The Bonn-Oberkassel dog is not the only ancient hound to have received such honors. In Israel, at Ain Mallaha, a hunter-gatherer site dating to 12,000 years ago in the upper Jordan Valley, archaeologists discovered what is perhaps the most famous dog-human burial. The skeleton of an elderly person lies curled on its right side, its left arm stretched out under the head, with the hand resting gently on a puppy. The dog was about four to five months old and was placed there, archaeologists think, to be a companion to the deceased. Unlike the Pˇredmostí dogs, this puppy was not battered; its remains were arranged lovingly with someone who may have cared for it.
Beginning at least 15,000 years ago and probably somewhat earlier, Perri says, hunter-gatherers in Europe, Asia and the Americas began depending on their dogs hunting skills for survival. Researchers cannot trace a direct genetic line from those animals to our pet pooches; nevertheless, they say, these animals were unquestionably dogs. “Good hunting dogs can find fresh tracks, and guide the hunters to the prey, and hold them at bay,” says Perri, who has joined traditional hunters and their dogs in Japan and the U.S. “When people start using dogs for hunting, you see a switch in how people view them, and you start finding dog burials across the world.” Such burials are not rituals or sacrifices, she emphasizes. “These are burials of admiration, where the dogs are interred with ocher, stone points and blades—male tools of hunting.”
One of the most elaborate dog burials comes from Skateholm, Sweden, and is dated to about 7,000 years ago. Several dogs were found interred in the same area with dozens of humans. One was particularly celebrated and given the finest treatment there of anyone, human or dog. “The dog was laid on its side, flint chips were scattered at its waist, and red deer antlers and a carved stone hammer were placed with it, and it was sprinkled with red ocher,” Perri says. There is no indication of why this dog was so revered, but she suspects it must have been an excellent hunter and that its human owner mourned its death. “You see this relationship among hunters and their dogs today and in the ethnographic record,” Perri observes, noting that Tasmanian hunter-gatherers in the late 19th century were quoted as saying, “Our dogs are more important than our children. Without them, we couldnt hunt; we wouldnt survive.”
Analyzing whole genomes of living dogs and wolves, last Januarys study revealed that todays Fidos are not the descendants of modern gray wolves. Instead the two species are sister taxa, descended from an unknown ancestor that has since gone extinct. “It was such a long-standing view that the gray wolf we know today was around for hundreds of thousands of years and that dogs derived from them,” says Robert Wayne, an evolutionary geneticist at the University of California, Los Angeles. “Were very surprised that theyre not.” Wayne led the first genetic studies proposing the ancestor-descendant relationship between the two species and more recently was one of the 30 co-authors of the latest study, published in PLOS Genetics, that debunked that notion.
Larson suspects that several geographically disparate populations of the ancestral wolf species may have contributed to the making of todays dog. It would not be the first time such a thing happened: Larson has shown that pigs were domesticated twice—once in the Near East and once in Europe. Intriguingly, enigmatic fossils from Belgium, the Czech Republic and southwestern Siberia that date to between 36,000 and 33,000 years ago and exhibit a mix of wolf and dog features hint at the possibility of at least three independent instances of domestication attempts from an ancestral wolf. But the anatomical characteristics of these fossils alone cannot answer the question of where dogs came from.
How did dogs become man’s best friend?
Perhaps more intriguing then exactly when or where dogs became domesticated is the question of how. Was it really the result of a solitary hunter befriending an injured wolf? That theory hasn’t enjoyed much scientific support.
One similar theory argues that early humans somehow captured wolf pups, kept them as pets, and gradually domesticated them. This could have happened around the same time as the rise of agriculture, about 10,000 years ago. The oldest fossils generally agreed to be domestic dogs date to about 14,000 years, but several disputed fossils more than twice that age may also be dogs or at least their no longer entirely wolf ancestors.
Since more recent genetic studies suggest that the date of domestication occurred far earlier, a different theory has gained the support of many scientists. “Survival of the friendliest” suggests that wolves largely domesticated themselves among hunter-gatherer people.
“That the first domesticated animal was a large carnivore, who would have been a competitor for food—anyone who has spent time with wild wolves would see how unlikely it was that we somehow tamed them in a way that led to domestication,” says Brian Hare, director of the Duke University Canine Cognition Center.
But, Hare notes, the physical changes that appeared in dogs over time, including splotchy coats, curly tails, and floppy ears, follow a pattern of a process known as self-domestication. It’s what happens when the friendliest animals of a species somehow gain an advantage. Friendliness somehow drives these physical changes, which can begin to appear as visible byproducts of this selection in only a few generations.
“Evidence for this comes from another process of domestication, one involving the famous case of domesticated foxes in Russia. This experiment bred foxes who were comfortable getting close to humans, but researchers learned that these comfortable foxes were also good at picking up on human social cues,” explains Laurie Santos, director of the Canine Cognition Center at Yale University. The selection of social foxes also had the unintended consequence of making them look increasingly adorable—like dogs.
Hare adds that most wolves would have been fearful and aggressive towards humans—because that’s the way most wolves behave. But some would have been friendlier, which may have given them access to human hunter-gatherer foodstuffs..
“These wolves would have had an advantage over other wolves, and the strong selection pressure on friendliness had a whole lot of byproducts, like the physical differences we see in dogs,” he says. “This is self-domestication. We did not domesticate dogs. Dogs domesticated themselves.”
A study last year provided some possible genetic support for this theory. Evolutionary biologist Bridgette von Holdt, of Princeton University, and colleagues suggest that hypersocial behavior may have linked our two species and zero in on a few genes that may drive that behavior.
“Generally speaking, dogs display a higher level of motivation than wolves to seek out prolonged interactions with humans. This is the behavior I’m interested in,” she says.
Von Holdt’s research shows that the social dogs she tested have disruption to a genomic region that remains intact in more aloof wolves. Interestingly, in humans genetic variation in the same stretch of DNA causes Williams-Beuren syndrome, a condition characterized by exceptionally trusting and friendly behaviors. Mice also become more social if changes occur to these genes, previous studies have discovered.
The results suggest that random variations to these genes, with others yet unknown, may have played a role in causing some dogs to first cozy up with humans.
“We were able to identify one of the many molecular features that likely shape behavior,” she adds.
Dogs of similar size to a wolf share a similar life expectancy (12-14 years in captivity). They both display similar body language at times and share an impeccable sense of smell. Both species also thrive within a pack environment and exhibit a prey drive.
Dogs and wolves have many outward similarities. After all, the two species descend from a common ancestor. In fact the two species share 98.8% of the same DNA. They can even interbreed (although their offspring are typically not fertile).
When you start to really dig, though, there are no bones about it: dogs and wolves may be more different than they are the same.
The more you explore the differences between the two species, the more it becomes apparent that they are really not the same thing at all. We have bred our household dogs to suit our needs and lifestyles, and it is important to remember that they need us as well. Wolves may not “need” dental care, parasite prevention, or vaccines, but your dog is not a wolf. We are happy to help you with your canine companion. We couldn’t imagine life without our furry, albeit domesticated, friends.
It is arguably one of modern pet marketing’s most reliable angle: put a picture of a wolf on about anything designed for the canine species and it is a hit. But how much does your Pomeranian really have in common with Canis lupus? Join Schertz Animal Hospital as we explore the differences and similarities between dogs and wolves.