platypus

When the platypus was discovered 200 years ago, scientists thought the first specimens were fakes. It has some birdlike features, such as the duck's beak and webbed feet; it also lays eggs. The body has some reptilian characteristics, but is covered with hair like a mammal. Like a mammal, the platypus feeds its young with milk.

Monotreme, or egg-laying, mammal Ornithorhynchus anatinus, found in Tasmania and eastern Australia. Semiaquatic, it has small eyes and no external ears, and jaws resembling a duck's beak. It lives in long burrows along river banks, where it lays two eggs in a rough nest. It feeds on water worms and insects, and when full-grown is 60 cm/2 ft long.

Platypuses locate their prey by detecting the small electric fields produced by their nerve and muscle activity. Males have sharp venomous spurs on their hind legs that they use for defence. The spurs administer (by way of a kick) a cocktail of at least four different toxins that cause intense pain that may last for several weeks.

US researchers into REM sleep showed 1998 that platypuses experiences more REM (dream) sleep than any other animal. It had previously been thought that dreaming had evolved only in placental mammals.