The platypus (Ornithorhynchus anatinus) is a semiaquatic mammal endemic to eastern Australia, including Tasmania. Together with the 4 species of echidna, it is 1 of the 5 extant species of monotremes, the only mammals that lay eggs instead of giving birth. The unusual appearance of this egg-laying, duck-billed, beaver-tailed, otter-footed mammal baffled naturalists. It is one of the few venomous mammals, the male platypus has a spur on the hind foot that delivers a painful venom.
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