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Platypus
 Habitat:
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- It is found in Australian fresh water lakes and streams.
- When out of the water the monotreme spends its time in
burrows just above the water level, in river or stream banks or under a
gathering of tree roots. Its burrow is distinguished by oval sections and it
may also have two ends of entry or exit. These burrows can be up to thirty
metres long, particularly when the female is nursing her young, an increase
in tunnel length is a protection from predators and flooding.
Diet:
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- The platypus eats fresh water insects and their larvae,
shrimps, yabbies, worms, tadpoles, small frogs and fish.
- Smaller prey is sifted from the bottom silt or gravel by
the bill which is pliable and very sensitive.
- When the platypus is under water, it closes its eyes, ears
and nostrils. Most information about its environment is obtained from
electroreceptors in the skin of the bill. The receptors enable it to
identify electrical fields created by the muscle movements of its prey.
- Juveniles have teeth, but lose them as they mature into
adults.
- The tail of the platypus stores fat for periods of low food
supply, or for when the female burrows to breed.
Social Behaviour:
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- Platypus’ are solitary animals, but do tend to share
small bodies of water.
- Males and females are differentiated by the males having a
sharp hollow spur on their hind legs which join to a gland in the groin
which produces a venom capable of causing great pain and incapacity in
humans and can be lethal to small mammals.
Viewing Opportunities:
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- They can be viewed early morning and late afternoon at the
Chambers Wildlife Rainforest Lodge platypus viewing area.
- They can be viewed up stream from the falls besides the
walking path at the Malanda Falls Environmental Park.
- Other viewing areas include the bridge over Maroobi Creek,
the Petersen Creek viewing area in Yungaburra and in front of the Atherton
pump station on crossing road.
Additional Information:
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- Another common name for the platypus is the Duckbill
Platypus.
- It is readily distinguished from the water rat or other
mammals that swim in Australian rivers and streams by its smooth swimming
action, low silhouette, absence of visible ears and its rolling dive. A
covering of long flattened guard hairs give it a sleek appearance.
- Found mainly in Australia’s freshwater lakes and streams,
the platypus is an egg-laying mammal (called a monotreme). There are only
two monotremes – the platypus and the echidna.
- When the dried skin of a platypus was sent to an English
naturalist in 1799, he thought it was a hoax created by a clever
taxidermist!
- It has features of both mammals and reptiles. Like mammals,
it is covered in fur, produces milk and has a four-chambered heart. Like
reptiles, it lays eggs, produces vitamin C in its liver (not kidneys) and
has similar kidney bones.
- The platypus is not endangered, but deteriorating water
quality in our waterways is adversely affecting its habitat. It is
classified as common but vulnerable.
- It is possible platypuses move out of freshwater
occasionally as they have been seen in brackish and salt water too.
- Platypuses once swam around with dinosaurs. In Argentina,
fossil remains prove that they existed at the time when the South American
and Australian land masses were joined in the super-continent Gondwana. A
fossil jaw 110 million years old of a platypus prototype was found in New
South Wales. However, this animal was almost twice as big and had teeth
unlike the modern version. This was possibly the largest mammal in the world
at that time.
- The platypus is smaller than most people think – the
average male is 50cm long and weighs 1.7kg, but females are smaller. The
platypuses found in the Wet Tropics (the northern limit of the platypus) are
noticeably smaller than those are elsewhere.
- It is distributed in eastern Australia from the high
altitudes of Tasmania and the Australian Alps to the tropical lowlands and
plateaus of northern Queensland. Evidence shows it once occurred in the
Murray River and its tributaries in South Australia, but it is now extinct
in this state except for an introduced population on Kangaroo Island.
- About half of the day is spent by the platypus feeding in
the water, but it is only able to spend up to about 10 minutes underwater at
a time. It generally comes up for a breath after about two minutes though.
The rest of the day is spent on land and in its burrow in a creek or
riverbank.
- Platypus blood is rich in oxygen-carrying haemoglobin and
red blood cells, so it is able to reduce its need for oxygen by reducing its
heart rate from more than 200 beats per minute to less than ten.
- The platypus constructs its burrow preferably in easily
worked loamy soils as opposed to rocky or sandy soils. Males and females
both build the living burrows, but only the female builds the nesting
burrow. This is generally longer than the living burrow (1-3m long) as it
may be up to 20m long. Entrances to burrows are a little above the water
level. If below, the water level changes and the platypus has to build an
alternative entrance.
- They are able to tunnel at the rate of one metre in two
hours. A single platypus may use a dozen living (also known as residential)
burrows.
- The platypus is a carnivore, feeding on aquatic
invertebrates such as insects and their larvae, worms, tadpoles, small
frogs, fish, freshwater shrimps, and crayfish. It usually feeds at night.
- When it dives, it swims to the bottom, rubbing its bill
through sand and mud to detect food which is stored in cheek pouches to
allow it to look for more. The food is then chewed and swallowed once the
platypus surfaces to breathe. It rests with its 4 legs extended on the
surface while it ingests the food. Young platypuses have proper teeth that
fall out soon after they first enter the burrow. Adult platypuses grind up
the food between hard pads inside the bill.
- The platypus needs to eat 15-30 percent of its body weight
per day.
- Its body temperature is normally around 32 degrees Celsius.
This can be compared to that of most mammals being 37-38 degrees. The
difference is possibly an energy saving adaptation allowing the platypus to
reduce the rate at which heat is lost in water. It can remain in
near-freezing water for 12 hours or more.
- The platypus has two layers of fur – a woolly undercoat
and a long shiny guard fur on top. These serve to trap air to keep the
animal dry and warm even when in the water for long periods.
- A very noticeable feature of the platypus is its bill. It
is soft and rubbery unlike the hard bill of a duck. When underwater, the
platypus relies on its sensitive bill to find food (as it closes its eyes,
ears and nostrils). Electrical currents can be detected by electro-receptors
in the bill, and they help to locate prey as it can detect the fields made
by the muscle movements of its fleeing prey. They also have pressure sensors
that may help it hunt and navigate beneath the water. On the surface of the
water, the platypus uses its acute hearing and sight to avoid potential
predators.
- It uses its back feet for treading water and helping its
tail in steering and its front feet for swimming by propelling it through
the water. The front feet are webbed with skin extending past the claws to
form large paddles for swimming. This extra webbing folds under the front
feet whilst on land so its sharp claws can be used for digging. The skin on
the back feet does not extend past the claws. The platypus is quite a good
climber too.
- Fat stored in the tail can be used when food is limited or
the animal does not feed (eg when the female retires to her burrow to breed.
The tail itself is used as a stabiliser when swimming, and being flat, it
enables the platypus to dive quickly. It is also used in burrowing.
- On hind ankles on males there are large, sharp spurs, 1.5cm
long in adults. These are mainly used during mating (as weapons between
competing males), but can also be used for defence and are connected to
poison glands by ducts. An injury from a spur can be very painful. The only
other mammal with a comparable spur is the echidna. Although the male
echidna has a similar spur on the ankle of its hind-leg, it lacks the
functional venom gland of the platypus.
- Recent research shows that the venom could actually be
useful as a new type of painkiller as it acts on pain receptor cells, which
is a property unique among venoms but shared with the active ingredient of
chillies.
- Breeding season varies depending on location. Mating takes
place (in the water) around August in Queensland, September in New South
Wales and Victoria, and October in Tasmania. After mating, the female
consumes large quantities of food and builds a nesting burrow. She retreats
into the burrow, blocking it for protection against both floodwaters and
predators. This also helps keep the nesting chamber (at the end of the
burrow) at a constant temperature and humidity for egg incubation.
- Two (or sometimes three) eggs are laid in a nest of leaves
and grasses. They are white, soft and leathery and, once laid, they are
covered in a sticky substance. When they are held against the mother’s
body, they are able to stick together.
- The female leaves the burrow for short periods about one
week after she has laid the eggs to swim and groom herself. About two weeks
after they are laid, she resumes feeding.
- Approximately 10 days after the egg laying, the young
hatch. They are fed on milk produced not from nipples, but from two patches
of skin (body pores) halfway along the mother’s belly. Until suckling is
completed, the platypus continues to feed on short expeditions, unblocking
and reblocking the burrow each time.
- The mother gradually spends more time away from the young.
When they are 3-4 months old (about three-quarter grown) they are ready to
venture out for their first swim. At about one year they are fully-grown.
- Living in captivity, individuals have been recorded to live
for up to 17 years, and in the wild, up to at least 13 years.
- An important element in its behaviour is the grooming of
its fur. Sometimes this occurs in the water, but more often it occurs on a
particular log or rock.
- The best times to see a platypus are at dawn and dusk. They
are shy and easily disturbed, so one must be quiet and patient.
- In certain places and at certain times of the year, the
platypus may be predominantly diurnal or nocturnal. Factors such as
locality, human activity, day-length, air and water temperatures, and
abundances of food influence their activity pattern.
- 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.
Additional Information: Platypus
of the Lamington National Park.
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