It’s always fun to watch the opposing side succumb to infighting. When it comes to the War on Animals, there is still plenty of this, not only because of a food chain and all that nonsense, but because they can’t help but kill each other sometimes.
In Australia, cane toads are all over the place, or so Discovery (Channel) would have us believe. This is a bad thing for humans in most cases (like say, if you live in Australia and want to eat things produced on a farm), but aside from making a delightful squishing sound when you run over them, cane toads are helping us in another way: they are killing off crocs.
The poisonous toads, which are native to South America, are being eaten by Australia crocodiles, and the poisons then in turn kill the killers. Really, this solves two problems for us. We have fewer cane toads and fewer crocodiles. This is a win-win situation.