platypus

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platypus

(plăt`əpəs), semiaquatic egg-laying mammal, Ornithorhynchus anatinus, of Tasmania and E Australia. Also called duckbill, or duckbilled platypus, it belongs to the order Monotremata (see monotrememonotreme
, name for members of the primitive mammalian order Monotremata, found in Australia, Tasmania, and New Guinea. The only members of this order are the platypus, or duckbilled platypus, and the several species of echidna, or spiny anteater.
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), the most primitive group of living mammals. The only other member of this group is the echidnaechidna
or spiny anteater,
animal of the order Monotremata, the egg-laying mammals. A short-legged, grayish brown animal, the echidna is covered with sharp quills and can protect itself by rolling into a tight bristly ball. It may reach 18 in. (46 cm) in length.
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, or spiny anteater.

The head, trunk, and tail of the platypus are broad and flattened and covered with thick dark brown fur. The muzzle is shaped like a duck's bill and is soft and rubbery. It contains ridges used for crushing food; the animal has no teeth. The eyes are small and there are no external ears. The five-toed feet are webbed. The heel of the adult male bears a hollow spur connected to a venom-secreting gland. This spur is probably used as a weapon, but its use is unclear; the males only produce venom during the breeding season. Females lose their spurs at about one year of age. The adult male platypus is about 2 ft (60 cm) long, including the 5 or 6 in. (13–15 cm) tail; it weighs about 4 lb. The female is slightly smaller.

The platypus is found from tropical swamps at sea level to cold lakes at altitudes of 6,000 ft (1,830 m). Its diet consists entirely of small freshwater animals dredged from muddy bottoms. Prey captured underwater are stored in cheek pouches and eaten at the surface or on land.

Platypuses live in pairs in simple burrows in stream banks, except during the breeding season, when the female makes a separate and more elaborate burrow containing a nesting chamber approached by a long tunnel. One, two, or three eggs are laid at a time and are incubated, in birdlike fashion, by the female. The female lacks nipples, and the young lick milk from the fur around the many small abdominal openings of the mammary glands. The platypus is classified in the phylum ChordataChordata
, phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate animals.
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, subphylum Vertebrata, class Mammalia, order Monotremata, family Ornithorhynchidae.

Platypus

 

(also duckbill; Ornithorhynchus anatinus), the only representative of the family Ornithorhynchidae, subclass Monotremata. The body measures 30–45 cm in length, and the tail 10–15 cm; the weight varies from 0.5 to 2 kg. The body is terete, low, and covered with a thick, soft pelt that is brown on the upper parts and grayish on the underparts. The anterior part of the muzzle is drawn out into a flat bill, which is covered with a soft, naked skin. The tail is flattened and covered with fur. The feet are webbed, and the front ones have strong claws. The animal lacks teeth and a brood pouch.

Distributed in eastern Australia and Tasmania, the platypus inhabits the banks of bodies of water and leads a semiaquatic way of life. It is active at twilight and lives in a burrow measuring as much as 10 m in length. The animal feeds on invertebrates. It reproduces in August and September. The female lays one or two eggs, which she incubates in the burrow for nine or ten days. The young take four months to develop. The platypus was once hunted for its valuable fur but is now protected by law.

O. L. ROSSOLIMO

platypus

[′plad·ə‚pu̇s]
(vertebrate zoology)
Ornithorhynchus anatinus. A monotreme, making up the family Ornithorhynchidae, which lays and incubates eggs in a manner similar to birds, and retains some reptilian characters; the female lacks a marsupium. Also known as duckbill platypus.