Monotreme

Monotreme, common name applied to a group of egg-laying mammals, including the platypus, or duckbill, and the echidnas, or spiny anteaters. Monotremes are native to Australia, Tasmania, and New Guinea. They possess true teeth only during the early stages of embryonic development. After monotreme eggs are hatched, the young are helpless and, in the case of the echidna, are carried in shallow abdominal pouches. Young monotremes do not have mouth parts suitable for suckling; the liquid produced by the nippleless mammary organ is licked from the belly hair of the mother. The adult male platypus has a fighting spur on each ankle, which secretes a poisonous substance.

Scientific classification: Monotremes belong to the subclass Monotremata. The platypus makes up the family Ornithorynchidae. It is classified as Ornithorhynchus anatinus. Echidnas are classified in the genera Tachyglossus and Zaglossus of the family Tachyglossidae.