They are stealthy, shy and tricky to spot — but volunteers are being asked to look a little closer at their local waterways to help track the elusive and near-threatened platypus.
Late winter is when the animals are most active, meaning volunteer groups across southern New South Wales and the ACT are braving the chill to compile a platypus census.
Antia Brademann is the Cooma region Waterwatch coordinator and said it was the fourth year they had surveyed the animals in the same stretch of the Upper Murrumbidgee River, around 5 kilometres from the town centre.
"The platypus is a very shy and cryptic creature," she said.
"One of the challenges of the survey is that you are on a big river and you are looking for some small activity."
On the Upper Murrumbidgee river passionate conservationists are joined by first-timers, keen to see a platypus in its natural habitat.
Young couple Mike Frier and Rebecca Canham travelled all the way from Bondi in the early hours of the morning to tick off something on Mr Frier's pre-30th birthday bucket list.
"It was amazing, it was really fun," Mr Frier, who was born in England, said.
"They are really unusual, abnormal animals so I have always wanted to see one."
Unfortunately, on this occasion no platypus were sighted by the volunteers, but a native water rat was spotted, which is also a species considered to be in decline nationally.
The absence of observed platypus may indicate that more human help is needed in the future, but for now it is a watching brief.
"This group survey is really important for us," Ms Brademann said.
"It is the only formal platypus monitoring that's occurring in the Upper Murrumbidgee."
How citizen science is helping save the platypus
For biologists, this citizen science has huge potential to gather valuable baseline data on the near-threatened species.
Platypus numbers have been in decline across eastern Australia and Tasmania since European settlement, due to habitat change, reduced river flows, exotic fish like carp and discarded waste including fishing line, nets and illegal yabby traps.
"It's hard to save a threatened species when it is on its last legs," Ms Brademann said.
"To assist our ecosystems to be productive and our species to survive it's much better to look after things to allow them to breed … before it becomes a threatened species and that's why this information is so important."
Waterwatch says their four years of surveys on the Upper Murrumbidgee River suggests platypus numbers are stable at that site.
And you don't have to take part in organised surveys to help out.
"We are also encouraging people to tell us their platypus sightings at any time of the year," Ms Brademann said.
So, how do you spot a platypus?
Local conservationist and retired nurse Melinda Kent said you start by selecting a section of the river, and just keep watching.
"It's so exciting to actually see a platypus in the wild," she said.
"Scanning the area consistently for any sign of ripples or a bubble, we are just scanning because they are very silent."
Ms Brademann's top tips are to brave the chill during August and September and head out in the early morning or late evening.
And be on the lookout for three distinct shapes sitting on top of the water.
"It will duck dive down, you will see a very rounded back and you will see the classic bullseye rings on the surface of the water with the bubbles in the middle," Ms Brademann said.
"When you see a water rat and a platypus it is something you remember."
"We find these surveys are a wonderful way of getting people engaged and appreciating the river."
More information on the platypus survey can be found on the Waterwatch website.