Whether it's a piano-playing cat, a surprised cat, or one that's just plain adorable, some of the most-watched online videos these days feature funny felines. And it doesn't end there; cats are ubiquitous on the Internet, inspiring meme after meme, speaking their own language, and even prompting the launch of a new film festival. But the omnipresence of the cat in pop culture is not novel. Feline references date from before 2000 BC in ancient Egypt,...