Have you ever looked into a fish tank and just watched the fish? They just kind of... hover. They don't have eyelids. They don't curl up in a little bed. So it leads to a really common question: do fish even sleep? We see our dogs and cats do it, and we know we need to do it. But what about all the other animals? The world of animal sleep is so much more fascinating and, honestly, weirder than you might imagine. It’s full of incredible survival strategies and abilities that sound like science fiction.