I recall from high school we were given the definition of species as a group of organisms that could breed and produce fertile offspring. Somebody mentioned that a horse and a donkey could produce a mule, but the teacher mentioned mules are infertile. However, I have heard of wolves and dogs producing offspring that were fertile. I have also heard of certain breeds of dogs (such as huskies) having wolf bred into them. Is this true? I know dogs (Canis familiaris) and wolves (I believe Canis lupis) are of differing species. Have I been lied to about dogs and wolves mating, or is there a flaw in the definition of species? And what about different species along an evolutionary chain, like Homo sapiens and Homo erectus? How could scientists possibly know we couldn’t mate with our ancestors and produce fertile offspring? (Okay, this did end up involving humans, but not in a beastiality way.)
This is no longer considered a full definition. It is more that a species are a group of organisms that as a rule don’t interbreed in the wild. There is also the situation of Ring Species, which get more complicated.
Current thought is that wolves and dogs are essentially the same species. There’s very little difference between a Peekenese and a Wolf.
Not lied to (dogs and wolves interbreed easily) but definitions have changed over time. As to the past, without DNA evidence that would rule it out, it’s pretty much impossible to know for sure.
Cool. So the definition I was given was flawed. That pretty much answers my questions. Thanks.
“There’s very little difference between a Peekenese and a Wolf.”
Wolves everywhere hang their heads in shame.
Or drag Peeks into the alley behind the bar and beat the snot out of them.
Your teacher was not completely accurate on this one, too.
By far most horse-donkey crosses (mules, hinnys*) are infertile, but not all. There have been about a hundred verified live foal births to mule mollies in the last century. (Possibly many more non-verified – mules are more common in poorer countries, where such breeding records are not a high priority.)
Mules of both sexes posess fully developed, functional sex organs; and mollies go into heat just like mares or jennys. And john mules are fully capable of mounting a mare just like a stallion. But such breedings only rarely seem to produce foals. The current theory is that the chromosomes in their DNA do not quite pair up completely, except in a few rare cases. So they are mostly infertile.
It’s an open question whether either horses or mules could cross-breed with the other equine species, the zebra. There’s never been a recorded offspring. But then, the species don’t mingle much in the wild (territories don’t overlap), and there hasn’t been much desire for humans to attempt cross-breeding. (The zebra traits are much less desirable to humans than either the horse or mule, particularily the disposition. Nobody seems to have thought it worth the effort to try crossing them.)
- Male donkey (jack, jackass) + female horse (mare) = mule
Male horse (stallion) + female donkey (jennet, jenny) = hinny
Well, that’s news to me. I guess that question is no longer open.
That’s not the first. Oaklawn Farm Zoo here in Nova Scotia had a zonkey last time I checked (sorry, no link, I looked but apparently they don’t have a website), and that was definately before 2001.