Ice Age hunters’ leftovers may have fueled dog domestication

Sometime between around 29,000 and 14,000 years ago, hunter-gatherers navigating northern Eurasia’s frigid landscapes turned wolves into dogs by feeding them lean-meat leftovers.

That, at least, is a likely scenario that would have benefited both wolves and people, say archaeologist Maria Lahtinen of the Finnish Food Authority in Helsinki and colleagues. In harsh Ice Age winters, when game hunted by both species was lean and fat-free, prey animals would have provided more protein than humans could safely consume, the researchers conclude January 7 in Scientific Reports. People could have fed surplus lean meat to captured wolf pups being raised as pets because the animals wouldn’t have had the same dietary limitations, the team proposes.

That idea is largely based on inferences from previous research on how ancient hunter-gatherers survived in arctic environments and new calculations suggesting that, for dietary reasons, Ice Age groups could not have eaten all of the lean meat that was hunted. Though far from the final word on the controversial origins of dogs (SN: 5/21/15), Lahtinen’s group offers a novel take on how that process may have unfolded.

The researchers’ calculations assume that, like some arctic hunter-gatherers today, ancient humans acquired 45 percent of their calories from animal protein. Humans can’t eat a completely carnivorous diet because of the liver’s ability to generate only part of our energy needs from protein. Edible plants could have been stored for the winter as a source of carbohydrates, but supplies would have waned as the annual big freeze wore on, the scientists suspect. So Ice Age hunter-gatherers probably reached a point where they focused on hunting in order to extract fatty marrow and grease from the bones of prey to meet energy needs, the researchers argue, leaving plenty of lean meat untouched and available as wolf food.

Competition between humans and wolves for prey would have declined as generations of pet wolves gradually evolved into dogs, the team hypothesizes. Only then, the idea goes, were more docile canines trained to help people (SN: 3/21/15).