Platypuses return to waterway for first time in 50 years

Platypuses have been reintroduced to one of Australia’s most renowned national parks more than 50 years after their last sighting.

Royal National Park, on the traditional Country of the Dharawal people, is home to a diverse range of flora, fauna and fungi, but has not had a confirmed sighting of a platypus for 50 years. That’s changed now, with the introduction of four female platypuses.

They will shortly be joined by four males and two other females as part of a repopulation initiative spearheaded by ecological scientists from UNSW, the Taronga Conservation Society and WWF-Australia.

These monotremes – egg-laying mammals – were collected with government approval from other parts of New South Wales, in the hope of providing a genetically diverse population to the region without upsetting other ecosystems in the process.

It’s hoped that the new population will flourish in safe waters along the nearby Hacking River, and act as bioindicators for the waterway’s health.

“For some reason, they’ve gone extinct, perhaps more than 50 years ago,” says Dr Gilad Bino, the UNSW ecologist who has led the reintroduction project.

“But conditions now seem to suggest that there can definitely be a viable population there, and so our efforts are, first of all, to restore platypus populations where we can, where conditions are favourable.

Ancient platypus cousin lived alongside dinosaurs

“Second …to really learn and improve our understanding in terms of the development of good conservation strategies to translocate, rescue and reintroduce platypuses to good habitat.”

To give the platypuses a fighting chance in their new habitat, Bino and his colleagues undertook rigorous assessments of the ecological conditions in Royal National Park. These include tests of water and soil quality, surveys of invertebrate food sources that comprise the platypus diet and depth studies of the Hacking and nearby Kangaroo Creek.

“All [of the tests] seem to suggest that conditions are quite favourable and can sustain platypuses,” Bino says. 

Invasive red foxes which are common threats to many native species within the park will be baited by parks staff to prevent predation of the new population.

The translocation and release of platypuses to the new environments was also done in collaboration with the La Perouse Local Aboriginal Land Council whose boundaries incorporate Sydney’s eastern beaches, Sutherland Shire and the Royal National Park.

“They’ve been very supportive of our initiatives, and definitely looking forward to having a thriving population,” Bino says.

Bino is hopeful the reintroduction project will provide a model for future initiatives around Australia.

Other such initiatives are being explored in Cardinia Creek east of Melbourne, where the species was wiped out by the 1983 Ash Wednesday fires, and the River Torrens/Karrawirra Parri, which runs through Adelaide.

“I really want Australians to appreciate freshwater environments and platypuses, and take responsibility over caring for our country. And there’s a lot to be done in terms of restoring waterways. That’s a critical aspect of protecting our environment, and our platypuses.”

Correction May 22, 2023: In our original report we incorrectly stated that Cardinia Creek was west of Melbourne.