Power
You feed and train animals that most people consider wild, unpredictable killing machines. You have the keys to the cages and access to the aquariums, even when the zoo is closed. Audiences turn to putty when you explain the eating habits of marsupials. And let's not even talk about what happens when you're in the gorilla cage, giving a belly-rub to an 800-pound bundle of love and muscle.
Yes, the power of a zookeeper revolves around their abilities with animals—and the fact that this seems like a superpower to most people. It isn't all fun and games, but to many people it'll seem that way. You may look at your job and just see a lot of fecal matter, but the average person sees a wonderland of possibility, one in which you get to play with incredible creatures from every part of the world.
And besides caring for the sick and feeding the hungry, you also have the ability to speak for these animals. Endangered species are a real thing, and so are the conservationists fighting to spread awareness and help non-humans remain a part of the beauty of planet Earth. You can be a powerful voice in that fight.