Platypus Facts

The platypus (Ornithorhynchus anatinus) is an unusual mammal. In fact, when its discovery was first reported in 1798, British scientists thought the creature was a hoax made by stitching together parts of other animals. The platypus has webbed feet, a bill like a duck, lays eggs, and males have venomous spurs.

The plural form of "platypus" is a matter of some dispute. Scientists typically use "platypuses" or "platypus." Many people use "platypi." Technically, the proper Greek plural is "platypodes."

Description

The platypus has a keratin bill, a broad flattened tail, and webbed feet. Its dense, waterproof fur is dark brown, becoming paler around its eyes and on its belly. The male has one venomous spur on each hind limb.

Males are larger than females, but size and weight varies considerably from one individual to another. The average male is 20 inches in length, while females are around 17 inches long. Adults weigh anywhere from 1.5 to 5.3 pounds.

Habitat and Distribution

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The platypus lives along streams and rivers in eastern Australia, including Tasmania. It is extinct in South Australia, except for an introduced population on Kangaroo Island. Platypuses live in diverse climates, ranging from tropical rainforests to cold mountains.

Diet and Behavior

Platypuses are carnivores. They hunt worms, shrimp, insect larvae, and crayfish at dawn, dusk, and night. The platypus closes its eyes, ears, and nose when it dives and moves its bill from side to side, much like a hammerhead shark. It relies on a combination of mechanosensors and electrosensors in its bill to map its surroundings. The mechanosensors detect touch and movement, while the electrosensors sense tiny electrical charges released by muscle contractions in living organisms. The only other mammal to use electroreception to seek prey is a species of dolphin.

Reproduction and Offspring

Except for the echidna and platypus, mammals give birth to live young. Echidnas and platypuses are monotremes, which lay eggs.

The platypus mates once each year during the breeding season, which occurs between June and October. Normally, a platypus lives a solitary life in a burrow above the water level. After mating, the male departs for his own burrow, while the female digs a deeper burrow with plugs to control environmental conditions and protect her eggs and young. She lines her nest with leaves and grass and lays between one and three eggs (usually two). The eggs are small (under half an inch) and leathery. She curls around her eggs to incubate them.

The eggs hatch after about 10 days. The hairless, blind young drink milk released by pores in the mother's skin. The offspring nurse for about four months before emerging from the burrow. At birth, both male and female platypuses have spurs and teeth. The teeth drop out when the animals are very young. The female's spurs drop off before she is a year old.

A platypus reaches sexual maturity in its second year. In the wild, a platypus lives at least 11 years. They have been known to reach 17 years of age in captivity.

Conservation Status

The IUCN classifies the platypus conservation status as "near threatened." Researchers estimate the number of mature animals anywhere between 30,000 and 300,000, usually settling on a number around 50,000.

Threats

Although protected since 1905, platypus numbers have been decreasing. The species faces habitat disruption from irrigation, dams, and pollution. Disease is a significant factor in Tasmania. However, the most significant threat is reduced water availability from human use and droughts caused by climate change.

The Platypus and Humans

The platypus is not aggressive. While its sting may be fatal to smaller animals, such as dogs, there has never been a documented human fatality. The animal's venom contains defensin-like proteins (DLPs) that cause swelling and excruciating pain. Additionally, a sting results in heightened pain sensitivity that may persist for days or months.

If you want to see a living platypus, you have to travel to Australia. As of 2017, only select aquariums in Australia house the animals. The Healesville Sanctuary in Victoria and the Taronga Zoo in Sydney have successfully bred platypuses in captivity.

Sources

• Cromer, Erica. "Monotreme Reproductive Biology and Behavior". Iowa State University. April 14, 2004.
• Grant, Tom. The platypus: a unique mammal. Sydney: University of New South Wales Press, 1995. ISBN 978-0-86840-143-0.
• Groves, C.P. "Order Monotremata". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 2, 2005. ISBN 978-0-8018-8221-0.
• Moyal, Ann Mozley. Platypus: The Extraordinary Story of How a Curious Creature Baffled the World. Baltimore: The Johns Hopkins University Press, 2004. ISBN 978-0-8018-8052-0.
• Woinarski, J. & A.A Burbidge. Ornithorhynchus anatinus. The IUCN Red List of Threatened Species 2016: e.T40488A21964009. doi:10.2305/IUCN.UK.2016-1.RLTS.T40488A21964009.en