Of Moths and Marsupials

The ancient relationship between the mountain pygmy possum and the bogong moth reveals the complexity of global climate change—and the lengths people may have to go to save some species from extinction.

Linda Broome pulls herself up a near-vertical slab of granite, leaps nimbly over a snow-lined fissure, and dives head-first into a crack in the rocks. At 67, she knows Mount Blue Cow like the back of her gloved hands. Every November for the past three decades, she has lead volunteers up this 2,000-meter (6,500-foot) peak, and a handful of other high-altitude boulder fields in Australia’s Snowy Mountains, where the states of New South Wales and Victoria meet. The team visits to monitor the population of critically-endangered Burramys parvus—better known as mountain pygmy possums.

November is springtime in the high country. Drifts left by a late snowstorm are melting, and frogs croak enthusiastically in the fens. Anemone buttercups—rescued from extinction 65 years ago when the government banned cattle grazing here in Kosciuszko National Park—wave white-and-yellow among snowgrass and snowgums and fragrant alpine mint, while little ravens caw from the windswept sky.

The nocturnal possums have hibernated under the snow all winter, dropping their body temperature to just above freezing for up to seven months. Then, one night a few weeks ago, they woke up. Broome, a threatened-species officer at the New South Wales state environment department, retrieves a rectangular aluminum trap from the crack and backs out. She carefully reaches inside, past a lining of cushion-stuffing, and retrieves a whiskery, mouse-like creature with black eyes and brown-and-gold fur.

She holds it by the base of its long, scaly tail, which curls around her finger. “It’s alright, darling,” she coos. “You’re so sweet.” Broome and volunteer Carlie Armstrong work together to insert a minuscule microchip into the folds of skin at the possum’s neck, clip a snowflake-sized disc of skin from its ear for genetic analysis, and check for parasites.

They place the creature in a cloth bag and weigh it: 34 grams (1.2 ounces). This one is female, with a handful of jellybean-like joeys in her pouch, and seems unconcerned as she perches on Broome’s finger and sips water from a bottle lid. While Armstrong uses the metal trap pin to nudge the possum’s droppings into a vial, Broome releases the animal. She scurries over the neon lichen and disappears into a crevice.

The little marsupial’s dual mission for the coming summer is to raise her young while doubling her body weight, so she’s fat enough to hibernate again. Fortunately, just as she and the other possums were stirring beneath the boulders, breakfast arrived on their doorstep.

Every spring, vast numbers of bogong moths (Agrotis infusa) migrate as much as 1,000 kilometers (600 miles) from the western plains of New South Wales and Queensland to the high country, crawling into caves and among the rocks to avoid the heat—a summertime form of hibernation called aestivation. The alpine possums eat other invertebrates, as well as fruits, seeds, and nectar, but the fatty bogong moths are their favorite food; at the highest elevations, the migrating moths make up as much as 50 percent of their diet. “It’s a massive movement of protein into the mountains,” says Broome—one that feeds not just possums, but ravens, lizards, and other small mammals. 

In the past few years, though, New South Wales and the rest of southeastern Australia have ricocheted from drought, to fire, to flood, threatening to unravel the ancient, intertwined relationship between the moths and all the animals that depend on them—including the few thousand mountain pygmy possums known to exist.

From 2017 to 2020, prolonged droughts in Queensland and western New South Wales caused moth numbers to drop from more than 4 billion to perhaps 20 million. As a result, baby possums starved in their mothers’ pouches. Meanwhile, bushfires ravage other mountain food sources, and Australia’s snow is itself endangered.

The dance between moth and possum demonstrates the complexity of global climate change, and how extreme weather in one place can alter environments thousands of miles away. Together, these creatures have become symbols of what Australia stands to lose in this warming century: unique species, ecological relationships, and even entire ecosystems, alongside human homes, livelihoods, and lives.

But despite their small size, low numbers, and harsh habitat, these possums are surprisingly resilient. The fossil record suggests that the tiny marsupials have adapted to dramatically altered climates in the past, and they may do so again—provided they have some help.

Until the 1960s, scientists considered the mountain pygmy possum nothing more than an interesting fossil. In 1894, Scottish doctor and paleontologist Robert Broom had found minute Pleistocene-age teeth and jawbones in a limestone deposit near the Wombeyan Caves, between Canberra and Sydney.

The jaw featured a most unusual tooth, “unlike that of any known marsupial,” Broom wrote—a large premolar with six deep grooves that gave it a serrated edge. Speculating that it belonged to a missing link between kangaroos and tree possums, he gave the presumably extinct creature its scientific name, borrowing Burra from a local Aboriginal word for the rocky caves, mys from the Greek for mouse, and parvus from Latin, meaning little. “So it was a small rock mouse, which was very prophetic,” says Linda Broome (no relation to Broom, but she appreciates the resonance: “it’s destiny that I studied this thing.”)

A few more fossil remains turned up over the following half-century, and in the 1950s, David Ride, director of the Western Australian Museum, used vinegar to dissolve the rock encasing the fragile Burramys bones. With this clearer view, he decided they were more closely related to Australasian possums—Phalangeriformes—than to kangaroos, and that the Burramys puzzle had been solved. (American opossums are also marsupials, but are more distantly related.)

Then, in August 1966, people staying at a Mount Hotham ski lodge in Victoria noticed some strange furry creatures stealing bacon from the stove. Australian naturalist Norman Wakefield took a look at a captured one and recognized its distinctive ridged tooth immediately. “Burramys had come to life,” Ride wrote of the event. “The dream dreamed by every paleontologist had come true. The dry bones of the fossil had come together and were covered with sinews, flesh and skin.”

Because other species of pygmy possum live in trees, ecologists initially assumed that the possums had hitchhiked to the lodge in a load of firewood. But by the early 1970s, they had been captured in the wild at various alpine locations in Victoria and New South Wales—even, in 1972, among the boulders near the treeless summit of 2,228-meter (7,310-foot) Mount Kosciuszko, Australia’s highest peak. A small rock mouse, indeed.

In the early ’80s, as developers were building a new ski resort at Mount Blue Cow, a national parks contractor discovered a population of pygmy possums precisely where the runs were being laid out. The state government set out to find someone to assess the resort’s impact on the animals.

At the time, Linda Broome was living in Logan, Utah, completing her doctorate at Utah State University. Having just spent four years tracking deer mice across the rolling sagebrush country of Wyoming, she was probably the only person from Australia—that mostly sunburnt country—who had worked with small mammals in the snow. She got the job, and came home. When she first arrived at the foot of Blue Cow in 1986, she looked up at its steep, rocky profile and thought, “Hell’s teeth! What have I done now?”

For the next few years, she trapped the possums and fitted them with wedding-ring sized radio transmitter collars she had soldered together out of cable ties, dental acrylic, and hearing-aid batteries. She tracked their habits and movements, mostly at night. Once, she dodged a dynamite blast while setting possum traps in a boulder field that workers were clearing for a ski run.

And as winter blizzards raged, she clambered over the mountain in snowshoes with her radio receiver, finding the possums unexpectedly still. That was how she discovered that they hibernate—a rare behavior for Australian mammals.

Over the decades, she and other researchers identified three genetically-distinct populations: the one here in Kosciuszko National Park, another at Victoria’s Mount Hotham and the Bogong High Plains, and another at Mount Buller, also in Victoria. They have watched the possums weather fire and ice, dry years and wet ones. The animals’ total numbers fluctuated between around 2,000 and 3,000 adults, depending on climate, food availability, and predators—and on the mysterious peregrinations of the bogong moths.

In September 2000, a strange cloud appeared on satellite maps, approaching Sydney. Weather forecasters worried that rain would disrupt the Olympic Games Closing Ceremony. But the “cloud” turned out to be a huge swarm of bogong moths. Attracted by the stadium lights, they tumbled dizzily above the spectators, and threw themselves against the soloist as she sang the Olympic hymn.

It was not the first time that bogong moths had been part of human celebrations. For the Aboriginal peoples of the high country, bogongs have been an important seasonal marker for thousands of years, says Jakelin Troy, a linguist and the Director of Aboriginal and Torres Strait Islander Research at the University of Sydney. Troy’s people are the Ngarigu, and the Snowy Mountains are her Country. That word, Country, means more than just land. It encapsulates Aboriginal peoples’ embodied experiences of being immersed in the environment of their homelands—and their duty to protect them.

“Bogongs are just such a core part of our story,” Troy says. “They blend in so beautifully with Country. They look like the granite, they look like fallen timber—and they have been this important source of food for my people.” They’re also delicious, she says. “Get all the mothy stuff off and they’re like peanut butter.”

The moths feature in stories and songs across southeastern Australia. At Uriarra Station, a ranch half an hour’s drive from Australia’s capital, Canberra, Paul Girrawah House of the Ngambri people introduces me to a sacred site. The Uriarra Moth Stone is a flat expanse of granite the size of a basketball court, overlooking undulating fields where sheep graze beneath forested hills. “Uriarra means ‘running to the feast,’” House explains. “As soon as the bogong arrived, it was the sign. The message went out, and people came.”

His ancestors collected the moths from nearby mountaintop caves and carried them here in dillybags woven from stringybark and reeds, to feed guests. The rock, House says, “is a feasting table,” and everyone, friend or enemy, was invited. Here and in the Snowy Mountains, bogong moths brought people together, fueling summer festivals where marriages were arranged, ceremonies performed, trade conducted, and disputes resolved.

“Bogongs are just such a core part of our story,”

— Jakelin Troy, University of Sydney

Settler Eliza McDonald, who lived at Uriarra Station in the mid-to-late-1800s, recalled watching local Aboriginal women set fires on the stone to heat it and cook the moths. Some years were so rich that it took the people who had gathered weeks to devour all of the insects. It was “something so far better than [lowland] possum and yams,” McDonald remembered, “that the ebony skins of the eaters literally shone, and their bodies showed a plumpness quite in contrast with the leanness of normal times.”

By the mid-20th century, colonization and land dispossession had largely ended these traditions. But the moths remain enormously significant, House says. Today, he has brought his son, Reuben, to see the stone for the first time, and to sing some of the old songs.

“To come back here, there’s a feeling of empowerment,” Reuben tells me. The 26-year-old has the image of his Ngambri great-great-great grandfather, Henry “Black Harry” Williams, tattooed on his shin. The design is based on a 1901 photograph taken right here on Uriarra Station, where Williams worked as a stockman and laborer. Above Reuben’s knee, there’s another tattoo: a bogong moth, flapping across his thigh. It’s a symbol of his heritage, and of resilience, he says. Persistence in the face of change. The bogong moth “makes me feel strong,” he says, “and more proud to identify as a Ngambri man, from here.”

The bogong moth’s annual migration is one of the world’s natural wonders. Only the epic journey of the monarch butterfly across North America compares, says entomologist Eric Warrant, an Australian based at Lund University in Sweden.

While the monarch takes four generations to complete its migration, the bogong moth does it in one, starting at various sites on the western plains of New South Wales and Queensland, and returning home after their summer mountain sojourns. “They’ve never made this journey before, and they have never had anybody to tell them how to get there, and their parents have been dead for three months. This is a terribly difficult thing to do,” says Warrant.

In 2012, Warrant and his students began a series of experiments to investigate how the moths knew where to go, and how far to fly, and when to stop. Being nocturnal, they couldn’t use the sun, and the moon’s phases made lunar navigation unreliable. The tests showed the moths relied in part on their magnetic sense for navigation, but—like hikers training a compass needle onto a distant tree—they also appeared to use visual cues.

The question was: which cues? It occurred to Warrant that “the Milky Way is an enormously strong visual stimulus.” To a moth, it probably looks like “a lovely stripe of light,” brightest in the south, and fading in intensity as it arcs into the north.

At his holiday home near Adaminaby, near the northern end of the Snowy Mountains, Warrant put the idea to the test. He built a new lab from scratch in 2017. No magnetic materials were allowed; the roof was made of corrugated aluminum instead of steel, which contains iron.  Inside was an arena where the moths could fly in a kind of magnetic vacuum, so the scientists could study the insects’ visual sense in isolation.

Using a computer program devised for planetariums, Warrant’s team projected the seasonally-and-geographically correct night sky above bogong moths they’d captured outside during their autumn migration away from the mountains. Inside the arena, with only the projected sky for guidance, the moths knew exactly where to go.

When the researchers rotated the sky image by 180 degrees, the whole population of bogongs turned and flew in the wrong direction. And when they randomized the stars’ positions, the moths were completely disoriented.

“It is totally mind blowing,” says Warrant. The moths have somehow inherited these star-maps and magnetic signposts from their parents, so they’re born not only knowing which way to fly, but they can also correct their course on the wing.

And yet, these extraordinary creatures are suffering. Their numbers decreased after European settlement in the 1800s, then remained stable before declining gradually from about 1980. Researchers aren’t sure why, but speculate about changes in climate, as well as land use in the moths’ breeding grounds, such as clearing, increased grazing pressure, or pesticide use.

Until recently, however, they still numbered in the billions. In a typical year, the caves at the moths’ first stopping-point—Mount Gingera, a 1,857-meter (6,093-foot) peak in the Australian Capital Territory’s Brindabella ranges—are “completely carpeted in moths,” says Warrant. Each individual overlaps its wings with those of the moth next to it, a behavior known as tiling. “They look like scales of a fish. There are 17,000 moths on every square meter of cave wall—it’s an amazing sight.”

But in 2017, the rain stopped falling. In the moths’ winter breeding grounds on the plains, few plants grew, starving kangaroos and moth caterpillars alike. The following summer sweltered, and when Warrant went up to the caves on Mount Gingera, he found them bare. “From millions upon millions of moths, to nothing! That for me was shocking in the extreme.”

Large populations can weather one severe year. But for the next three years, rainfall in the state was the lowest on record. Meteorologists estimated that temperatures on the plains were higher than at any point in the previous 2 million years. By the time the drought broke in 2020, Warrant and other bogong moth researchers calculated that the population had plummeted by 99.5 percent. In 2021, the bogong moths joined the mountain pygmy possums on the International Union for Conservation of Nature’s Red List of Threatened Species. That summer, despite two years of good rainfall, surveys of known aestivation sites in Australia’s northern Alps, including Mount Gingera, the Main Range, and Mount Blue Cow, found few to no moths.

There was a time when Warrant would have laughed at anyone predicting the bogong moth’s extinction. Like 19th century Americans marveling at the super-abundant passenger pigeon, he had thought the moths were invincible. Now, he says, it’s clear that “this apparently incredibly resilient insect is very vulnerable to bad conditions.”


Decrease in bogong moth population after three-year drought

It’s 6:30 am, and Linda Broome is checking her moth traps at Charlotte Pass, a few miles southwest of Mount Blue Cow. A bowl-like valley cups a clutch of ski lodges, its steep sides lined with gnarled snowgums and striped with chairlifts and pomas. Every year, Broome monitors the population of pygmy possums that lives among the boulder fields beside the road, and she has long kept an eye on their primary food source.

She lifts a funnel from the mouth of a white bucket perched on top of a rock, and removes torn pieces of newspaper. The moths—attracted by a light placed atop the bucket overnight—whirl manically underneath, the scales rising from their wings like dust motes in the light. “We’ve only got a few hundred here,” Broome says. It’s a partial recovery from the last few dire years, but nothing like the thousands she typically captured before the drought.

Hungry ravens edge closer. Volunteer Zoe Barber reckons they have “teenage boy energy,” and it’s true—they strut about in delinquent gangs of five or six, looking for mischief. Torn-off moth wings litter the lichen, evidence of the conspiracy’s last feast. Broome tips out the bucket and the moths scurry for the nearest crack. She shoos them deeper, out of the ravens’ reach.

Ecosystems are complicated, and it can be hard to untangle cause and effect. But consecutive years of low moth numbers do harm possums—especially those at the highest elevations, where there’s little alternative food. In Victoria, when bogong moth populations plummeted in the summer of 2017-2018, researchers found possum after possum with their pouches full of dead babies. In one area, 95 percent of litters died.

“There were no signs of injury, no bacteria, no illness, no viruses,” says Marissa Parrott, a reproductive biologist from Zoos Victoria. “They simply starved to death.” The government team managing pygmy-possum recovery, including Broome, Parrott, and others, concluded this was a conservation emergency that required direct intervention. Zoos Victoria got to work on a long-term, possum-specific supplementary food program and came up with a recipe that mimicked the nutritional qualities of bogong moths, plus the other elements of the animals’ natural diet. It included macadamia nuts, coconut oil, mealworms, egg white, and vitamins. A commercial company made the gourmet mixture up as a dry powder, and then the researchers baked it into bogong “bikkies”—Australian slang for cookies.

The team aimed to create something the possums would like, but not love—more gym protein bar than sweet treat, Parrott says. Trials with captive possums confirmed that the animals would eat the bikkies only if they couldn’t get their bogong moths or other natural foods.

In November 2019, Parrott’s team successfully tested their concoction in the wild among the struggling possums in the Victorian boulder fields, using a variety of different home-made feeders. But it wasn’t until January 2020 that the bikkies really proved their worth. That month, Parrott got a call she would never forget. It was Linda Broome, and she didn’t even say hello. “It’s gone,” Broome said. “There’s nothing left.” Bushfires sweeping across vast areas of Australia’s southeast had hit northern Koscuisko National Park, near Cabramurra. The area’s tinder-dry boulder fields were home to a thriving population of mountain pygmy possums that Broome and her team, including PhD students Hayley Bates and Haijing Shi, had discovered in 2010.

Broome knew the possums had likely survived, deep in the damp crevices. But when she visited days after the conflagration, she found the still-smoking hillsides devoid of vegetation and insects for the animals to eat, and no water for them to drink. “Please tell me your food and your feeder worked?” Broome asked Parrott. It was one of the proudest moments of Parrott’s life that she could say yes—that the prototypes had been successful, and that they were ready to deploy.

The Zoos Victoria team sent bags of bogong bikkie mix and prototypes of the feeders to Broome, and the volunteers got making and baking. Every week for the next two summers, the National Parks and Wildlife Service Discovery Rangers, aided with baking by local school children, delivered fresh bikkies to 60 feeders stationed across the burned boulder fields.

By the end of 2022, the animals were thriving without support. “On one of the sites, almost every trap had possums,” says Bates, now an ecologist at the University of New South Wales. Vegetation was returning only slowly, but other prey like bugs and beetles were already crawling around the boulders. The expensive, labor-intensive experiment had worked—proving that in extreme situations, audacious interventions can stave off disaster for endangered species. Unfortunately, the need for them will only rise.

Bushfires are natural in Australia, but their frequency and intensity are predicted to increase as the climate warms. Alpine ecosystems in particular require a long time to recover, especially from consecutive burns. In 2003, for instance, bushfires burned right over the top of Mount Blue Cow. Twisting, skeletal forms still writhe among the boulders—the bleached bones of mountain plum-pine, another favored food source for the possums. Broome transplanted seedlings to replace them, but two decades later, even though the recent fires spared Mount Blue Cow, they’re only just beginning to take.

Then there’s the snow—the emblem of the high country, and the source of the water that feeds the fens and the streams. Snow depth and the number of snow days have been declining in Australia since the 1950s, and climate scientists warn that, by the end of the century, the Snowy Mountains may no longer live up to their name.

“The outlook for the alpine zone as we know it is pretty bleak,” says ecologist Lesley Hughes, an emeritus professor at Sydney’s Macquarie University, IPCC report author and director of the Climate Council of Australia. Even before it’s gone completely, dwindling snow cover will disturb the possums’ winter rest. A thicker layer of snow provides more insulation; without it, the animals’ nests get colder, which could wake them from hibernation before moths arrive or seeds are available, Broome says. Snow is also a barrier to predators, and warmer winters allow feral cats and foxes to range more freely and hunt possums more easily. In 2002, Broome asked rangers to start trapping and killing cats at Mount Blue Cow. They caught 30 that first winter.

The mountain pygmy possum is often ranked among the Australian species most vulnerable to climate change: Global efforts could still restrain rising temperatures, but the possums’ high-altitude home has already begun its transformation. Even if conservationists continue to intervene with supplementary food when necessary—without snow, without moths, ravaged by fire and cats… Is its extinction inevitable?

The pygmy possums’ deep past offers a glimmer of hope. Paleontology reveals animals and ecologies in the fourth dimension—time. And some scientists believe that insights from the fossil record can offer surprising, if drastic, solutions to the environmental problems we face today.

I meet Michael Archer at his paleontology lab at the University of New South Wales in Sydney. Mounted mammal skeletons line the walls, and the benches are piled with academic tomes, jars of paintbrushes, bottles of acetone, fossilized skulls, and partially-prepared snake vertebra. Today, there is also a live ringtail possum in a box; Archer rescued it from the university cafeteria this morning when he stopped by to grab his coffee.

Now in his 70s, Archer was born in Sydney, but grew up “among hillbillies” in upstate New York, where he learned to make moonshine and play the banjo. When he was 11, he saw some strange shapes poking out of a shed-sized lump of siltstone not far from his house, and chipped bits off it with a sledgehammer and chisel. Inside, he discovered a trove of 370-million-year-old fossils, including trilobites. He packed them into a suitcase and took the steam train to New York City for identification at the American Museum of Natural History. Like dinosaur-loving 11-year-olds everywhere, Archer was hooked. “Most kids get over it,” he says. “Some don’t.”

He moved back to Australia in his 20s, and since 1976 has led excavations of the extensive fossil deposits at Riversleigh in remote northwest Queensland. As he shows me around his lab, Archer points out hunks of Riversleigh limestone bathing in vats of acetic acid, the stone gradually dissolving to reveal the bones within. I see the spine of a giant flightless bird erupting from a rock. “Every one of these is a treasure chest,” he says.

One of those treasures is Burramys. Archer’s team has found more than 500 pygmy-possum bones in Riversleigh rocks 25 to 12 million years old, mainly jawbones and that distinctive, saw-shaped tooth. The fossils are practically identical to the bones of modern mountain pygmy possums. Yet when these ancient ancestors lived, northwest Queensland was carpeted in lush, lowland rainforest. The marsupials’ specially-ridged premolar allowed them to scurry around on the ground, cracking open nuts and seeds: filling a niche unoccupied by any other mammal.

It was such a successful strategy that the possums stuck with it, changing barely at all over 25 million years, through numerous wild swings in Earth’s climate. Around 12 million years ago, the Riversleigh rainforest dried out, and the possums disappear from the record there. “The animals that couldn’t hack it died. But Burramys is a scrubber,” says Archer. “It’s a survivor.”

Fossil Burramys then show up elsewhere in eastern Australia. Around 2 million years ago, the rainforests spread all the way into today’s alpine areas. When the trees retreated, the continent dried out, and, later, settlers cleared the remaining forests for agriculture, Burramys got stranded in the mountains. But by diving into the rockpiles, hibernating over winter, and eating whatever food was available, the species held on.

All this led Archer to believe that Burramys’ comfort zone is actually the rainforest, and that their latent genetic adaptability may allow them to thrive there once again—a theory that he and collaborators are now putting to the test.

At Lithgow in the Blue Mountains, 145 kilometers (90 miles) west of Sydney, and 950 meters (3,100 feet) above sea level, 14 mountain pygmy possums scamper in cages at a special breeding center under the watchful eye of owner Trevor Evans. Evans teamed up with Archer and Hayley Bates to design the breeding facility, which opened in September 2022. It’s part of the wider Secret Creek Sanctuary, which Evans manages and which hosts a variety of native animals from tiny feathertail gliders to koalas, emus, and Tasmanian devils.

Inside the breeding facility, there are 16 separate pygmy-possum enclosures—enough to house 100 animals. Each features nesting tunnels enclosed in man-made rocky outcrops, while wall-stickers of snow-covered Kosciuszko attempt to make the possums feel at home. Water trickles down the rock faces, keeping the environment cool. As soon as Evans turned the watering system on, the possums “started to bonk like mad,” says Archer—their mating instincts apparently triggered by the moisture. When I visit in November, Evans pulls out a small drawer in the fake rock wall to show me where the possums nest. To his surprise, all that “bonking” has already produced results: Inside the woven stringybark is a mother possum with three tiny, near-blind joeys—the first evidence of successful breeding at the new facility.

“The animals that couldn’t hack it died. But Burramys is a scrubber,” says Archer. “It’s a survivor.”

— Michael Archer, University of New South Wales

That promising start has continued, with more joeys born in the months since. And there’s other, contemporary evidence that the plan might work. At Cabramurra, one community of possums lives at just 1,225 meters (4,000 feet) above sea level, lower than any other populations. Snow is inconsistent there, suggesting that the pygmy possums may not require it. In fact, Bates’ doctoral studies suggest that a key limiting factor for possum populations is a permanent supply of fresh water. Hibernation is hard on the kidneys, and the animals seem to need to drink as soon as they emerge from torpor. In the high country, snow provides both water and insulation against the cold; at these lower elevations, a cool, sheltered rocky creek could become a suitable home for mountain pygmy possums.

At the breeding center, Evans and a series of Archer and Bates’ students will monitor the captive possums over the next few years. They’re curious to see whether they will still hibernate, given the slightly warmer temperatures and lack of snow. They’ll also begin to introduce them to lowland food sources and other animals. Eventually, the team plans to release them into Secret Creek’s fenced sanctuary, and then into sufficiently damp, sheltered spots in the wilds of the Blue Mountains. “What we need to do is basically knock on their genetic door and say, ‘Hey, wake up! You have the resilience to adapt to this,” Archer says.

Introducing novel species into ecosystems can be fraught, but Archer is optimistic the little marsupials won’t have a negative impact. Their original ground-dwelling, seed-eating rainforest niche remains vacant, he says, like an empty glove missing its “ghost hand.” To make sure, the scientists will closely monitor ecosystem interactions during the trial releases in fenced areas, and adjust the plan based on their findings.

Broome supports the effort. She also remains skeptical about the possums’ prospects in the lowlands. Temperate rainforests also experience drought and bushfire, she points out—80 percent of the Blue Mountains World Heritage Area burned during the “Black Summer” of 2019-2020—“and they’re riddled with feral cats,” a threat that didn’t exist prior to European colonization.

But Archer believes conservation in the Anthropocene requires radical thinking—and radical action. “We’ve created a situation where we no longer have the luxury of preservation. We have to think about these strange strategies, because there may not be any other solutions. In many cases, that means moving things from what are increasingly unacceptable habitats, to places where they could survive.”

One full-moon night in the Snowy Mountains in March 1834, Aboriginal women performed a song ceremony, in a place now called Dalgety. “Gundji gawalgu yuri,” they sang, in a language that would itself almost be lost in the ensuing century. “Gaba gumadji gugu.

Watching the women sing and beat skin drums that early autumn night was a traveling European botanist named Johann Lhotsky. He noted down the melody, and likely asked for help to record the words. Several weeks later, in Sydney, he worked with three “musical gentlemen” to write up sheet music, arranging it for voice and piano forte in the English parlor ballad style. This “Song of the Women of the Menero Tribe”—Menero, now spelled Monaro, is the plateau to the east of the Snowy Mountains—is the first known piece of music ever printed in Australia.

Aboriginal Australians have been singing songs of the high country for millennia—its snows and its possums, its caves cloaked with moths. In their ancient cultures, story and song have the literal power of creation; songlines trace the movements of ancestral beings as they made the landscape, and encode navigational information and traditional knowledge about animals and plants.

Those singing women might have been Jakelin Troy’s people, her own Ngarigu ancestors possibly among them. Working with a musicologist, she gleaned the song’s story from fragments left in the historical record, and got closer to its original sound by removing European embellishments from the music. While other Aboriginal groups interpret the song’s lyrics differently, Troy thinks that given the time of year it was performed—just at the moment when the bogong moths begin to leave the mountains and return to the plains—it’s possible the song was part of a ceremony to ensure the snows came and the moths returned the following spring. When she compared the lyrics to the words for snow and Moon in Ngarigu glossaries collected by Lhotsky and other European travelers, as well as her knowledge of neighboring Aboriginal languages and grammar, the meaning seemed clear to her: Send the snow for us soon. Moon, make it snow.

For now, it still snows in the Australian Alps. A late blizzard delayed Broome’s November survey, and blocked access to the highest boulder fields. The moths are beginning to return, too. In late 2022, after three years of record-breaking rains, moths once again tiled the caves at Mount Gingera—in numbers approaching half of what they were before the drought.

In early April, the Austral autumn, Troy returned to Dalgety with a group of Ngarigu people. As the fat little possums snuggled into their rocky nests and prepared to hibernate through the winter, as the bogong moths consulted the stars and began their long journey to the north, the people sang the ancient song to life—caring for their Country, singing the animals onward, calling forth the last of the winter snows.

Kate Evans

Kate Evans

Kate Evans is a freelance journalist who lives by the sea in rural New Zealand, but has also called Australia home. She is a regular contributor to New Zealand Geographic, Scientific American, and bioGraphic, and writes about the intersections between nature and culture. You can follow her on Twitter @kate_g_evans.

Alex Pike

Lauren Owens Lambert

Alex Pike is an award-winning photographer, videographer, and writer who likes to document things to do with ecological relationships, conservation, scientific research, and other human interactions with nature. His work has been published in various print and online publications throughout Australia and internationally.



bioGraphic is powered by the California Academy of Sciences, a renowned scientific and educational institution dedicated to regenerating the natural world through science, learning, and collaboration.