7400 years ago Siberian dogs evolved to a much smaller size than wolves. So they depended on humans for food, including marine mammals and fish stuck under the ice, according to the new study.
The study helps to understand how the early dog population may have evolved, according to Robert Losey of the University of Alberta and lead author of the study, published Friday in the journal Science Advances.
“Long-term changes in dog diets have often been simplified,” he told AFP, explaining that previous work has focused on just two hypotheses to explain the transition from dogs to wolves, a process that began 40,000 years ago.
First, the friendlier wolves that turned to humans for meat became isolated from their wolf counterparts and were eventually tamed. Second, after the agricultural revolution, some dogs developed a better ability to digest starch.
To study the diet of ancient dogs in more detail, Robert Losey and his colleagues analyzed the remains of about 200 dogs that lived up to 11,000 years ago, and the same number of wolves.
“We looked for collections throughout Siberia, analyzed bones, took collagen samples, analyzed proteins in the laboratory,” he specified.
They found that dogs from 7,000 to 8,000 years ago were “already quite small, which means they just couldn’t do what most wolves could do,” Robert Losey said.
Thus, they were more dependent on humans for food or for hunting small prey rather than large prey that wolves could attack.
The researchers found that the dogs ate “fish, shellfish, seals and sea lions that he couldn’t easily catch on his own,” Losey noted. Such a diet they had “in places of Siberia, where lakes and rivers freeze for seven to eight months a year.”
Wolves, for their part, hunted at that time (and still) in packs for various types of deer.
These new diets brought their own advantages and disadvantages to dogs.
“Benefits because they had access to human food, which was usually light food, but in return they got all these new diseases and problems like malnutrition,” the researcher said.
If the new bacteria and parasites encountered had helped some to adapt (for example, by better digestion of carbohydrates), other populations would not have survived.