The Platypus (Ornithorhynchus anatinus) is part of a family which has occupied the Australian mainland for at least 15 million years. This small amphibious animal possesses a flexible duck-like bill and has strongly webbed feet. The Platypus is the only Australian mammal that is venomous. The echidna is a relative of the Platypus.

APPEARANCE
The platypus is brown in colour and has a sleek and smooth appearance. It has a rubbery bill, and webbed feet which are also equipped with strong claws.

The Bill.
The bill of the Platypus is rubbery and sensitive, not hard like that of a duck. The platypus is sometimes called "duckbill" in spite of this. The bill contains an electro-receptor system which helps the animal to find food under water, and various pressure sensors, which probably help it hunt and navigate while underwater.

The Legs and Feet.
Whilst in the water, the Platypus will use its front limbs to propel itself. The large webs of skin on the front feet enable the platypus to do this with ease. However, on land the platypus will fold back these webs, revealing sharp claws with which it will walk or dig burrows. The hind legs of the platypus, which have a series of sharp, curved claws, are used to help steer and stabilise the animal when it is swimming. The claws are used by the animal to keep its fur clean and waterproof. The Platypus is provided with a powerful swimming and digging action by both its front and back legs. These extend horizontally from the body of the Platypus (refer to figure 1). However, they make walking on land and crossing shallow areas of water difficult, and the platypus is forced to shuffle like a lizard. It cannot move very fast and, therefore, is vulnerable to predators such as foxes and dogs.

Fur.
The body of the platypus is covered with fine, dense fur which is denser than that of river otters and polar bears. There are around 800 hairs packed together in each square millimetre. Platypus have two layers of hair: a woolly undercoat and longer shiny guard fur. These layers help to trap air next to the skin, which keeps the animal effectively dry, even when in the water. It is important that its fur coat remains completely clean and waterproof, in order for the animal to stay warm in the water.

"The fur of the platypus has amazing insulation properties. For them, it’s like wearing a really good quality wetsuit."
- Healesville Sanctuary Platypus Keeper

Cheek Pouches.
The only time that a Platypus feeds is when it is in the water. Whilst underwater, the Platypus temporarily stores small amounts of food in its cheek pouches. Then, when it emerges to the surface to breathe, the food is ground up between hard pads inside the bill.

Tail.
The tail of the platypus is broad, flat and paddle-like. It is used to store fat, which provides an energy reserve if food is scarce. Researchers apply a "squeeze test" to the tail in order to assess the amount of fat stored in there. From this they can rate the general physical condition of the platypus.

Spurs.
The spurs are located on the inner ankle of the hind foot of the Platypus. They show the sex and age of the Platypus. During mating season, the venom in males' spurs becomes much stronger.

Height and Weight.
An average male platypus weighs around 1,700 grams in a range from 1,00 to 2,400 g, whilst the average females are 900g in a range from 700 to 1,600 g. The total length on average of male platypus is 500mm in a range from 450 to 600mm, while females are 430 mm in a range from 390 to 550mm. Platypus do not keep a constant weight, their weight tends to fluctuate seasonally.

BODY TEMPERATURE
The usual body temperature for most mammals, including humans, is 37 - 38°C. However, the body temperature of a healthy platypus is normally around 32°C. This is believed to be an adaptation for saving energy, by reducing the rate at which body heat is lost in the water. Platypus tend to overheat rapidly if they are exposed to warm conditions out of the water, because of their thick fur coat.

BREEDING
As stated before, the platypus is a monotreme, a mammal with a single opening or vent for both reproduction and excretion. During breeding season, males can fight each other and the venom in their spurs becomes more poisonous. Platypus eggs have been recorded in nests from August to October. The female platypus lays from one to three round eggs, which have soft and leathery shells, in a nest consisting of wet leaves and grass. This is found in a nesting chamber which is dug into a creek bank. The incubation period lasts for 8 - 10 days, until the young platypus breaks out of the egg using its egg tooth. They receive nourishment by licking milk from the pores on the mother’s abdomen. For a duration of 4 - 5 months, the young stay in the burrow whilst the mother leaves and searches for food.

Monotremes The platypus is one of only three mammals to lay eggs. The other two are both echidnas - the Short-beaked echidna (which is found throughout Australia and also in New Guinea) and the larger long-beaked echidna which is native to New Guinea. The egg-laying mammals are collectively known as monotremes. The term monotreme means "one hole". This refer to the fast that these three species have only a single opening used both for excretion and reproduction (known as the cloaca).

The Enigmatic Platypus Despite the fact that the platypus is of major scientific interest and significance, much remains to be discovered about its basic biology and ecology. This largely reflects the fact that the platypus is extremely difficult to study because of its aquatic and mainly nocturnal lifestyle. The Australian Platypus Conservancy was established in 1994, specifically to undertake research on the platypus and identify the conditions necessary for its long-term survival.

Reporting Platypus Sightings A systematic program of trapping surveys is required to establish the distribution of platypus throughout Country Victoria. However, until such a program can be implemented, our knowledge of this remarkable species relies almost totally on reports of past and present sightings. A large number of people in rural areas are often in a good position to see platypus, especially anglers and farmers working near rivers. If you spot a platypus (or if you have seen platypus in the past) please report the details of date and time of sighting(s), how long you were able to observe the animal, details of the location (including a map reference, if possible) and any comments on the activities of the platypus concerned. Reports should be made to the Australian Platypus Conservancy PO Box 84 Whittlesea 3777 Tel: (03) 9716 1626 Fax: (03) 9716 1664

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