“The concept of ‘breed’ is very recent and does not apply to the archaeological record,” Evin said. People have, of course, been breeding dogs for certain traits for as long as we've had dogs, and tiny lap dogs even existed in ancient Rome. However, it is unlikely that a Neolithic shepherd would have described his dog as a separate “breed” from his neighbor's hunting partner, even if they looked completely different. Which, apparently, they did.
By the Neolithic era, dogs had about half their modern diversity (at least in skull shape and size).
Credit: Kiona Smith
The bones only tell part of the story
“We know from genetic models that domestication must have begun in the late Pleistocene,” Evin told Ars. A 2021 study proposed that domestic dogs have been a separate species from wolves for over 23,000 years. But it took time for differences to accumulate.
Evin and her colleagues had access to 17 canine skulls ranging in age from 12,700 to 50,000 years old (before the end of the Ice Age) and all of them were so similar to modern wolves that, according to Evin, “at this point we have no evidence that any of the wolf skulls were not from or different from wolves.” In other words, if you just look at the skull, it's hard to tell the earliest dogs from wild wolves.
Of course, we have no way of knowing what a living dog might have looked like. It's worth noting that Evin and her colleagues found the skull of a modern St. Bernard, which, according to their statistical analysis, more closely resembled a wolf than a dog. But even if he doesn't offer you a keg of brandy, a live St. Bernard with his slack jaw and floppy ears cannot be mistaken for a wolf.
“The shape of the skull tells us a lot about function and evolutionary history, but it represents only one aspect of the animal's appearance. This means that two dogs with very similar skulls could look very different in life,” Evin told Ars. “This is an important reminder that the archaeological record reflects only part of biological and cultural history.”
And if we continue only with bones, and rare ones at that, we may miss some of the early chapters of the biological and cultural history of dogs. Domestication tends to select the friendliest animals to produce the next generation, and obviously this comes with a certain set of evolutionary side effects, whether you're studying wolves, foxes, cattle or pigs. The spots, floppy ears and curved tails appear to be part of a genetic package that promotes interspecific friendliness. But none of these features are visible in the skull.
