The oncilla in the south of Brazil currently mates with Geoffroy’s cat (L. geoffroyi) creating a hybrid, while the oncilla in the northeast of Brazil in ancient times mated with the pampas cat (L. colocolo)¹. Currently there is a relatively small overlap in the distributions of the oncilla and Geoffroy’s cat. The southern oncillas don’t mix with the northern ones and for this reason it is said that there should be two species of oncilla.
Tigrina mates with Geoffroy’s cat
Also, the hybrid offspring mate with the original “purebred” species that created them. This is backcrossing and is called “introgression”. So, for example the offspring of an oncilla and Geoffroy’s cat might mate with a Geoffroy’s cat.
This is interesting because one of the criticisms of captive tigers is that they are often “generic” meaning they are neither Siberian tigers nor Bengal tigers. They are not purebred. Well, we can now say that a lot of oncillas in the wild are not purebred either. The same can be said of the Scottish wildcat, which mates with local feral and stray domestic cats creating the “Kellas Cat” a hybrid. There are quite possibly no purebred Scottish wildcats left.
So, is a “purebred” wild cat species important? No, seems to be the answer. It is natural for some species of the same genus (a group of species that are similar) to mate with each. It probably improves the species. It certainly should help offset problems of inbreeding if the population is isolated or small.
The scientific name for the oncilla is Leopardus tigrinus. The name oncilla is often used but there are many other names, confusingly, and the one used in the latest study that revealed this large scale hybridization is “tigrina”.
I am surprised that the experts have suggested that because the tigrinas in the south don’t mate with the tigrinas in the north that they should be considered different species. I have seen no information to suggest that they are different at the DNA level. Perhaps I have missed something.
Note: (1) Current Biology.
However, the tamed wildcat is actually a different subspecies (F S lybica) from the Scottish Wildcat (F s grampia). Left alone, the two would probably have speciated fully.
I have a problem with the idea of “non-native species” and human intervention. It can be used as an excuse to eradicate a species. The Australian government’s attitude towards the feral cat is the best example.
The difference in the case of tiger species (Amur/Bengal) is that they don’t meet and hybridise naturally (geographical barriers) so they are moving towards speciation. In the case of oncillas/pampas cats/Geoffroy’s cat the hybridisation occurs without 2 separate (sub)species being put into a cage together with no mate choice.
With the South American cats they are overlapping species, like a chain (http://en.wikipedia.org/wiki/Ring_species). For some reason (habitat loss? population loss?) the link between the two oncilla populations has been broken and they no longer interbreed. With tigers, they have already become distinct and non-overlapping populations. With Kellas cats, the introgression is due to the introduction of a non-native felid – interbreeding would not have occurred without human intervention (the same as with tigers).
Species is largely a human construct. Nature is more thrifty with genes. Species can both diverge and merge according to environmental conditions (this is seen in action with Galapagos finches – they diverge into specialists when food is abundant, but merge into generalists after major climate events that deplete plant species, then re-diversify when the plants recover). Polar/Grizzly bear hybridisation is another example of 2 geographically overlapping species REcombining as the environment changes (these 2 species came from the same single species).
The key to whether it matters, is whether the species overlap and interbreed naturally to form fertile hybrid populations, or whether it requires human intervention to make it happen.
Thanks Sarah for a great comment. For me, you make subtle points. For example, the Scottish wildcat interbreeding with the domestic cat would not have happened but for human intervention. Agreed of course.
But humans are a species of animal and the wildcat decided to befriend the human 9,500 years ago. Then the human brought the tamed wildcat to Scotland (2,000 years ago).
The whole process seems very natural to me and to talk of human intervention seems a little artificial sometimes.
The evolution of the Scottish wildcat was a natural process arguably and not really about “intervention”.
Species are a human construct. Cat breeds are even more of a human construct. Taxonomy is constantly in flux and unsettled and the classifications are disputable. This also makes things less black and white and more grey.