhov dog] had the same common origin in Siberia more than 9,500 years ago," says Sinding.
Dogs in Greenland, for example, don't seem to have changed much from their Zhokhov ancestor. “It’s largely the same dogs doing the same thing,” Sinding says. It's not clear when the first sled dog was domesticated, but the Zhokhov dog was already "a long way down the path to domestication," Sinding tells New Scientist. Like modern sled dogs, it had long fur and thick pads on its feet. Modern sled dogs may have also received from their ancestors an adaptation allowing them to thrive on a fat-rich diet. Ice Age Siberians probably didn't mind sharing their hunted seals and polar bears. As co-author Shyam Gopalakrishnan tells NBC News, the ability "to move large amounts of material, kills and food across large spaces in such difficult terrain" was perhaps "instrumental in humans settling the Arctic." (Read more dogs stories.)