Some time ago, platypuses were common in Australia's urban scenes. Newspapers would often describe sightings of dozens at a time. But recently, most Australians have never even seen one of these incredible mammals.

Like many of Brisbane's waterways, it was once a beacon for platypuses where they can regularly be seen. However, recent studies show that these duck-billed mammals somehow disappeared from Kedron Brook and four other greater Brisbane waterways.

The last confirmed sightings at this spot of these egg-laying mammals were back in 2002.

Glum Future of Platypuses

A study published on January 7, 2021, in the journal Australian Mammalogy, is further evidence of the trouble the once widespread mammals in Australi face.

Tamielle Brunt, lead author and researcher at the University of Queensland says, "It's scary to think that we have already had these populations disappear under our noses." 

Brunt runs the Wildlife Preservation Society of Queensland's Platypus Watch Network.

In November, researchers from the University of New South Wales found that the endemic habitat for platypuses has shrunk by roughly a quarter in the past 30 years. Researchers alongside conservationists now nominate the platypus for threatened species status.

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Mysterious Vanishing of Australia's Platypus

Platypuses are elusive nocturnal creatures that tend not to make a splash which gives researchers a hard time seeing and monitoring. 

Brunt, together with colleagues, used a novel environmental DNA sampling technique to check over 28 rivers and creeks for platypuses. 21 waterways had recorded sightings of platypuses between 1990-2016.

By analyzing water samples for platypus DNA, researchers can tell if the animal was present in the waterways without having to see them.

Brunt explains, "because of how elusive they are, we could be losing them without knowing because we're just not regularly monitoring them."

A severe lack in long-term monitoring of platypuses means that land-clearing and regulations of rivers have altered their habitat and the decline may have gone unnoticed.

The coastal cities of Australia have recently rapidly grown suck as Brisbane, platypus habitats of waterways and creek banks are now surrounded by bustling suburbs.

Dr. Gilad Bino, a platypus researcher from the University of New South Wales that helped compile data for the research says that there are historic newspapers that report 'platypus migrations' with dozens seen at the same time.

Platypus is known to reside far north Queensland to Tasmania, roughly 2,900 kilometers in freshwater rivers with a wide range of habitats from tropics to semi-arid alpine areas.

Gilad explains that modern-day threats are compounding. Water extractions from creeks and rivers, dam and weirs building that create obstacles for the egg-laying mammals and riverbank erosions are only a few of the challenges platypus face today.

Although the platypuses' future may seem bleak and challenging, the mysterious decline of Australia's urban platypuses is far from extinction, says Gilad. On the other hand, as the climate crisis progresses and other threats persist, it does mean that the risk for local extinction is increasing. 

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