Native to Australia, the platypus is an aquatic mammal that eats a variety of small animals including crayfish, earth worms, frogs, and small fish. The male platypus has a pair of venom producing spurs on its hind legs that serve as protection. These spurs can cause agonizing pain to humans and have been reported to kill dogs. The platypus is one of only two mammals in the world that lays eggs as opposed to giving birth to live young.