Gluon has visited that really big planet with the little bug-eyed cats and reports that the dogs and cats there pay very little attention to one another. It's an unforeseen byproduct of an experiment in weaponized dissonant sound waves. Prior to the misguided experiment, dogs and cats there behaved pretty much the same as on Earth: they despised each other. But after being bombarded with the wayward sound waves, they began to ignore each other. Instead, both species began to channel their aggressions toward members of the native equivalents of our crocodiles and alligators. While this accidental adaptation has led to harmonious relations between dogs and cats, it has also resulted in a bunch of happy and well-fed crocodilians.