The platypus is the Australian mammal whose males possess a poisonous ankle spur.
Male platypuses have a sharp spur on each hind leg connected to venom glands. The venom is not normally fatal to humans, but it can cause intense pain and swelling. The spurs are especially important during interactions between males.
The platypus has several unusual features: it lays eggs, has a duck-like bill, and detects electrical signals from prey underwater. It feeds on aquatic invertebrates, small fish and other creatures in streams and rivers.
Platypuses live in eastern Australia, including Tasmania. Their bodies are covered in dense waterproof fur, while their broad, webbed feet help them swim. The animal’s mixture of mammalian, reptilian and aquatic traits confused early European scientists.