Washington (AFP)- 7,400 years ago, Siberian dogs evolved to be much smaller than wolves, making them more dependent on humans for food, including marine mammals and fish trapped under ice, according to a new report.
Robert Losey of the University of Alberta, who led the research published in Science Advances, said the findings helped explain the initial growth of the dog population as people put them to work in hunting, ranching and sledding. .
“Long-term dietary changes in dogs have really been oversimplified,” he told AFP, explaining that previous work has focused on just two main ideas to explain how dogs ceased to be wolves, a process that began about 40,000 years ago. .
The first of these was that the friendlier wolves approached human camps during the Ice Age in search of meat, eventually isolating themselves from their wild counterparts, later intentionally bred on dogs.
The second was that some dogs developed a better ability to digest starches after the agricultural revolution, which is why some modern dog breeds have more copies of the AMY2B gene that creates pancreatic amylase.
To further investigate the diets of ancient dogs, Losey and his colleagues analyzed the remains of about 200 ancient dogs from the last 11,000 years and a similar number of ancient wolves.
“We had to go to collections all over Siberia, analyze these bones, collect collagen samples and analyze proteins in the labs,” he said.
Based on the remains, the team made statistical estimates of the sizes of the bodies.
They also used a technique called stable isotope analysis to generate dietary estimates.
They found that dogs from 7,000 to 8,000 years ago “were already quite small, which meant they just couldn’t do the things most wolves did,” Losey said.
This, in turn, has led to a greater reliance on humans for food and a reliance on small prey and scavengers rather than the larger prey that wolves hunt.
“We see that dogs have marine diets, which means they eat fish, shellfish, seals and sea lions, which they can’t easily eat on their own,” he says.
Ancient dogs were found to eat fish “in regions of Siberia where lakes and rivers freeze for seven to eight months of the year.”
Wolves then and now hunted in packs and mainly preyed on various species of deer.
benefits and challenges
These new diets have brought both benefits and challenges for dogs.
“Benefit because they can access human stuff, and it’s often easy food, but they come with the costs of all these new diseases and problems, like lack of nutrition,” Losey said.
While the new bacteria and parasites they were exposed to may have helped some to adapt, some populations of dogs may not have survived.
Most of the first dogs in the Americas died, for obscure reasons, and were replaced by European dogs, although colonization is not to blame.
The surviving dogs acquired more diverse gut microbiomes, which helped them digest more carbohydrates associated with living with humans.
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