From: "Gary Britt" 

If the paring always produces females most of whom are sterile and in rare
instance a fertile female then that doesn't meet my definition.  Something
isn't fertile if it isn't able to reproduce *its own kind*.  A herd of
female only mule's aren't really fertile in the *species* sense, because
they are unable to perpetuate their own existence by breeding with male
mules.

Gary

"Bill Lucy"  wrote in message
news:MPG.1de64e5791d70b56989732{at}news.barkto.com...
> In article , email{at}from_Gary_Britt.org says...
> > Are you trying to state that a male and female donkey can mate and
produce a
> > baby donkey?  If they can't then it shows that a horse and a mule are
> > different species.
>
> According to *your* definition, the mating of a jack donkey and a mare
> (two different species) cannot produce a viable^h^h^h^h^h^hfertile
> offspring. Although rare, the result is a mule (female always) called a
> "hinnie". And that animal is fertile. At the very least,
that makes your
> original definition of a single species unworkable.
>
> I probably should not have included the example though, because the
> rarity clouds the point. Two different species can and do interbreed,
> creating offspring which are viable and fertile. As Bob Comer implied
> (regarding poecilliidae), the differentiation from the one parent and
> the other may be slight, but it's significant enough for taxonomists,
> and I assign a lot more credibility to them than to what you or I can
> say regarding the subject.
>

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