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Human hunters bagged more game than they could safely eat during the last Ice Age.
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Instead of wasting excess meat, they fed it with wolves, which evolved into domesticated dogs over time, a new study suggests.
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Dogs are hard to resist when they beg for scraps of food. Feeding hungry canines with leftovers may have boosted the domestication of dogs during the last Ice Age, new research suggests.
A study published on Thursday in the journal Scientific Reports suggests that humanity’s bond with dogs began in northern Eurasia between 14,000 and 29,000 years ago, when much of the Earth was covered with ice.
The plants were scarce and the prey was thin during those harsh winters of the Ice Age. Our hunter-gatherer ancestors obtained only 45% of the calories they needed to survive on lean meat, since too much can cause protein poisoning (human livers are not well adapted to metabolize proteins). In the absence of plant-based carbohydrates, our ancestors depended on animal fat and grease to supplement their diet.
In order to gain enough weight, however, hunters had to kill more skinny animals like deer and moose than they could eat whole.
Thus, Ice Age hunters fed wolves excess meat, according to Maria Lahtinen, lead author of the new study and archaeologist at the Finnish Food Authority.
“The wolf and the human being can form a partnership without competition in cold weather. This would easily promote domestication,” Lahtinen told Business Insider.
The offspring of leftover-eating wolves eventually became the first domesticated dogs, their study suggests.
There are many benefits for domesticated dogs: they can pull sleds, protect livestock or provide protection from other predators.
But none of these benefits became apparent until long after dogs’ wolf ancestors were domesticated. Therefore, scientists have long wondered about the initial reasons for the domestication of dogs.
The question was especially disconcerting, since the ancient humans and northern wolves that occupied Eurasia tens of thousands of years ago subsisted on the same prey, such as caribou, rabbits and deer. Many researchers found it unlikely that the two species would have chosen to cooperate voluntarily, given the limited sources of food during the Ice Age.
“Humans have a tendency to try to eliminate other competitors,” said Lahtinen, adding, “it has never been explained before why humans joined forces with a competitor.”
Before this new study, one hypothesis was that wolves were opportunistic scavengers who were so attracted by the waste of food that humans left behind that the two species eventually adapted to live side by side. The problem with this thought, however, was that the Ice Age humans have not settled anywhere long enough to leave consistent, disposable remains, according to Lahtinen and his coauthors.
Therefore, it may be more plausible that our ancestors would simply capture more prey than they could safely consume and choose to satiate their predatory companions instead of killing them.
This led four-legged predators to get closer and closer to people over time until they evolved into dogs, a process that occurred sometime between 20,000 and 14,000 years ago, suggests Lahtinen’s research.
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