Think a root canal is tough? Try performing one on a tiger. Caring for animals is the ultimate medical challenge. These are patients who can't speak, are often dangerous, and represent countless unique anatomical systems. Yet zoo vets somehow manage to give specialized care to each creature they treat. We go behind the scenes at our country's largest zoos and aquariums to witness these doctors handle every imaginable emergency, from an otter with kidney stones to a Silverback Gorilla in need of an ultrasound. It's all in a day's work.