Humans have always been fascinated by animals. Love them or hate them, they usually provoke a strong reaction in people, from the Jerkass who turns to mush when confronted by a playful puppy to the tough guy who freaks out when he encounters something slithery. Most mythologies feature animals in starring roles; some belief systems feature animals as guides, oracles, or totems representing certain qualities or certain people. So of course animals are going to turn up as symbols in popular media.