Early humans in Europe were able to dominate and eventually eradicate their Neanderthal cousin rivals thanks to early dogs bred from domesticated wolves that gave them a hunting advantage, an American anthropologist suggests.

Dogs, "man's best friend," prized for their loyalty and their abilities to chase and hunt, played a crucial role in modern humans taking over the continent 40,000 years ago and vanquishing the Neanderthals living there, says Professor Pat Shipman of Pennsylvania State University.

"At that time, modern humans, Neanderthals and wolves were all top predators and competed to kill mammoths and other huge herbivores," she explains. "But then we formed an alliance with the wolf and that would have been the end for the Neanderthal."

Her claim is a challenge to the conventional theory that wolves weren't domesticated until around 10,000 years ago, around the time of the rise of agriculture.

Shipman says she believes humans may have begun domesticating wolves and breeding dogs 70,000 years ago when modern humans first arrived in Europe from Africa.

At that time, Neanderthals dominated the continent and had done so for 200,000 years, yet within just a few millennia following the arrival of modern humans they were gone.

Some researchers have put that down to climate change that favored humans over Neanderthals, while other hold that humans' superior weapons and skill were the reason.

Shipman says she leans toward the latter explanation, but nominates wolves -- and from them the earliest dogs -- as important accomplices in the disappearance of the Neanderthals.

"Early wolf-dogs would have tracked and harassed animals like elk and bison and would have hounded them until they tired," she says. "Then humans would have killed them with spears or bows and arrows."

The dogs would not have to approach the large cornered animals to finish them off, exposing them to great danger, while humans were spared the energy output needed to track and wear down prey.

After the hunt both dogs and humans would share the meat, Shipman says, in "a win-win situation."

No evidence has been found to suggest Neanderthals ever made any attempt to domesticate wolves, she adds, suggesting they were on their own in hunting large prey for food, a dangerous undertaking at best.

Already stressed by the arrival of more modern humans, the competition for food resources may have been the last straw, Shipman says.

Now would it have stopped with Europe, she says; after the initial association there, dogs went with humans everywhere they went around the world helping them to succeed in hunting.

 "It has been a very powerful alliance," she says.