You can thank cavemen for man’s best friend.

More than 9,000 years ago, natives of the Russian island of Zhokhov may have been the world’s first dog breeders, according to an article in the journal Science.

Hunters captured wolves and bred them into smaller canines to pull sleds and help hunt bears.

“They were clearly shaping these animals to do something special,” archaeologist Vladimir Pitulko wrote.

The people were likely driven to reduce the size of wolves because the animals, at 130 pounds, were too large to pull sleds and would overheat.