Dogs have been a loyal companion to mankind for more than 30,000 years, it has been revealed.
Scientists believe that two, 33,000-year-old skulls unearthed in separate digs in Siberia and Belgium show dogs were domesticated long before any other animal, including sheep, cows or goats.
The skulls had shorter snouts and wider jaws than undomesticated animals like wolves, which use their longer snouts and narrower jaws to help them hunt, according to researchers from the University of Arizona
This means the dogs had been kept for protection and companionship by our ancient ancestors - just like they are today.
The researchers believe dogs could have been the first species of animals to be domesticated by humans, before farm animals were bred for their meat and skins. This offers an explanation for why breeds like pugs and huskies look so different, despite being the same species.
Carbon dating was used to determine the age of the two skulls and the bone structures were analysed, leading researchers to conclude that the domesticated dogs were "pretty solid."
"Both the Belgian find and the Siberian find are domesticated species based on morphological [structural] characteristics," study author Greg Hodgins said.
"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," said Dr Hodgins, whose findings were published in the journal PLoS ONE.
"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.
"This appears to have happened first out of all human relationships with animals."
- DAILY MAIL