At some point in the last 10,000 years, a black dog mated with a normal colored wolf in North America, and a whole new coloration was introduced to the wolves. Gregory Barsh, a geneticist at Stanford University, has traced the gene in wolves back to the k black mutation. This mutation comes from dogs, not wolves.
This black color has also been found in Italian wolves, which have been known to interbreed with dogs– a lot. In fact, Italian wolves are so interbred with dogs, that some Italian wolves have hind dewclaws, which exist only in dogs. In fact, the presence of these hind dewclaws is used to identify wolves that have dog in them.
Black color, according to Barsh, is inherited from a dominant gene. This is the exact same genetic inheritance relationship we have with most black dogs. A black lab’s color is dominant to the yellow’s. However, Barsh points out that black German shepherds inherit their color through a recessive gene to the more typical color, but this recessive black color also occurs in Tervuren and Malinois that have Tevuren in them. Because all Belgian shepherd dogs in the FCI are recognized by phenotype and not breeding, recessive black Tervs become Groenendael (Belgian sheepdogs) in the registry, while black Malinois aren’t recognized at all.
Black wolves are almost entirely linked to the North American continent. They are most common in forest regions. This area is where we have historical records of large numbers of Native Americans living with large numbers of domestic dogs. And some of them had to be black.
Interesting, black wolves were thought to be associated with the Southeastern races of wolf. In fact, the so-called red wolf was once called Canis niger (black dog) because there were so many black wolves in Florida.
Wolf and dog interbreeding had to have been more common in the past. I’ve read accounts of the early American West that suggest that wolves were very often sharing their kills with dogs and coyotes, animals that modern wolves now kill if they run into them. In Italy, dogs and wolves don’t have a lot of prey to hunt, so they both rely on garbage dumps to feed themselves. Congregating around the same food source, the dogs and wolves are also interbreeding.
It is because of this interbreeding and the continuous development of dogs from wolves over a very long period of time that dog and wolf genetics are quite difficult to tell apart. In terms of behavior and phenotype, one can easily distinguish between the two, but the genes tell the story of a close common ancestry. In fact, that is why dogs and wolves are often considered the same species.
Today, interbreeding is not that common, especially in North America. North American wolves are far more likely to kill a dog rather than breed with one. The Italian wolves are in much smaller numbers, and the typical wolf has only so many mates it can choose from in the wolf population. It makes sense that Italian wolves would mate with dogs.
This finding is quite parismonious with what we already know about the high levels of interrelatedness with wolves and dogs. I regard them as the same species, but with important differences, just as there are important differences between Arabian wolves and Arctic wolves.
Black coyotes also exist, mainly in the Eastern subspecies. This makes sense, although I’m much more willing to believe that in coyotes, the coloration came from interbreeding with wolves as they worked their way north into Canada and then moved south into the Eastern US. Barsh found that the black coyotes ultimately got their black gene from dogs, too, but my guess is it is indirectly inherited through cross-breeding with black wolves.
Mark Derr also has an article in the NY Times. And yes, we really need to think about this term species.
National Geographic has also picked up the story.