Also known as the duck billed platypus, these iconic Australian animals, along with Echidnas, are classified as Monotremes, and are the only mammals in the world to lay eggs.

The unusual characteristics don't stop there. Platypus find prey using electroreceptors in their bills to detect movement and males have venomous spurs in their hind feet to fend off predators.

From top to tail, a platypus can be 60cm long. Males can weigh 3kg and females 1.7kg. In colder climates they can grow slightly larger, but don’t come close to the size of prehistoric platypuses. Taxonomically, it’s the only surviving species in the family Ornithorhynchidae. Ancestors grew a metre long and had teeth to bite!¹

The name Platypus comes from the Greek word for ‘flat-footed’. They're awkward on land, walking on their knuckles to protect the webbing of their feet.

Expert swimmers, they use these webbed feet to propel themselves and use their tails to steer through the water.

Their dense, silky brown fur is both waterproof and insulating – along with the fat reserves in their tails, their fur allows them to stay warm underwater.

Their ‘duck bill’ is flexible, rubbery and feels like suede. It’s used to dig up food from the riverbed. A Platypus bill is also highly sensitive. They use electroreceptors on their bills to detect electrical signals given off by moving prey.

With their eyes, ears and nostrils closed, Platypus use electroreception to detect movement underwater.

This explains their characteristic side-to-side head movement while hunting. In this way they hunt for prey underwater for 30 to 140 seconds at a time.

The Platypus is one of very few venomous mammals in the world. A spur on the male’s hind foot is connected to a venom-secreting gland, so they can deliver a toxic blow when fending off predators or in aggressive encounters between rival males. For humans, the venom is non-fatal, but it can cause swelling, loss of muscle control and severe pain.

It’s little wonder that 19th Century European scientists found it difficult to believe the Platypus was real, and thought this half-beaver, half-bird to be an elaborate hoax.

Today the Platypus is celebrated as one of Australia’s most unusual and unique animals – it’s the state animal of NSW and proudly represented Australia in the 2000 Olympics as a mascot!

The Murrumbidgee, a wide river, runs through forested hills at Scottsdale Reserve.

Murrumbidgee River at Scottsdale Reserve. Photo by Wybe Reyenga.

Where do Platypus live?

Platypuses are only found in east and south-eastern Australia. They’re found in freshwater creeks and rivers of Queensland, New South Wales, Victoria and Tasmania. They can live in many habitats, from tropical rainforest creeks to streams in alpine areas.

Platypuses are listed as Vulnerable in Victoria and endangered in South Australia¹, where it's only found on Kangaroo Island off the coast. The International Union for Conservation of Nature has upgraded their status to ‘Near Threatened’. Elusive by nature, there’s a lack of reliable data about where and in what numbers they occur. They’re protected by legislation in all of Australia’s eastern states.

How do Platypus behave?

Platypuses are mostly nocturnal. During the day they sleep in the chambers at the end of riverbank burrows. At dusk they emerge to search the river bottom for food, sometimes hunting for 10 to 12 hours a night.

They’re completely carnivorous (meat-eating) and mostly eat invertebrates: swimming beetles and waterbugs, insect larvae, tadpoles, worms, snails and shrimp.

Bottom feeders, they forage along the bottom of rivers and creek beds, often scooping up gravel and dirt along with their prey. They can store this in their cheek-pouches, and bring it all to the surface to eat.

Like echidnas, today's platypus doesn't have teeth. Instead, it uses a grinding plate to mash the gravel, soil and food slurry, scooped from the riverbed. It can eat an impressive amount of food in a night – up to 20% of its own body weight!

Females breed at 4 years. After burrowing deep into the riverbank, pregnant females lay one or two eggs. Here, curled up in protective chambers, they incubate their eggs between their tail and rump.

Bean-sized babies emerge from the egg after 10 days and are fed milk for about four months.

Platypuses don’t have nipples; instead milk is secreted through pores and licked off the mother’s skin or fur.

By the time the young are weaned off milk they can swim independently. While largely solitary, Platypuses don’t mind sharing their waterbody with other individuals.

They can live to 12 years old in the wild.

Threats to Platypus

Given their dependence on freshwater systems, habitat destruction and waterway pollution threaten this species.

Water extraction, dams and diversions to water flow have a big impact. Water quality and in-stream habitat (such as submerged logs) are critical so degradation of these elements is a threat.

Run-off from pasture (sediments and nutrient load) can degrade Platypus habitat, as can sediment run off following major fires and drought.

Platypuses are eaten by snakes, water rats, birds of prey and occasionally crocodiles. It’s likely that foxes, dingoes and wild dogs kill Platypuses that venture on land. They were once hunted for their fur – pelts are both warm and waterproof.

A juvenile Platypus in the hands of a volunteer who rescued it.

Lucky the platypus. Photo Richard Swain.

What Bush Heritage is doing

Sit quietly by the water at our Liffey Valley, ‘Nameless’ Sylvan or Scottsdale reserves and you might spot this shy species. We look after their habitat by maintaining riparian vegetation (which filters run-off into waterways) and in-stream habitat (e.g. fallen logs, deep pools) and by managing stream-bank erosion.

The juvenile pictured above was rescued from a sinkhole at Black Rock Gorge, which is a little travelled and pristine section of the upper Murrumbidgee River … part of which forms the Scottsdale Reserve boundary. Unable to climb out, it was swimming ‘round and round’ and by the bedraggled looks of it, might have been there for a while!

On being hauled up, the little platy rested, exhausted in the rescuer’s hands, but to our delight after about 5 minutes started to preen itself. Twenty minutes later, its fur fluffed up like a mink coat on parade, it was larking about amongst the rocks!

Bush Heritage at Scottsdale is a key partner of the Upper Murrumbidgee Demonstration Reach (UMDR).