Dogs may have become domesticated because our ancestors had more meat than they could eat. During the ice age, hunter-gatherers may have shared any surplus with wolves, which became their pets.
The timing and causes of the domestication of dogs are both uncertain. Genetic evidence suggests that dogs split from their wolf ancestors between 27,000 and 40,000 years ago. The oldest known dog burial is from 14,200 years ago, suggesting dogs were firmly installed as pets by then.
But it isn’t clear whether domestication happened in Europe or Asia – or in multiple locations – or why it happened. Dogs are the only animals domesticated by hunter-gatherers: all the others were domesticated after farming became widespread. One suggestion is that people domesticated dogs to help them with hunting, while another scenario has wolves scavenging human waste dumps and becoming accustomed to people.
Maria Lahtinen of the Finnish Food Authority in Helsinki and her colleagues suggest that the key may have been a surfeit of meat.
Dogs were domesticated when ice sheets covered much of northern Eurasia and the climate was colder than today. During this time, humans and wolves would have competed for food, as both are top predators.
However, wolves can survive on nothing but lean meat – which contains protein and little else – for months. In contrast, humans cannot. There are limits to how much protein our bodies can handle, so we have to eat other food groups such as fat as well. “We are not fully adapted to eat meat,” says Lahtinen.
Her team calculated how much food was available during the Arctic winters, based on the prey species living there. They found there was an excess of lean meat, suggesting human hunters would have ended up with more of this than they could consume. Wolves could have eaten this surplus, implying the two species weren’t in competition during the harsh winters. Instead, humans could have shared lean meat with wolves without losing out themselves.
Lahtinen suggests that hunter-gatherers may have taken in orphaned wolf pups – perhaps viewing them a bit like pets – and fed them on spare lean meat. They probably didn’t have any long-term goal in mind, but the tamed wolves would have later proved to be useful hunting partners – reinforcing the domestication. “They must have been very attractive for hunter-gatherers to keep,” says Lahtinen.
Journal reference: Scientific Reports, DOI: 10.1038/s41598-020-78214-4
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Source: Humans - newscientist.com
