By Jennifer Viegas, Animal Planet News
Jan. 31, 2006 â€” Humans domesticated dogs between 13,000 and 17,000 years ago, according to one of the most extensive surveys of the earliest known dog burials.
This time window for domestication, which is when an animal becomes intimately associated with human beings, negates some prior theories based on gene changes that distinguish dogs from their wild wolf counterparts.
A few of those theories held that domestication occurred anywhere between 40,000 and 135,000 years ago.
The new study, published in the latest Journal of Archaeological Science, suggests that the bond between humans and dogs coincides with canine burials.
The earliest known probable dog remains date to around 17,000 years ago in central Russia, but the practice of burying dogs appears to have first begun between 15,000 and 14,000 years ago.
Burying dogs then became more common around 12,000 years ago.
Darcy Morey, author of the paper, told Animal Planet News that this period “was a time of major population expansion, starting with, for our purposes, colonization for the first time of eastern Eurasia and finally on into the New World. This is just me being mushy and fuzzy, but it seems that folks were a little more willing to try things, like drift into previously unoccupied expanses, and maybe engage in human-animal associations that resulted in domestication?”
Morey believes the canine genetic break from wolves may not be linked to domestication.
“Quite simply, if the dog and wolf genomes really did separate as long ago as some molecular studies have suggested, or even in that vicinity, the animals that were destined to become dogs must have made their living for some time essentially in the old-fashioned way, like wolves,” he said.
The burials reveal our evolving relationship with dogs. Often dog skeletons lay alongside human ones.
In one 7,000-year-old Swedish grave, archaeologists found the remains of a dog stretched out on the legs of a deceased man, as though the man hoped to hold and pet his canine friend for all eternity.
The dog’s neck was broken, indicating that it had been killed when its owner died.
Dogs buried without humans in North and Central America still show a loving touch and possibly a ritualized internment. A grave found in what is now Rhode Island, for example, contains a deceased prehistoric dog that was arranged to lie on its left side with its front paw under its head.
The age and condition of the dogs upon death also reveal domestication and the bond with humans, according to Morey.
He described a Middle Archaic burial dating from 6,700 to 7,180 years ago that was found in what is now Tennessee. The male dog discovered in the grave was “unusually old.”
Its skeleton indicated the animal suffered from traumatic injuries, arthritis, a persistent infection, and broken bones, some of which had healed, and some that had not.
“The pathological condition of this individual suggests that the owner insured the safety and well-being of the individual throughout its life since it is doubtful that, given all the traumatic and age degenerative manifestations, the dog could have survived in the absence of care,” Morey explained.
Christyann Darwent, an assistant professor of anthropology at the University of California at Davis, told Animal Planet News that she agrees with Morey’s time window for dog domestication.
“Dogs and humans could have been hanging out together long before 17,000 years ago, but domestication means we were manipulating their breeding, and that probably didn’t happen until more recently,” she said. “The burials represent some of the best evidence we have for the strong social ties that exist between dogs and humans.”
Darwent said domestication has benefited dogs and humans, but she suggested humans should take responsibility for their alteration of canines over the millennia.
“Some dogs, such as my own pet, are so reliant on humans that they could never fend for themselves in the wild,” she said. “We must remember that we have manipulated them so much with domestication that they often must depend upon us now for their survival.”
Copyright Â© 2006 Discovery Communications Inc.