Are lions and tigers part of the same species?

[de47]

Are lions and tigers part of the same species

[i_r_e_d]

They're both cats...

[alextemplet]

No. Lions are Panthera leo; tigers are Panthera tigris. They're the same genus but separate species.

[spark13579]

The definition of species is a strange one, because it's actually rather difficult to decide exactly what it means. I would say tigers and lions are definitely separate species, although if you define species by whether or not two animals are capable of breeding then they technically are not. It is the same for things like zebra and horses. If you are talking about scientific names then it would be correct to say they are in the same genus but are not the same species.

[alextemplet]

Can ligers and tigons breed? That's the usual yardstick, if they can produce offspring that can breed. Horses and donkeys, for example, can have mules, but 99% of mules are sterile. Is the same true for horses and zebras?

[spark13579]

Yeah they can breed and I think the offspring are fertile as well, so I guess they could be considered part of the same species. I don't think they would choose to breed with each other in the wild; i.e. if you had two populations living together they would probably tend to reproduce with their own kind, but then again i'm only speculating on this.

There are actually lots of things that can breed - most of the big cats, all dogs (with the exception of mechanical isolation which may occur with large size difference), and I'm sure there are much more. The mule case is interesting, can anyone explain exactly why it is fertile? It possible has something to do with chromosome numbers, but I'm not sure.

[mith]

There's many ways of defining species one of which is morphological.

[alextemplet]

Yeah, I think that's what it is; horses and donkeys have different numbers of chromosomes, and that causes mules to be sterile. Every now and then a fertile mule will be born, though.

[Khaiy]

But the offspring of lions and tigers (ligers or tigons) are not reproductively viable. The females (tigons) I believe are fertile, but the males (ligers) are sterile in virtually all cases.