Platypus reproduction Return to Platypus Page
The platypus is a warm-blooded mammal which lays and hatches eggs.
A female platypus produces a clutch of one to three eggs in late winter or spring.
The eggs are 15-18 millimetres long and have a thin, leathery shell, like those of snakes and lizards.
The mother is believed to incubate them between her lower belly and curled-up tail for a period of about 10 or 11 days as she rests in an underground nest made of leaves or other vegetation collected from the water.
A female platypus does not have nipples.
Instead, a rich milk is secreted from two round patches of skin midway along the mother's belly.
It is believed that a baby platypus feeds by slurping up milk with rhythmic sweeps of its stubby bill.
When the juveniles first enter the water at the age of about four months, they are nearly (80-90%) as long as an adult.
Male platypus do not help to raise the young.
Breeding season Return to Platypus Page
Platypus eggs have been recorded in nests from August to October, with some evidence that the animals breed a few weeks earlier in Queensland as compared to Victoria and Tasmania.
As platypus eggs are believed to develop for about a month inside the mother after being fertilised, platypus presumably breed as early as July in the warmer parts of their range.
Platypus Reproduction Table
Size Return to Platypus Page
Male and female platypus are both believed to be capable of first reproducing at the age of two years.
At maturity, male platypus measure on average 50 centimetres in total body length (bill tip to tail tip).
They typically weigh 1.2-2.6 kilograms, although the heaviest platypus yet recorded (captured in Tasmania) tipped the scales at 3 kilograms.
Adult females are smaller, measuring an average 43 centimetres in total body length and weighing 0.7-1.6 kilograms.
The platypuses found in the Wet Tropics (the northern limit of the platypus) are noticeably smaller than those are elsewhere.
Life span Return to Platypus Page
Platypus have been recorded to live to at least 16 years in the wild, though most individuals die at a much younger age.
The longest reliable age record for a platypus in captivity is 17 years.
More research is required to establish the animals' typical life span in the wild, although estimates of about 4-5 years for males and 6-8 years for females are not unreasonable.
Determining the exact age of a wild adult platypus is very difficult. In the case of younger animals, some information can be gained by examining the inner hind ankle.
From the time they first leave the nesting burrow, juvenile males are equipped with a conspicuous cone-shaped spur (initially about 1 centimetre long) on each hind leg.
At first the spurs are protected by a white chalky layer, which gradually chips away to reveal the slightly curved true spur by the age of about one year.
Juvenile females have tiny spurs, 1-2 millimetres long, which are shed by the age of about 10 months, leaving only a small pit to mark the spot.
Predators Return to Platypus Page
Reports by naturalists indicate that very large Murray cod and birds of prey (hawks, eagles and owls) occasionally capture platypus in the water, while carpet pythons, goannas and Australian water-rats may attack young platypus in the burrow.
It has also been suggested that predation by crocodiles may contribute to the lack of platypus on Cape York Peninsula in far north Queensland. Since European settlement, introduced species such as foxes, dogs and cats have also become predators on platypus.
Effect of floods Return to Platypus Page
Anecdotal evidence suggests that some platypus may die in severe floods.
However, flooding may also benefit platypus populations by temporarily expanding the size of the area available for foraging.
- Humans are a threat to the platypus, as well as its natural enemies like snakes, water rats, goannas, and introduced foxes.
- Platypuses were shot and trapped extensively in the early 1900s for their fur until legislation protected them.
- They are also threatened by pollution of waterways, erosion of stream banks, the building of dams, and stream improvement works.
- Natural vegetation along waterways should be maintained to protect the banks and provide platypus habitat.
Some unintentional problems humans cause towards platypuses:-
- drowning if entangled in fishing line, nets and litter
- becoming caught on fish hooks
- damaging their bills on glass, tin cans and other sharp objects
- losing the waterproof qualities of their fur due to oils and other chemicals
- getting pulled into pumps with intake pipes below water level
- having burrows destroyed from erosion, degradation of riverside vegetation and concrete channelisation
- losing food if insecticides or other chemicals kill their invertebrate prey
- getting attacked by cats and dogs.
Disease Return to Platypus Page
Few life-threatening illnesses have been reported in wild platypus, other than cases of bacterial pneumonia which probably developed after water was aspirated into an animal's lungs.
Platypus living in some parts of Tasmania are also known to suffer from a fungal disease, Mucor amphibiorum, which can cause serious skin abscesses and ulcers.
Fortunately, no cases of this disease have yet been found on the Australian mainland.