While we did learn in school that different species don't interbreed, that's not always the case. Different species don't typically interbreed, but there are examples where that does happen. Horse and donkey = (sterile) mule. And several years ago two different species of siamangs (a type of Asian ape) interbred and had viable offspring. The unique thing about these siamangs is that the two species had different numbers of chromosomes.
That is impressive actually. I wonder what the chromosome counts are for lions and tigers which can interbreed for make ligers (absolutely HUGE cats) and tigons?