The internet is fueled by adorably unexpected mixed-species friendships. But have you ever wondered why animals we assume would be natural enemies—like dogs and cats, for instance—can be such great companions in the right conditions? As National Geographic explains in this overwhelmingly cute video about Kumbali the cheetah cub and Kago the yellow Labrador Retriever puppy, it all comes down to what they need as they develop. In Kumbali's case, Kago is at once a calming influence and a patient playmate who can focus the cat's considerable energy, meanwhile teaching him social cues. As for the pooch, well, he probably just likes everyone and everything. So there you have it: the scientific principle behind the four-legged BFFs who give us reason to log on every day.