Washington (AFP) – As early as 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 the ice, according to a new report of research published Friday.
Robert Losey of the University of Alberta, who led the study published in the journal Science Advances, said the findings help explain the early development of dog populations when people introduced them to hunting, herding and breeding. and sledding. .
“Long-term dietary changes in dogs have really been oversimplified,” he told AFP, explaining that previous work had focused on only two ideas. key to explaining how dogs changed from wolf to wolf, a process that began about 40,000 years ago.
The first of these were the friendlier wolves that approached human camps during the Ice Age for meat, eventually isolating themselves from their wild counterparts, and then deliberately bred as dogs.
The second is that some dogs developed a better ability to digest starch after the agricultural revolution, which is why some modern dog breeds have multiple copies of the AMY2B gene that produces pancreatic amylase.
To further investigate the diets of ancient dogs, Losey and his colleagues analyzed the remains of about 200 ancient dogs from 11,000 years ago and a similar number of ancient wolves. grand.
“We had to go to collections all over Siberia, analyze those bones, take collagen samples and analyze proteins in the lab,” he said.
Based on what was left, the team came up with a statistical estimate of body size.
They also used a technique called stable isotope analysis to generate dietary estimates.
They found that dogs 7,000 to 8,000 years ago “were pretty small, meaning they couldn’t do the things that most wolves did,” Losey said.
This has resulted in humans being more dependent on food and dependent on small prey and scavengers, than on the larger prey that wolves hunt.
“We’ve found that the dogs are on a marine diet, which means they eat fish, shellfish, seals and sea lions, which they can’t easily get,” he stated.
Ancient dogs have been discovered eating fish “in parts of Siberia, where lakes and rivers freeze for seven to eight months of the year.”
Wolves then and now hunt in packs and prey primarily on various deer species.
Benefits and Challenges
These new diets have brought both benefits and challenges for dogs.
“It’s beneficial because they have access to things from humans, and often food, easily, but they come at the expense of all these new diseases and problems, such as undernutrition,” says Losey. .
While the new bacteria and parasites they were exposed to may have helped some dogs to adapt, some dog populations may not have survived.
Most of the first dogs in the Americas died, for puzzling reasons, and were replaced by European dogs, though to no avail.
The dogs that survived had a more diverse gut microbiome, which helped them digest more carbohydrates associated with living with humans.
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