How did wolves become dogs?

Dogs descend from grey wolves, specifically from an ancient wolf lineage that is now extinct. They were domesticated by hunter-gatherers more than 15,000 years ago, and they are the only large carnivore ever domesticated. Every other domesticated species came later, from farming societies. The exact process is still debated, but most experts now think wolves took a large part in domesticating themselves by living near people. [1] [2]

The timing is unsettled. The Natural History Museum says the process may have begun around 30,000 years ago, during the last ice age, and that recognisable dog bones about 15,000 years old have been found in various places. A molecular clock analysis of hundreds of modern and ancient dog genomes, described by the Smithsonian, points to roughly 20,000 to 22,000 years ago. The International Wolf Center says scientists generally agree on 15,000 to 20,000 years ago. [3] [4] [5]

The place is also unclear. Some ancient DNA evidence suggests domestication happened twice, in eastern and western Eurasia, with the two groups later mixing into the ancestor of all living dogs. Bones are hard to interpret, because it can be difficult to tell an early dog from a wild wolf. The earliest dog the Smithsonian identifies is a 14,000-year-old pup from Bonn-Oberkassel, Germany. [4]

The older idea, proposed by Francis Galton in 1907, was that people took wolf pups, brought them to camp and raised them as pets. Scientists later judged that domestication is a long process taking hundreds or thousands of years, so people who started with a cute pup would have ended up with a wild animal. Science reports that most experts now favor self-domestication. [2]

In the self-domestication view, wolves were drawn to human campsites by the smell of cooking meat and discarded scraps. Less fearful and less aggressive wolves fed there, survived longer and produced more pups, so each generation grew bolder. The Natural History Museum adds that friendlier wolves may have been tolerated and later helped by guarding camps or aiding hunts. Greger Larson and Dorian Fuller, cited by the International Wolf Center, argue that a wolf population could have become an ecotype suited to following mobile hunter-gatherers, as other wolf and fox populations have specialized on particular prey and habitats, and later been shaped by more intensive human selection. [2] [3] [5]

The minority position, defended by biologists David Mech and Luc Janssens in a 2021 paper, rejects self-domestication for several reasons. They argue that humans took pups from dens, and that pups raised by people tame easily, stay close to their food source and remain friendly. People then kept the most cooperative ones and bred them over many generations. They suggest the main motive was companionship, though earlier researchers proposed help with hunting, guarding, cleaning up waste, or food. The Natural History Museum also mentions a related theory that humans actively domesticated dogs to help hunt large mammals. [5] [3]

Science describes a later phase in which people, having seen the usefulness of these animals, bred them to be better hunters, herders and guardians. A comparison of thousands of ancient dog and wolf skeletons found flattened vertebrae tips in ancient dogs, suggesting they hauled heavy packs, and missing rear molars that may indicate a bridle for pulling carts. [2]