A pair of dog skulls uncovered in digs in Siberia and Belgium, each 33,000 years old, show dogs were domesticated long before any other animal, including sheep, cows or goats.

The skulls had shorter snouts and wider jaws than wild animals, such as wolves, which use their long snouts to hunt. It suggests dogs were used for companionship and protection.

Scientists used carbon dating to determine the age of the skulls, then examined the bone structures.

“Both the Belgian find and the Siberian find are domesticated species based on morphological characteristics,” said Greg Hodgins, researcher at the University of Arizona’s Accelerator Mass Spectrometry Lab.

“Essentially, wolves have long thin snouts and their teeth are not crowded, and domestication results in this shortening of the snout and widening of the jaws and crowding of the teeth.

“The interesting thing is that typically we think of domestication as being cows, sheep and goats, things that produce food through meat or secondary agricultural products such as milk, cheese and wool and things like that.

“Those are different relationships than humans may have with dogs. The dogs are not necessarily providing products or meat. They are probably providing protection, companionship and perhaps helping on the hunt. And it’s really interesting that this appears to have happened first out of all human relationships with animals.”