Genocide is "the deliberate and systematic destruction, in whole or in part, of an ethnic, racial, religious, or national group". Animals do not commit genocide. PERIOD. A lion might kill another male to take over its pride, but it won't partner up with other lions to deliberately wipe out another group.
Skirmishes between animals are very localized and focused on "survival of the moment." There is no long term deliberation possible, which is what is required when enacting genocide.
Animals are motivated to kill their competitors. Any species that didn't become extinct as a direct result of a natural catastrophe was out-competed. That's genocide. The only difference is that when Humans act on that impulse, they can put their intellectual capacity and technology behind it. Again, it's acting on instinct rather than rationalism.