I thought that meeting outside of the species was impossible. But it's not? What about humans?

I found out that these are hybrid animals that result from the mating of two different species!





Ligers/Tigons (lion/tiger)


Mules (horse/donkey)


Zebroid is a Zebra mix.. Zorse (horse/zebra) Zonkey (zebra/donkey)


Cama (Camel/Llama)





I thought that mating outside of the species was impossible? What can a human mate with that's not human then to produce an offspring?

I thought that meeting outside of the species was impossible. But it's not? What about humans?
This is one of the steps of separation of species. For instance, lions and tigers live on different continents and have for a very long time. Their mutual ancestor was a single species, but even with the long separation in space and time, they are still in the process of forming completely separate species. They can still interbreed, but their offspring are sterile.





Compare this with domestic cows and buffalo and also domestic cows and yaks. They are considered separated species and the separation came a long time ago. But, they really aren't as separate as the species you mentioned. Cows and buffalo can produce fertile offspring. Cows and yaks can produce fertile female offspring but not fertile male offspring.





Identifying separate species is not as clear cut as it might seem and many that have been identified as separate turn out not to be. Most of us consider wolves and dogs as separate species, but of course, they are perfectly capable of interbreeding and producing fertile offspring.





There is no known animal that humans can mate with and produce offspring. Chimps and bonobos are the closest living relative, but that was tried in Russia quite a few years ago and it didn't work. If Neaderthals were still around it is likely humans could successfully mated with them. Unknown whether that cross would have produced fertile or sterile offspring.
Reply:All of those pairs are of the same species.
Reply:They can't reproduce so they are not considered a different species. A species needs to be able to reproduce. Not one of these animals can reproduce. Humans can't mate with anything except a human. You need to be able to reproduce and contribute to the gene pool to be classified a species.
Reply:Close species can be crossed to create offspring, but offspring of the crossing of 2 species can not reproduce.





ie a lion and a tiger produce a liger, but ligers can't reproduce.
Reply:Part of your problem, and that of people answering, is the definition of species which depends on either non-reproduction or reproduction to produce sterile offspring. This holds for many living animals but not for fishes. Some minnows of different genera can hybridize to produce offspring that are not only fertile with themselves but fertile with both parent species.





Your question about humans is also difficult to answer because of how we define species. There is a great deal of emotion involved in determination of species and subspecies of humanoids. My best guess (and that is all it is) is that Cro-magnon man (Homo sapiens) interbred with Homo neanderthalensis when they weren't killing one another and that some of the traits associated with the latter persist today. So far as I know, humans cannot produce viable offspring with any animal alive today, except for other humans.
Reply:Those animals you listed are different species, but they are in the same genus or family group (lions and tigers are both in the family Felidae, for example). The more closely related the animals, the more likely you are to be able to interbreed them. Species differentiation came about in some of these animals due to reproductive isolation from one another -- tigers went to Asia and lions went to Africa, but they started out near each other before diverging.





By the way, people breed different species of dogs all the time -- a lab and a poodle for example. And those animals are usually reproductively viable (can have offspring). Also, there is actually a non-sterile mule in Mexico -- guess no one mentioned to the mule that it's not supposed to be able to breed!





As for humans, so far no one has successfully interbred anything with a human. Why would you even want to??
Reply:Some species are compatible enough to produce non fertile offspring.





However, the human genes don't match up with any other species so we can't. Our nearest relatives have a different chromosome count so we can't breed.
Reply:It is possible, but even if viable hybrids are produced (hybrids that survive), they are sterile. Another factor is that these animals would never or almost never mate under natural conditions, so there's a pre-zygotic barrier as well.
Reply:two closely related species can breed and produce a hybrid offspring, as in the examples you've mentioned. But the reply that said "people breed different species of dogs all the time -- a lab and a poodle for example." is incorrect, because the term "species" is not the same as "breed", Labradors and poodles are the same species, Canis familiaris; Shire horses and Shetland ponies are the same species, Equus caballus; they are only races or breeds of those species, and can interbreed and produce viable offspring.





Homo sapiens is a species (with lots of races!) and there isn't anything else genetically close enough to interbreed to produce a hybrid.
Reply:Humans could have probably reproduced with other human-like species in the same family, such as Neanderthal, Cro-Magnon Man, etc. But these species are all gone so we're just gonna have to stick to other humans.