Ask Lemmy

Horse (equus ferus caballus) + donkey (equus asinus) = mule

In general, the most widely cited definition of what a species even is is a group who's members can produce fertile offspring. But there are still edge cases like ring species, where population A can mate with population B, population B can mate with population C, but A and C can't.

If you'll permit me one of my linguistics tangents, there's an analogous phenomenon called a dialect continuum, where dialect A is intelligible to speakers of dialect B, dialect B is intelligible to speakers of dialect C, but A and C are not mutually intelligible.

Humans did. There was regular crossbreeding producing hybrids between Homo sapiens and Neanderthals.

Other species can produce hybrids, but i dont know of any that do so regularly

Ligers (products of male lions and female tigers), and tigons (product of female lions and male tigers).

Male ligers are sterile, but female ones can reproduce. Same with tigons.

Plenty.

Mules are the result of donkeys and horses mating.

Ligers are the result of lions and tigers mating.

It's literally what the word "hybrid" originally meant: the offspring of two different species.

Kind of if the species are very close. The most famous example is probably mule:
https://en.wikipedia.org/wiki/Mule

That’s sort of impossible by definition.

One of the ways we have defined a species is that it can’t breed with another species, be it due to bio mechanics (the sex organs don’t match), or genetics (mismatched chromosomes etc). Humans have tried to create hybrids of closely related species like horses and donkeys, but the resulting mule is sterile. See also tiger lion hybrids etc.

Lions, panthers, leopards, pumas, tigers

https://en.wikipedia.org/wiki/Hybrid_(biology)

If it happens, they were already closely related on the species branch, and usually there are issues with their DNA and ability to reproduce themselves because of the slight differences.

Clint's reptiles talks about a wasp that there is only males and no females or vice versa. I forget. And they mate with a different species. I can't find the video right now. I'll try and get back to you.

https://en.wikipedia.org/wiki/Ring_species

What a species is and how genes flow between populations is complex and weird!

Viruses, in a sense.

Yup.

I'll run some tests and get back to you...

You'd use "individuals" in the second use of creature in this context, but short answer is yes, keeping in mind the definition of species is largely arbitrary.

There's much more that goes into the definition than reproductive ability, so for example a lot of birds that are in theory different species are fully capable of breeding with a different bird species.

Then of course there's the coywolves and coydogs. Fully fertile (as far as I know), arguably better adapted to the niche than either coyotes or wolves, they'll probably be recognized as their own species at some point.

Donkeys.