We’re going on a platypus hunt

By Peter Barrett
September 28, 2007

Your chances of seeing a platypus in the Yarra River in a place like this, Dights Falls in Abbotsford, are highest at this time of the year – but that still doesn’t make it an easy task. Peter Barrett joins the hunt for the most enigmatic and elusive of our native creatures.

Our eyes scan back and forth across the murky brown river, searching for ripples. It’s dusk and we’re perched with biologist Geoff Williams on the banks of the Yarra, 500 metres upstream from Dights Falls at Yarra Bend Park. We’re hunting platypus. It seems ludicrous to think something as exotic as this could be living within a stone’s throw of Victoria Park but apparently it’s true – there have been platypus sightings as far down the Yarra as Flinders Street Station (the last one was by Greens senator Bob Brown, in 1993). That said, platypuses generally don’t like the brackish water south of Dights Falls; there have been at least two credible sightings at the falls and plenty more further upstream in the past year.

The fact that a platypus would want to make its home in the lower reaches of the Yarra seems remarkable in itself. Although the river has slowly been recovering from industrial misuse over the past 40 years, pollutants such as heavy metals still enter the system when stormwater runs in. Yet the platypus is a reasonably hardy creature. All it needs is a steady food supply – preferably freshwater yabbies, bugs and worms – and a bank to burrow into, and it will move right in.

Williams, who has dedicated the past 13 years of his life to the study of platypuses, estimates there could be anywhere between 500 and 3000 living in the Yarra catchment area, but the number is probably at the lower end of this scale, taking into account the recent drought. Platypuses are solitary and males can be territorial. You’re unlikely to find more than eight platypuses in a one-kilometre stretch of river, which reduces our chances of spotting one today – particularly because the creature we are looking for is the same colour as the muddy water, sleeps up to 17 hours a day in an underground burrow and only comes out to forage for food, underwater, mainly at night. Still, that is our mission; and Williams says we have a tantalising, if slim, chance of spotting one.

Conditions, though, are excellent. It’s calm enough to see the tell-tale bow-wave ripple that platypuses make (distinct from a duck or a water rat) and, what’s more, we’re right in the middle of breeding season, the platypus’s most active period. The trick, Williams says, is to walk along the river bank for a while then stand dead still and spend five minutes scanning from bank to bank. We’ve already seen some black ducks (which are brown), coots, moorhens and even three European geese that have waddled across our path. But as yet, no platypuses. Then our chatter suddenly ceases as we both become aware of an interesting ripple emanating from the bank below us, about five metres away, just behind a half-submerged gumtree root. Platypuses will often stick close to the bank when they first emerge at dusk for a night’s foraging, especially when the water is quite deep (they are naturally buoyant and exert considerable energy when diving for food). Williams puts his binoculars to his eyes. It’s a false alarm, he declares: probably a water rat.

A 57-year-old father of three adult children, Williams has a trim salt-and-pepper beard, spectacles and the quiet yet determined demeanour of someone who spends hours in the wild trying to study the behaviour of one of the most frustrating and reclusive subjects available to science. After a stint as assistant director at Taronga Zoo in Sydney he became director of Healesville Sanctuary in 1988. He left Healesville in 1993 to study platypuses in the wild and promote their conservation. In 1994, he helped to set up the Australian Platypus Conservancy (APC), an independent, not-for-profit organisation dedicated to preserving the platypus in its natural habitat.

For weeks at a time, Williams, his three colleagues and a band of volunteers conduct surveys of platypus numbers around Victoria. The science is tough. Teams work through the night, laying nets in cold and sometimes remote river systems hoping to catch a platypus, which is then weighed and often fitted with a radio transmitter. “Everything about studying them is hard,” Williams grins wearily. “I never get over that. This is one of the world’s most unusual animals. They’ll always remain, to a certain extent, a mystery.”

Platypuses were predators towards the top of the food chain until Europeans, foxes and domestic dogs came along. The major threat to platypus populations today, though, is humans, largely through pollution that kills the insects, worms and crustaceans that platypuses eat.

In 1995, the APC and Melbourne Water got together to forestall the platypus’s slide towards the threatened species list and eventual extinction. They found platypuses to be useful indicators of water ecology; and so the Melbourne Urban Platypus Program was born. Live trapping surveys were conducted to map the distribution of platypuses around the city and monitor their reproductive success. An artificial rapid was built on the Yarra at Heidelberg in the mid-1990s by dumping 25 tonnes of rock into the water and, within a year, invertebrates returned to feed on algae that grew on the rocks in the now oxygen-rich water. Within two years, a platypus was spotted living there.

Until the late 1960s, Melbourne turned its back on the Yarra, which by then had become a stinking, sewage-polluted mess. Slowly Melburnians rallied behind our upside-down river and, with the culture shift, institutions changed too. In the 1970s, the Environment Protection Act stopped industry dumping waste directly into rivers and stormwater drains and long-term water monitoring began.

Melbourne Water formed in 1991 and started working with local councils to clean up stormwater pollution. Since then native revegetation programs and initiatives such as the fish ladder at Dights Falls – a series of pools that allow native fish to migrate up and down the river – have improved the ecology of the Yarra. Litter is now perhaps the most immediate threat to platypus health.

Healesville Sanctuary is a world leader when it comes to breeding the animal in captivity. Naturalist David Fleay was the first to have that rare success, with a birth in 1944. More recently, Healesville has recorded births in 1998 and 2000. Platypuses are monotremes, mammals that lay eggs (the only other egg-laying mammal is the echidna). Female platypuses dig nesting burrows and lay clutches of one to three eggs in late winter or spring. The 15- to 18?millimetre eggs take 10 to 11 days to hatch. The hairless platypus young lick milk that oozes through the skin of their mother (they have no nipples) and stay in the burrow for three to four months. Meanwhile, the female hunts every night, eating her own body weight in food. Ian Elton, Healesville’s head platypus keeper, is hoping that a recently revamped enclosure, with more natural features, will help get the animals in the mood for love. “It’s got big pool areas, waterfalls and rapids and there’s other animals mixed in as well – we’ve got water dragons and fish.
There’s a lot of activity going on all the time in the water and we’re hoping that will inspire them to breed.”

Healesville Sanctuary’s other role is to take in wounded animals – fish hooks, litter and fishing nets are the main culprits – and rehabilitate them. Four years ago, a severely malnourished young female platypus (pictured right) was caught in a drain that backed onto the Sanctuary’s platypussary. An elastic hair band had slipped over the animal’s bill and worked its way around her neck; the action of the band rubbing against her side caused severe cuts, exposing the collar bone, which had become infected. After months of intensive care at Healesville, the 400-gram animal (platypuses generally weigh between 700 grams and 2.4 kilograms), who was named Shelly, started putting on weight.

We meet Shelly at her new home, Melbourne Zoo, where it is time for a routine weigh-in. Zoo-keeper Ditar Uka, 50, has four buckets of food laid out on a stainless-steel table at the back of the zoo’s platypus enclosure: a squirming selection of live yabbies, mealworms, fly pupae and blood worms. The food is freighted in daily from Queensland. Uka, who has been handling platypuses for 20 years, disappears to the back of the room where the wooden nesting boxes are. A low growl is followed by the sound of some determined scuttling. “Listen to her, she’s furious. Sorry, Shelly, come on sweetheart,” coos Uka, grabbing her by her fat, fleshy tail. The platypus draws blood on Uka’s hands with her claws but soon she is in a calico bag and weighed. She’s down a little since last time but at 980 grams is still a very healthy weight for a female – certainly back to normal considering the state she was found in. With one last struggle in Uka’s arms, Shelly is returned to her nesting box and left alone.

Back in the wild, we finally give up our hunt on the Yarra at Kew and Williams suggests we might have more luck with an amateur spotter who has had considerable success near her home in Rosanna. Lyn Easton, 53, a bird watcher and mother of three adult children, started walking along the Yarra regularly for exercise after an operation on her back. Four years ago, she was out looking for a nesting pair of powerful owls but by chance she saw a platypus ducking and diving in the water. She became hooked and started keeping records of her encounters.

Members of the public provided nearly 100 reports of sightings in the summer of 1994-95 when The Age joined forces with the APC for the first major survey of platypuses in urban Melbourne. The exercise showed a concentration of numbers in the Yarra River upstream of Lower Templestowe and the Plenty River upstream of Greensborough. It also showed that the animal was not as numerous in some metropolitan areas as it should be; in others, it had disappeared altogether.

Aborigines called the platypus “boondaburra”, “mallingong” and “tambreet”. The first European description of a platypus dates to 1797, when Lieutenant-Colonel David Collins, judge advocate and secretary of the colony, saw a platypus in a lake near the Hawkesbury River in New South Wales. He described “an amphibious animal of the mole species … The most extraordinary circumstance observed in its structure was its having, instead of the mouth of an animal, the upper and lower mandibles of a duck.” In 1799, British naturalist George Shaw famously cut open a dried specimen sent to him to check that the strange animal was not some taxidermist’s Frankenstein hoax. He named it Platypus anatinus, Greek and Latin for “flat-footed” and “duck-like”. Unfortunately “platypus” had already been used to name a genus of beetles, so its scientific name was changed to Ornithorhynchus anatinus, referring to its “bird-like snout”.

While the platypus has a bill that looks like a duck’s, the bill is not hard but rubbery and flexible, dotted with hundreds of receptors that allow it to home in on the tiny electrical currents generated by the muscle contractions its prey make. It shuts its eyes underwater and moves its bill from side to side to navigate between rocks and submerged logs. It wasn’t until 1985 that the animal’s use of electro-reception was discovered.

Adult male platypuses have venomous spurs on both hind legs just that grow to around 15 millimetres long. It was only discovered recently that the venom contains enzymes similar to that of the Australian tiger snake, although it is unlikely to cause human death. The pain, however, is excruciating. People who have been spurred describe it as like having boiling water poured over the skin or someone grabbing your flesh with a pair of pliers. The venom can kill smaller animals. Dogs sent in to retrieve wounded platypuses (they were widely hunted for their pelts in the early 20th century) were routinely killed by spurring. In 1905, all hunting ceased when the platypus became a protected species.

The animal is now extinct in South Australia (except King Island, where a population was introduced) but remains reasonably common in other parts of its historical range from far north Queensland to Tasmania, though human encroachment on its territory has fragmented populations.

We arrange to meet Lyn Easton early in the morning in a car park in Banyule Reserve, just around the corner from the Rosanna Golf Club. She is carrying her binoculars and within 10 minutes she has already pointed out three pairs of tawny frogmouths, two cockatoos and a purple swamphen. The sun casts a golden glow and the Yarra gently flows between river gums and blackwood trees. Stopping at a break in the trees, we peer out over the water, looking for circular ripples. Platypuses dive for up to 40 seconds and resurface anywhere in a 25-metre radius. We look for the distinctive bow wave but the water is calm.
Taking to the path again, Easton stoops to pull up some nettles (she’s come equipped with gloves). Her passion for wildlife extends to weed eradication and during the course of the morning we stop several times to make a dent on the encroaching undesirables. Since becoming interested in platypuses she has also started to pay more attention to what she puts in her rubbish and recycling. Anything that could get wrapped around the neck of an animal if it ended up in the river – plastic milk-bottle tops, six-pack holders, plastic bags – she quickly cuts up with a pair of scissors.

At another favourite vantage point, I see something interesting in the water, but it turns out to be a stick. Easton regales me with tales of the other things she has seen on her walks. Some of the stories are macabre, such as the time she watched a tiger snake enter a kingfisher’s nesting burrow and heard the chirping chicks fall silent one by one.

Just as I am beginning to give up all hope, there one is. By a pipe leading down from the nearby golf club I clearly see a platypus, about eight metres away, nosing around some tree roots in the water. It is smaller than I imagined but the thrill of glimpsing one in the wild is no less exciting. Seconds later, it is gone. We try to follow the platypus (judging by its size, a female) in the direction it appeared to be swimming, but with no success.

Despite the brevity of the encounter, I can see how Easton became hooked. She’s had 280 sightings since her first on July 21, 2003.

“I’m always interested that people call it a shy animal. That isn’t my experience. Not that they’re friendly and come up to me or anything, but they’re there to be seen. They’re just not as hard to see as people might think. But so few people see them. That’s what fascinates me.” (m)

platy facts

1 A platypus would make a terrible pet. Besides being illegal (they are wild animals), it would be expensive: platypuses can eat up to their own body weight in live food (yabbies, meal worms and fly pupae, for example) every day.

2 Get spurred and you’ll end up in hospital. The venom in a set of adult male platypus spurs can kill a small dog and cause humans excruciating, incapacitating pain. An injury, should you be unlucky enough to receive one, should be treated in the same way as a snake bite: immobilise, keep calm and seek medical advice.

3 Platypuses are actually quite hardy. Their ability to live in low-oxygen environments might be the reason they have been able to survive polluted waters. By the 1980s it was thought they had disappeared altogether from Melbourne waterways but surveys undertaken in the 1990s showed they still inhabited some areas.

4 There may be hundreds of platypuses swimming in the Yarra. The Australian Platypus Conservancy estimates there are between 500 and 3000 platypuses in the Yarra catchment area, which includes all the Yarra’s tributaries.

How to spot a platypus

1 It’s best to start an hour before sunrise or sunset. Platypuses are most active at night when they feed but they can be seen during the day. They are brown and grow to 40 to 60 centimetres long.

2 Sit quietly by a stretch of water that is relatively calm. Find a spot that has good views up and down the river or lake. Don’t make sudden movements or noise and try and mask your silhouette behind a tree or shrub.

3 Look for the platypus’s distinctive ripple. When they are swimming in one direction, they create a recognisable long, narrow wake. They often dive and remain underwater for less than a minute, resurfacing within 25 metres to eat their food.

4 Water rats are easily mistaken for platypuses so it’s a good idea to have binoculars handy. Water rats can be identified by their distinctive white-tipped tail and the fact that they spend more time out of the water. Water rats leave a wide, trailing wake that’s quite different from the platypus’s.

5 Make notes. Write down the date and time, name of waterway and location (including map reference, if possible) and any comments about the behaviour of the animal. You can report sightings to the Australian Platypus Conservancy on 5157 5568 or see http://www.platypus.asn.au

Platypus sightings since 2003

1 Opposite Olympic Park, between the Swan Street and Morell bridges
2 Near Studley Park Boathouse in Kew
3 Near Fairfield Boathouse
4 Downstream from the mouth of Darebin Creek
5 Wilson Reserve, Ivanhoe
6 Banksia Street Bridge, Heidelberg
7 Near the mouth of the Plenty River
8 Finns Reserve, near the footbridge to Odyssey House
9 Westerfolds Park and Fitzsimmons Lane bridge, Templestowe
10 Near the mouth of Diamond Creek
11 Warrandyte Bridge area of Pound Bend
12 Bend of Isles

© Peter Barrett