The male platypus has venomous spurs on its hind legs.
Male platypuses possess hollow, sharp spurs connected to venom glands on their hind limbs. The venom is most potent during the breeding season and is mainly used in competition between males. It can cause severe pain and swelling in humans, although it is not usually fatal.
The platypus is a monotreme, meaning it is one of the few mammals that lay eggs rather than give birth to live young. It also has a duck-like bill, webbed feet and electroreception, which helps it detect prey underwater.
A common mistake is to assume both sexes have dangerous venom spurs. Females may develop small spurs when young, but these are lost before adulthood. The platypus is found in freshwater habitats in eastern Australia and Tasmania.