When Were Dogs Domesticated?

In 1914 quarry workers at Oberkassel, near Bonn in Germany, uncovered a double grave: a man of about 40, a woman of about 25, and among them bones of a canid. It took almost a century to realise how important that animal was. Now dated to about 14,200 years ago, it is the oldest undisputed domestic dog in the world.

It was also sick. A 2018 study by Luc Janssens and colleagues found that the puppy, about 28 weeks old, had suffered severe canine distemper and survived for weeks through the worst of it. That required someone keeping it warm, clean and fed. At the end of the last Ice Age, a dog was being nursed by people who had no practical reason to keep a sick puppy alive.

Dogs came from wolves — but not today’s wolves

All dogs descend from grey wolves (Canis lupus). That much is settled. What surprised geneticists was that no living wolf population is especially close to dogs. Modern wolves from Europe, the Middle East and China are all roughly equally related to them.

The explanation is that dogs came from a wolf population that has since gone extinct, one of many lost lineages of the Pleistocene. Genomes from the 35,000-year-old Taimyr wolf in Siberia, sequenced by Pontus Skoglund’s team in 2015, show that the split between the dog lineage and other wolves had already happened by then or soon after — though a genetic split is not the same as domestication, since the ancestors of dogs could have been a separate wild population for a long time before they became dogs.

In 2022 Anders Bergström and colleagues analysed 72 ancient wolf genomes spanning 100,000 years. Early dogs were closer to ancient wolves from eastern Eurasia than to western ones, and dogs in the Middle East and Africa later received extra ancestry from a separate, southwest Eurasian wolf population.

How early? The dating problem

Early dogs looked a lot like wolves, so the skeletons are hard to identify. Several skulls from sites like Goyet Cave in Belgium (about 36,000 years old) and Razboinichya Cave in Siberia (about 33,000 years) have been argued to be early dogs because their snouts are shorter and broader than wolves’. Many researchers suspect these are unusual wolves or failed, dead-end episodes of taming rather than the ancestors of today’s dogs.

In 2021 Angela Perri, David Meltzer and colleagues pulled genetic and archaeological lines together. They proposed that dogs were domesticated in Siberia around 23,000 years ago, during the harshest part of the last Ice Age, when people and wolves were isolated together in the same refuges. From there, dogs spread west into Eurasia and east with the people who went on to settle the Americas. It is an attractive model, but still a hypothesis.

How does a wolf become a dog?

There are two classic scenarios.

Self-domestication

Wolves that were less fearful of people scavenged around camps. Over generations, selection for tolerance produced tamer animals, with the physical side-effects that often accompany tameness — floppier ears, shorter faces, varied coats, as seen in Dmitry Belyaev’s famous Russian fox-taming experiment.

Hunters sharing surplus meat

A 2021 study by Maria Lahtinen and colleagues added a twist. Ice Age hunters on a diet of lean game hit a problem: humans can only safely get a limited share of calories from protein. In winter, they would have had surplus lean meat they could not eat themselves. Wolves can live on pure protein for months. Sharing leftovers with captured or tolerated wolf pups would cost people nothing.

Whatever the mechanism, the result was an animal that could read human gestures — even puppies follow pointing better than hand-raised wolves — and that could help with hunting, hauling, guarding and warmth.

Dogs changed with us

A 2020 study led by Bergström sequenced 27 ancient dogs from across Europe, the Near East and Siberia. By 11,000 years ago, before any other animal was domesticated, there were already at least five distinct dog lineages: in the Levant, Karelia near the Baltic, Lake Baikal, the Americas and New Guinea.

Dogs then adapted to farming life. Many modern dogs carry extra copies of AMY2B, a gene for digesting starch, which spread after people began growing grain. Arctic sled dogs, by contrast, have few copies and adaptations to a high-fat diet.

What happened to the first American dogs

Dogs crossed into the Americas with people at least 10,000 years ago and were present across the continent for millennia. After European contact, those lineages were almost entirely replaced by European breeds. A 2018 study by Máire Ní Leathlobhair and colleagues found that the closest living relative of pre-contact American dogs is not a dog at all, but a transmissible venereal tumour: a cancer that began in one dog thousands of years ago and still spreads between dogs around the world.

Did Neanderthals have dogs?

There is no evidence they did. The anthropologist Pat Shipman has proposed that dogs may have given Homo sapiens a hunting advantage over Neanderthals in Europe, contributing to their decline. Given that most secure dates for domestication postdate Neanderthal extinction around 40,000 years ago, the idea remains speculative.

Why it matters

Dogs are the only animal domesticated by hunter-gatherers rather than farmers. That makes them a window into the Ice Age mind: people who could form a working, affectionate relationship with a large predator, and who would bury a sick puppy with their own dead.