How scientists are rewriting the future of the tiny mountain possum

Imagine an animal that weighs about as much as a golf ball, sleeps for seven months at a time beneath a blanket of snow and has somehow survived ice ages, mass extinctions and continental drift. That’s the mountain pygmy possum, and right now, it is losing a battle that it never wanted to fight.There are thought to be fewer than 2,000 of these palm-sized marsupials left in the wild, in three isolated populations in the Australian Alps. They occur only in high-mountain sites, tucked into the cracks of rocks in places most people will never visit. As the planet warms, those mountain peaks are becoming less and less hospitable.It’s not just the temperature. Possums rely on snow for insulation for hibernation, and feral cats and foxes, kept at bay by deep snowpack for much of the year, now push further up the slopes as winters shorten. Their main food source, the Bogong moth, is also disappearing. It’s a perfect storm of threats that has brought the species to the brink.They were never really mountain animals to begin withIn a study published in Philosophical Transactions of the Royal Society B, the researchers argued, using fossil evidence dating back 25 million years, that the mountain pygmy possum’s ancestors never really belonged on a mountain at all; instead, they thrived in cool, temperate lowland rainforests, not alpine snowfields.These animals probably used rainforest vegetation to walk into the alpine zone during a warmer, wetter time in the Pleistocene epoch. As the climate changed again and the forests retreated, the possums were effectively stranded, barely able to survive by hibernating through the harshest months and avoiding the temperature extremes that characterise the alpine zone.In other words, the mountain was never their refuge. It was the last thing they could, and climate change now threatens to take even that away.A radical plan: Breed them somewhere warmerA team behind the abovementioned research came up with an unconventional solution. They established a breeding program at Secret Creek Sanctuary in Lithgow, New South Wales, to acclimatise the possums to lowland conditions where their ancestors thrived millions of years ago. The sanctuary is at about 1,000 metres. The aim is to gradually expose them to warmer temperatures, different food sources and changing seasonal rhythms, building adaptability in future generations before release back into the wild.The project received an unanticipated $190,000 boost from the Prague Zoo in the Czech Republic. That funding helped to build a dedicated breeding facility with purpose-built foraging areas, nesting spaces and closed-circuit monitoring. The colony has grown dramatically since the program began. What began with a handful of possums has ballooned to about 36, a sixfold increase that is a meaningful progress for a species so close to extinction.What captivity is teaching scientistsOne often overlooked benefit of the program is how much it reveals about a species that has proven almost impossible to study in the wild. Most of the year, mountain pygmy possums are hidden from sight, deep beneath snow and rock.A study in the journal Ecology in 2025 used detailed biophysical modelling to show that the possum’s hibernation window could shrink by as much as 43% even under a modest 2°C warming scenario, meaning the animals would have to burn far more energy just to survive the winter. Things get worse under a 4°C scenario. The study also found hibernation now cuts the possum’s yearly energy needs by 44-52%, meaning that any erosion of that window has outsized consequences for a species already operating on very thin margins.Secret Creek’s captive environment is helping to fill those gaps. Scientists have recorded previously undocumented mating behaviours, nesting habits and dietary preferences. The more we learn about how these animals actually live, the better conservationists are at protecting them, both in captivity and eventually in the wild.Why this matters beyond AustraliaTo an American audience, a golf-ball-sized Australian marsupial may seem a distant concern, but the mountain pygmy possum’s fate is really a preview of what climate change does to animals that can’t move fast enough. They get boxed in by rising temperatures above, habitat loss below and predators in the middle.What’s being trialled at Lithgow is more than a conservation project. It’s a new way of thinking about preventing extinction. If we can determine where a species was once comfortable from the fossil record and provide it with a physical path back there, that opens up a whole new toolkit for the climate era, when protecting the existing habitat is no longer always an option.The mountain pygmy possum has endured 25 million years of change on our planet. Whether it will survive this next chapter may depend on whether we are willing to meet it halfway.