Scientists have found the world's oldest drawings of pet dogs in 8,000-year-old hunting scenes etched into rock walls in Saudi Arabia, suggesting that humans were training canines even before they settled down into farming communities.
While documenting thousands of rock-art panels from the sites of Shuwaymis and Jubbah in Saudi Arabia, researchers from the Max Planck Institute for the Science of Human History in Germany counted 156 dogs at Shuwaymis and 193 at Jubbah.
The dogs in the engravings have pricked ears, short snouts and curled tails - similar to the modern Canaan breed in their appearance.
They look distinct from the hyenas and wolves depicted elsewhere in the rock-art panels, according to a study published in the Journal of Anthropological Archaeology.
The dogs are often shown helping humans hunt lions, ibexes, gazelles, horses and other prey.
Some dogs in the hunting packs are on leashes, tethered to the waists of hunters, whose hands are then free to shoot arrows.
The researchers speculated that these leashed dogs might represent young dogs in training, older ones at risk of injury or valuable scent dogs, the 'Live Science' reported.
"This suggests not only are some human populations controlling their hunting dogs by the Pre-Neolithic but that some dogs may perform different hunting tasks than others," researchers said.
"Some may be used only to track prey scents, while others are used to corral and attack prey, protect human hunters, or help haul meat back to camp," they said.
Genetic and archaeological evidence suggests that dogs were domesticated from a grey wolf ancestor at least 15,000 years ago, and perhaps as early as 40,000 years ago.