The marks on the teeth of ancient dogs speak of their domestication - they gnawed the bones that humans left for them, according to American scientists. There are no such obvious signs of wear on the teeth of wolves - their main food was the flesh of herbivores. Comparing canine teeth shows evidence of domestication even before other signs begin to show, the researchers note.
A team led by anthropologist Peter Ungar of the University of Arkansas has found new evidence for the domestication of dogs in the Paleolithic era - marks on the teeth indicating that they were actively gnawing bones. Wolves, which hunted for food and ate animal flesh, had much fewer such tracks. The work was published in the Journal of Archaeological Science.
In the east of the Czech Republic, there is the archaeological site of Předmosti. Excavations have been conducted there since the end of the 19th century. Among the finds are the remains of people, mammoths, hares, the ancestors of wolves and dogs, as well as tools of the Neolithic era.
The domestication of dogs is the earliest example of animal husbandry and the only form of domestication that took place long before the advent of agriculture.
It happened about 15-40 thousand years ago, but the exact timing and reasons are still actively discussed in scientific circles.
Early evidence of dog domestication that exists include rock paintings, dog footprints alongside human footprints, and bone markings from butchering. Although the first dogs usually played the role of helpers in the hunt, they were sometimes eaten, and the skins and bones were used in everyday life.
The domestication of dogs could be facilitated not only by humans - perhaps they themselves began to look for a new ecological niche and "self-domestication" took place. In addition, domestication may have had multiple foci throughout the world at different times.
It is also possible that the divergence of dogs and wolves was not due to domestication, but even before it, and to some extent contributed to the "friendship" of a dog with a person. Genetic data show that the common ancestor of dogs split from the ancestor of wolves about 135 thousand years ago.
From an anthropological point of view, data on the domestication of dogs are important for understanding the cognitive abilities and behaviors of the first Homo sapiens.
Researchers compared the jaws of ancient wolves and protops about 28, 5 thousand years old to find out if their feeding behavior somehow differed.
As it turned out, there are more pronounced signs of wear on the teeth of dogs. This shows that they ate solid food that needed to be gnawed.
There are much fewer such marks on wolf teeth. Their diet consisted of soft foods - animal flesh, as shown by earlier studies - mostly mammoths.
This difference in nutrition suggests that proto-dogs gnawed on bones and other food debris that humans left behind, while wolves predominantly hunted.
This is consistent with the existing evidence for the domestication of dogs in those years.
“Our main goal was to test, based on the condition of the teeth, whether dogs and wolves had noticeable differences in behavior,” says Ungar. - Tooth surface is a behavioral indicator that can appear many generations before changes become noticeable in a population. This approach has great prospects in archaeological research, when it is necessary to distinguish protodogs from wolves."
Earlier, British experts suggested that the "puppy look" in dogs developed precisely in the process of domestication - rounded eyes with raised eyebrows increased the chances of getting a piece of meat or some other pleasant bonus. Wolves are not capable of such facial expressions.
“The movement of the muscles in the inner part of the eyebrow makes a dog's eyes look large, like those of children. Also, the expression on the face becomes similar to the expression on the face of a person who is sad,”explained evolutionary psychologist Bridget Waller.
Mutual eye contact between the dog and the owner promotes the release of oxytocin in both, which is not the case with wolves. At the same time, the muscles that dogs use to lift their eyebrows are practically undeveloped in wolves.
Muscle anatomy is changing extremely slowly, the researchers note, so the changes that have occurred can be considered quite significant.
Obviously, they helped build relationships between ancient dogs and humans.
Interestingly, the Siberian Husky, one of the oldest breeds, which is closer to wolves than many others, did not have a developed muscle in dogs that lifts the outer corner of the eye to the ear.