Platypus(Ornithorhynchus anatinus)
Also known as the duck-billed
platypus, boondaburra, mallangong or tambreet (Indigenous terms around Yas,
Murrumbidgee and Tumat), or tohunbuck (Goomburra language, Darling Downs).
The platypus belongs to the order
Monotremata, meaning 'one hole' because it has a single opening for its
excretory and reproductive systems. The first white Australian record of a
platypus was recorded in 1797; the British Museum still owns the original dried
specimen it received in 1799 (which shows scissor marks where the curator
attempted to prove the specimen was a hoax).
The platypus occurs only in
Australia though similar fossils from 60 million years ago have been found in
South America. Platypus populations occur throughout Tasmania, and up the east
coast of Victoria, NSW and Queensland as far as Cooktown. The platypus is now
extinct in South Australia, though Kangaroo Island has a reintroduced
population.
The platypus is the only member of
the genus Ornithorynchus.
Description
The platypus is one of the most
easily identifiable animals in the world.
- Duck-like bill, broad flat tail and thick waterproof fur
- Webbed front feet, partially webbed hind feet
- Deep brown fur on its back and top of head, golden or silky grey underneath
- No external ear structure
- Females average around 900g and measure 43cm long; males average 1.7kg and measure 50cm long (average size increases the further south the animal is found)
- The male has bony spurs on both hind legs for defence. These spurs are connected to a venom-producing gland in the thigh.
Signs
- Concentric rings appear on surface of the water when platypus dive and when they feed on the surface.
- A trail of bubbles shows their progress underwater.
- A characteristic ‘bow-wave’ when swimming on the water surface
- Burrow entrances in banks are typically 10–15cm in diameter. The burrow entrance maybe beneath the water surface or more commonly from 5cm to 1m above the water level and often hidden by overhanging vegetation
- Well-worn slide mark from the burrow directly into the water.
- Characteristic footprints sometimes left in the soft mud on the river bank, especially near a burrow
All you may ever spot of a platypus is its bow-wave. Habitat
- Freshwater streams, lakes or rivers, including artificial dams
- Alpine to tropical are
Ecology
Life history
- 12 years average life span in the wild
- 15–over 20 years in captivity.
Breeding
The platypus (and echidna) are unique mammals because they lay eggs and feed their young through milk-producing spongy glands.- Breeding season varies with location: recorded as mating in August in Queensland and October in Tasmania
- Females first mate aged 2 years, some wait until they are 5.
- 1 litter in Spring of 1–2 eggs (may not reproduce every year)
- Incubation period 10–11 days during which the female holds them against her belly with her tail
- Newborn platypus are around 1.5cm long, are
weaned at 4–5 months and remain in the burrow until they reach about 80
per cent of adult weight at about 6 months.
Food
- Carnivorous diet of fish eggs, worms, insects, crustaceans, molluscs, and tadpoles, plus larvae of caddisflies, mayflies, two-winged flies and shrimps.
- Feed almost totally in the water and mainly on bottom-dwelling prey.
- Feed mostly in the early morning and evening
- Closes its eyes and ears when diving for food but receives information through the bill that navigates and locates prey in the water.
- The bill contains two types of electroreceptors: one type senses touch , the other senses electric currents produced by the muscle contractions of prey.
- Foraging platypuses stay under water for up to one minute. All food is eaten on the surface.
The bill contains both touch sensitive and electric current sensitive electroreceptors to allow it to hunt for food.
Behaviour
- Males fight over females in the mating season, using their venomous spurs on rear legs as weapons.
- Territorial and solitary, platypus do not live in social groups. Males are not involved in raising young.
- Platypus have been known to migrate across paddocks and similar land to reach new home waterways.
Home range
- Home range is normally 2.5ha, but can be up to 15ha.
- Generally travels upto 1km along a stream but can travel up to 7km.
Distribution
- Found in waterways all along the eastern edge of Australia, from Tasmania to the Arran River near Cooktown. Wildlife Queensland research suggests that in Queensland this is not one continuous population, but at least three discontinuous populations.
- Range does not extend much past the Great Dividing Range in most areas but as far west as western Victoria.
Platypus Distribution in Australia
Threats
- Human impact on habitat and food sources:
- Waterways are under threat from dam construction, river bank erosion, irrigation, chemical pollution and garbage.
- Platypus are vulnerable to being caught in fish nets and traps as well as occasionally on fishing lines baited with worms.
- Foxes and cats
- Loss of habitat makes isolated populations more vulnerable to decreased genetic diversity.
- Climate change causing drought and loss of habitat
Conservation
Status
Platypus are protected by law. They are generally regarded as common by government environment agencies.
Platypus facts.
Until the early 20th century the platypus was hunted for its fur: 40 pelts made a cape. The platypus is one of the few venomous mammals, the spur on the hind foot delivers a poison capable of causing severe pain to humans.
Platypus are big eaters and have been recorded consuming the equivalent of 15–30 per cent of their total body weight in a day
