(Ornithorhynchus anatinus)


Platypus and echidna are the only egg-laying mammals in the world - called monotremes (this word means 'one holed' referring to the fact that their urinary tract, anus and reproductive tract are all in one)

Platypus are readily identified by their streamlined body, webbed feet, broad tail and characteristic muzzle or bill which is soft and pliable. An adult platypus is from 45 cm to 60 cm in length and may weigh up to 2.7 kg, with females generally smaller than males. Its usual colouration is deep brown on the back and sides of the head, body and upper surfaces of the limbs. The underside is a golden colour although silky grey is not uncommon. They have two layers of fur - a dense waterproof outercoat and a grey woolly underfur to provide much needed insulation. The fur on the broad flat tail is coarse and bristly. They have a smooth swimming action together with a low body profile and no visible ears, making them easily recognisable in the water. It could only be mistaken for a water rat, but these have a long thin tail with a white tip.

The platypus is found in eastern Australia. They live alongside freshwater rivers or lakes, and create burrows for shelter and protection. They are active mainly at nighttime hours, and use their webbed feet for swimming. When swimming the platypus has its eyes shut. They swim underwater for 2 minutes, before returning to the surface for oxygen. They can however stay underwater for up to 10 minutes, though due to their natural buoyancy, they need to be underneath another object to do this.

Monotremes are the only mammals known to have the sense of electroreception: they locate their prey in part by detecting electric fields generated by muscular contractions. The platypus' electroreception is the most sensitive of any monotreme.  Platypuses feed on insect larvae, worms or other freshwater insects. They do so mainly at night, by the use of their bill. They turn up mud on the bottom of the lake or river, and with the help of their electroreceptors located on the bill, find many insects and freshwater insects. They store their findings in special pouches behind their bill, and are consumed upon returning to the surface.

The male platypus have a hollow spur about 15 milimetres in length on the inside of both hind legs. This in turn is connected to a venom gland, and the platypus uses this spur to defend itself against predators. 

The male platypus has venom strong enough to  kill a small dog, or cause excruciating pain among humans.

Since only the male platypus has this venomous spur, and the gland peaks during mating season, many suggest it is normally used in aggressive encounters between other male platypus.

Breeding occurs during spring but is generally earlier in the north of Australia than in the south. Mating takes place in the water and after 12 to 14 days, between 1 and 3 eggs are laid in a nesting burrow constructed by the female.

The eggs are laid inside burrows and are incubated between the belly and the tail of the female and hatch after 10 to 12 days. Like the echidna, the platypus lacks nipples and milk from the mammary glands oozes out through ducts at two areas on the abdomen. It is believed that the hair around these areas acts as teats that allows the young to suck the milk. By six weeks the young are furred, have their eyes open and may leave the burrow for short intervals and even enter the water. When four to five months old the young are weaned.

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