What scientists have learned from the oldest wild platypus ever found

The platypus, a unique egg-laying mammal native to Australia, faces many threats in the wild: climate change, predators, pollution, flooding and shrinking freshwater habitats. For males, mating is a dangerous affair, injuring each other with their sharp, poisonous spurs.

But scientists recently identified a male platypus that was just under 24 years old, the oldest recorded age for a platypus living in the wild, in an area that had experienced nearly seven years of drought during its lifetime. The discovery offers rare insight into one of the world's most mysterious creatures and tips on how to help them live longer.

“We're now getting a better idea of ​​how they can live to a reasonable age when conditions are right,” said Geoff Williams, a biologist with the Australian Platypus Conservancy who helped study the platypus before bringing it home.

The platypus is fast, slippery and declining in numbers and difficult to study. About 300,000 of these animals still live in eastern Australia and Tasmania. Special equipment is needed to analyze and catalog them. The males' venom can cause people months of pain.

The age of an adult platypus is difficult to say. When platypuses are young, changes to their bodies are more noticeable, allowing scientists to estimate what stage of development they are in. Once they reach adulthood, they hardly change at all.

Scientists knew the age of the platypus they found in a small creek near Melbourne in September because they had already tagged it in November 2000, when they determined it was about 12 and a half months old, according to a published paper. in this week Australian Mammalogy.

Platypuses have lived longer in captivity. The oldest known platypus recently turned 30 at a zoo in rural Victoria. But in old age it developed arthritis in one wrist, cataracts in both eyes and deafness — signs of aging that “might have precluded her survival had she lived in the wild,” the study authors wrote.

Scientists say the discovery of the oldest known wild platypus, which broke a record previously held by a female last seen in New South Wales at the age of 21, could help preserve the species. In particular, studying its habitat, Monbulk Creek, provided some clues for conservationists.

One of the keys to the platypus's long-term survival was a pool of water that persisted throughout the seven-year drought, Williams said in an interview. The platypus lived near an artificial reservoir that had supplied water to a local community in Melbourne's south-eastern suburbs about a hundred years ago, providing a refuge during long dry spells.

Conservation groups could help other members of the species by identifying and strengthening populations near similar pools that are deep and large enough to hold water during droughts, he added.

“It's important to make sure the population is still alive,” says Gemma Snowball, a zoologist at Ecology Australia, an ecological consultancy that helped identify the platypus, “so that everyone can see them and see that the iconic Australian species is still alive. in the wild.”

Scientists also said the area's low population density could have helped the platypus survive. A higher density could have led to more breeding and foraging activity, causing the animal to leave the water more often and risk predation, Ms Snowball said. The male could also have taken more risks by fighting over or defending a female.

In addition to its habitat, the animal itself also provided exciting new information for scientists about the landmark species.

Over its lifetime, the platypus' spurs had worn down to half its length, from 19 to 9.5 millimeters, Williams said. The observation opened the possibility that scientists could use that feature to measure the age of adult platypuses in the future.

“That's something we haven't been able to confirm for a long period of time,” he said, adding: “If we could get a few more shots like this, we could start to estimate what kind of decline is happening.” takes place over time. .”

For Mr Williams, the discovery was also a sign that the endangered species could be more resilient than scientists had feared. In Monbulk Creek, “platypuses are highly endangered,” he said. “They could become extinct at any moment.” Yet an animal survived there for a long time and remained sexually competitive.

“It gives us much more hope,” he said, “that even if climate change predictions are correct, if Australia becomes a lot drier in some places and platypus populations face the prospect of living in isolated areas for much longer. areas they can survive for quite long periods of time when they are under pressure.”