|From Top: dog, hybrid pup, wolf|
And these crosses are not necessarily ancient or historical; two to three percent of the sampled wolves and dogs were identified as first-generation hybrids.
The study was undertaken as part of work exploring human-wolf conflict in Georgia. In the last decade or so, the frequency of wolf predation on cattle has increased in Georgia, and there have even been several reported attacks on humans and sightings of wolves in densely populated areas. One theory was that the attacks might not be coming from pure wild wolves, but from wolf-dog hybrids who have less fear of humans. Now, a first cut at the genetic evidence suggests that line of thinking may have legs.
As I have noted in the past, the differences between wolves, dogs, Coyotes, and Golden Jackals are so slight that they can ALL interbreed and produce fertile young (see pictures here).
This is not to say dogs, Coyotes, Golden Jackals, and wolves are not different.
Wolves and coyotes howl and almost never bark, while dogs bark and almost never howl.
Male and female alpha wolves lift their legs to pee, while all other wolf pack members squat to pee. With dogs, almost all males lift their legs, and almost all females squat.
With wolves, estrus occurs only once a year in January or February, while with most non-primitive dogs, estrus occurs twice a year, and can occur at any time.
There are other differences too -- physical differences. Wolves have a pre-caudal gland while dogs do not, and there is also a very small bone difference in the feet of one wolf sub-species.
The world of canids is one in which speciation is occurring and has not yet fully occurred. It is still a process, not an event.
And it is a process in which man is still very much stirring the pot.
In Alaska, Kazakhstan, Spain and Romania, there are still wolf pups being snatched from the wild and raised as dogs. These animals are so unreliable as pets that there are laws in almost every country prohibiting their ownership, but their ownership is so common that there's also a entire lexicon of language where the dogs are described as "Malamutes." In fact, many of the animals bought as wolves are Malamutes! Such is the plastic nature of dogs and wolves.
In Italy, Alaska, Minnesota, Spain, Ethiopia and the Middle East, wolves are occasionally crossing with dogs to create small unstable hybrids with the result being mostly wolf, but with sizable doses of dog coursing through the bloodstream.
Here in the U.S. no one knows what to make of the giant coyotes that have appeared in New York and Maine. They appear to be mostly wolf, but there's a little dog in there too.