The Platypus is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. Together with the four species of echidna, it is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young.
It is one of the few venomous mammals; the male Platypus has a spur on the hind foot that delivers a venom capable of causing severe pain to humans. The unique features of the Platypus make it an important subject in the study of evolutionary biology and a recognisable and iconic symbol of Australia; it has appeared as a mascot at national events and is featured on the reverse of the Australian 20 cent coin. The Platypus is the animal emblem of the state of New South Wales.
The Platypus is semi-aquatic, inhabiting small streams and rivers over an extensive range from the cold highlands of Tasmania and the Australian Alps to the tropical rainforests of coastal Queensland as far north as the base of the Cape York Peninsula. Inland, its distribution is not well known: it is extinct in South Australia (apart from an introduced population on Kangaroo Island) and is no longer found in the main part of the Murray Darling Basin, possibly due to the declining water quality brought about by extensive land clearing and irrigation schemes. Along the coastal river systems, its distribution is unpredictable; it appears to be absent from some relatively healthy rivers, and yet maintains a presence in others that are quite degraded (the lower Maribyrnong, for example).
We are aware of the existence of viewing platforms for the observation of Platypuses in their natural habitat at the following locations: Chambers Wildlife Rainforest Lodge, Qld; Petersen Creek viewing area, Yungaburra, Qld; Malanda Falls Environmental Park, Qld; Broken River picnic grounds, Eungella National Park, Qld; Ravenshoe, Qld; Toorourrong Reservoir, Whittlesea, Vic; Uki, NSW; Yabbra NP, NSW; Bombala Platypus Reserve, Bombala, NSW; Flinders Chase NP, Kangaroo Isld, SA; Warrawong Earth Sanctuary, SA
Platypus are widely kept for display purposes by zoos and wildlife sanctuaries across Australia. They are generally on display in specially built indoor platypussary – a simulated stream in a tank – that illustrate life around creek beds.
Much of the world was introduced to the Platypus in 1939 when National Geographic Magazine published an article on the Platypus and the efforts to study and raise it in captivity. The latter is a difficult task, and only a few young have been successfully raised since – notably at Healesville Sanctuary in Victoria. The leading figure in these efforts was David Fleay, who established a platypussary at the Healesville Sanctuary, where breeding was successful in 1943. In 1972, he found a dead baby of about 50 days old, which had presumably been born in captivity, at his wildlife park at Burleigh Heads on the Gold Coast, Queensland. Healesville repeated its success in 1998 and again in 2000 with a similar stream tank. Taronga Zoo in Sydney bred twins in 2003, and breeding was again successful there in 2006. There is an excellent Platypus House at Beauty Point in northern Tasmania.
The geographic range of Ornithorhynchus anatinus is restricted to the wetter regions of eastern Australia and Tasmania.
Duck-billed platypuses inhabit rivers, lagoons, and streams. They prefer areas with steep banks that contain roots, overhanging vegetation, reeds, and logs. The rivers and streams are usually less than 5 meters in depth. There have been records of them living in aquatic habitats at elevations above 1000 meters.
Duck-billed platypuses are one of three species of monotremes. These species are unique among mammals in that they retain the ancestral characteristic of egg laying. They have a cloaca through which eggs are laid and both liquid and solid waste is eliminated. Duck-billed platypuses are stream-lined and elongated, they have fur ranging from medium brown to dark brown on the dorsal side and brown to silver-gray on the ventral side. They have bills that closely resemble those of ducks, and flat and broad tails resembling those of beavers. Two nostrils are located on top of their bills and their eyes and ears are on either side of their heads.
They have short limbs, naked soles, webbed forefeet and partially-webbed hind feet. Each foot contains five digits each consisting of a broad nail for the forefeet and sharp claws for the hind feet. Males are generally larger than females, and have two venom glands attached to spurs on their hind legs. Females have mammary glands but no nipples. The young have milk teeth while the adults have grinding plates.
Duck-billed platypuses are one of the three mammal species that lay eggs. There is little available information on breeding, estimated gestation periods are 27 days and incubation periods are 10 days. Lactation lasts three to four months. Most juvenile females do not begin to breed until they are four years old. Female duck-billed platypuses build burrows in which to protect and nurse their young. During the incubation period, the female platypus will incubate eggs by pressing the egg to her belly with her tail. The incubation period usually lasts for 6 to 10 days. Duck-billed platypuses generally lay two to three eggs. Duck-billed platypuses are solitary, especially males. If the territories of males overlap, they change their foraging time to avoid each other.
Except for its loss from the state of South Australia, the Platypus occupies the same general distribution as it did prior to European settlement of Australia. However, local changes and fragmentation of distribution due to human modification of its habitat have been noted. Duck-billed platypuses are currently protected by the Australian government. Their skins were once harvested by fur traders to make hats, slippers, and rugs. Harvesting was ended by a law passed in 1912 that protected platypuses from being hunted. Predators of duck-billed platypuses include foxes, humans, and dogs. Others are snakes, birds of prey, feral cats, and large eels.