I recently looked through a book called “The Encyclopedia of Dogs,” which started out on the evolution of canines and, of course, the evolution of the dog from the wolf. Now, I know that since dogs and wolves are capable of breeding with each other and producing offspring that can breed, they’re now considered members of the same species. I assume that this book was a bit older than its condition suggested, though, since dogs were still classified as a different species in it.
But, then, something really caught my eye. There’s a reference to coyotes and jackals being able to interbreed with Canis lupus. Living in the Nevada desert, I have heard about coyotes and dogs (the ones that aren’t so small as to make a nice meal anyway) breeding together, but have never heard much about what the offspring are like. And, I had never heard of jackals breeding with anything except for, well, other jackals. I assumed they were much more distantly related.
But, a little research shows that yes, coyotes and jackals are able to breed well enough with dogs to suggest that they descended from them as well as wolves, at least in the opinion of some scientists. So, now I’m lost. Just how close are these animals? Should they really be considered part of one large species?
I admit up front that this may not be 100% correct, but I beleive the definition of “species” now includes not only whether an animal is genetically capable of interbreeding with another, but also whether they would normally do so under natural conditions and whether their union would produce fertile offspring. For instance, lions and tigers can interbreed, but their habits and habitats are so different theat they would never do so in the wild. Therefore, they are still considered different species.
I seem to remember seeing somewhere that jackels have one more set of chromosomes than wolves and dogs. I wonder if their crossbred offspring would be sterile, like mules and hinnies.
IIRC, wolves, coyotes and jackals are all capable of producing viable offspring (not sterile) by mating with domestic dogs. All four groups are in the genus canis.
The domestic dog is most closely related to the grey wolf (about 0.2% genetic difference). This is compared to about a 4.0% difference from coyotes. Essentially, the domestic dog is a grey wolf.
Dogs used to be considered a separate species, canis familiaris. Now they are considered a subspecies of wolf, canis lupus familiaris. Initially, it was thought that dogs had arisen from jackals, but the genetics don’t support it.
Foxes, bushdogs, African wild dogs, and South American wolves are not in genus canis and, as far as I know, cannot interbreed viably (maybe not at all) with domestic dogs.
Incidentally, hyenas, though doglike, are a whole different family, more closely related to cats and mongooses than dogs and wolves.
If you have a cite, Scupper, for your info I’d like to see it. Not that I’m skeptical, I’d just like to know more. I have a fairly recent book that states that jackals are part (but only part) of the domestic dog’s heritage – it even goes so far as to suggest that different breeds may have different heritages. As you point out, genetic data can clear a lot of this up but I haven’t seen any. (Not that I’ve looked all that hard.)
Along the same lines I have heard speculation that the red wolf may be nothing more than a cross between a grey wolf and a coyote, and not a separate species at all.
Finally, anyone who claims to have a definitive definition (get it?) for a species is either confused or lying. No single definition of the term is univerally accepted, even among (or perhaps especially among) biologists. It is similar to the definition of a language vs. a dialect – where does one leave off and another begin? When is a species a distinct species and when is it a subspecies or some other relation? The OP is a good example of where trying to define the terms too closely can get in the way of understanding. (See George Lakoff’s Women, Fire, and Dangerous Things.)
My impression is also that the “no-interbreeding-between-species” division is not absolute, but just one of the generalizations (one of the many factors) used to distinguish between species.
There’s the question of whether it’s possible at all vs. whether their behavior would result in interbreeding.
One example…I think mallards and black ducks are still considered separate species, even though it’s common for them to interbreed.
BTW the author notes at one point that some animals labeled “wolf” are not technically wolves, and some animals labeled “jackal” are more properly called wolves.
Caught me out on that one. Shouldn’t have ventured an answer off the top of my head. I actually did mean to state that there is no universally agreed on definition of “species”. I understand some biologists consider it so inexact as to be virtually useless. The definition I mentioned is only one of many being bounced around. I’ll probably go home and find out I was hallucinating about the jackal chromosomes, too.