“Its super long fluffy tail gave it away
“The first time I saw one, I was leading a night walk and we heard this big crash in the eucalyptus trees above us,” said Wendy Bithell of Vision Walks Eco-Tours as we strapped on night vision goggles, the nature guide’s secret weapon for spotting nocturnal critters in the rainforests of northern New South Wales (NSW).
“We looked up and its super long fluffy tail gave it away,” added Bithell. “They’re beautiful creatures to look at, but they’re not as graceful as you’d think they might be.”
A solitary, tree-dwelling marsupial with big furry ears, large round eyes and a feather boa-like tail that lives in the eucalypt forests of eastern Australia, the greater glider is often described as a clumsy flying possum. Only cuter.
“They’re like living Muppets,” Australian National University (ANU) ecologist Dr Kara Youngentob told me via Zoom. “Most people are more familiar with sugar gliders [a small, sweet-toothed glider species heavily exploited in the illicit international pet trade] – think of the greater glider as their bigger, lazier, fluffier cousin.”
The greater glider is the only member of the ringtail possum family that doesn’t have a grippy prehensile tail. But it is also unique from its relatives in that it dines exclusively on eucalyptus leaves (like koalas) and has gliding membranes that run only from its elbows to its ankles (unlike its cousins, which have membranes stretching to their forepaws). This allows them to perform more controlled glides and gives them something of a superhero quality in flight.
“When they jump, they put their little arms out in front of them like Wonder Woman,” said Youngentob. Similar to the comic book heroine, the species can also glide long distances – up to 100m between the treetops, where it dens in tree hollows that can take more than a century to form.
Three times cuter
Previously thought to range from the steamy tropical rainforests of Far North Queensland down to the cool, wet forests of Victoria’s Central Highlands, a territory spanning some 3,000km, the greater glider was recently proven to be three distinct species, with the nocturnal marsupials getting smaller the further north they live.
The size variations were noted when greater gliders were first described to science in the 1800s (by Scottish scientific writer Robert Kerr in a 1792 paper building on the work of Swedish botanist and “father of modern taxonomy” Carl von Linné), but it was assumed the specimens were one species (Petauroides volans) that grew bigger at lower latitudes to conserve heat, a theory known as Bergmann’s rule.
James Cook University researcher Denise McGregor, who led the study published in November 2020, tested this theory as part of her PhD, with genetic material taken from greater gliders in northern Queensland (which grow to the size of a small ringtail possum) proving that it was a different species to the cat-sized southern species found south of the Tropic of Capricorn (which the scientific name name, Petauroids volans, now refers to. But that wasn’t the only discovery she’d make.
“By then another group – Jackson and Groves – had published a book about gliding mammals [Taxonomy of Australian Mammals (2015)] in which they proposed that there were three separate species,” said McGregor. “So, I thought I’d better take some samples from where they thought the third species lived [in mid-Queensland, west of Mackay up to Townsville], and sure enough we came back with three species.”
Little is known about the central species (Petauroides armillatus) and the northern species (Perauroides minor; whose territory is thought to extend to just north of Cairns), with the thrill of the discovery tempered by its implications for conserving the species.
While understanding the ecology of a species is important for the development of conservation management, said Youngentob, who co-authored the study, dividing the greater glider into three species means there are fewer of them left to protect.
“We already had the new species data before last summer’s bushfires, so when the entire southern greater glider habitat was on fire, we were just petrified because we knew the species didn’t exist anywhere else,” she said.
Yet according to long-term surveys conducted by ANU Professor David Lindenmayer, Australia’s foremost greater glider expert, southern populations had already plummeted by 80% in some areas before the bushfires. This loss is largely attributed to logging, which has wiped out vast swaths of hollow-bearing trees that greater gliders rely on.
Indeed, a 2020 World Wildlife Fund report revealed that destruction of greater glider habitat increased by 52% in NSW and Queensland after the species was listed as vulnerable to extinction by the federal government in 2016.
“Logging doesn’t only destroy greater glider habitat,” said Lindenmayer. “It also makes bushfires burn hotter and changes the composition of the landscape to less palatable food trees.”
Climate change, too, is impacting the species, with rising night-time temperatures – Sydney recorded its hottest November night on record in 2020 – thought to cause greater gliders to lose their appetite, much like humans do in hot weather.
“Greater gliders maintain minimal fat stores so they can’t survive more than a few days without eating,” explained Youngentob. “In some places, the hotter nights are probably killing these animals.”
Saving the greater glider
The bushfires have prompted the federal government to reconsider the conservation status of the greater glider, but researchers argue that more action is needed to protect the species.
“If we don’t stop clearing thousands of hectares of land for coal mining and logging thousands of hectares of forests to generate woodchips, the greater glider is going to become the next koala,” said Lindenmayer, referring to the extinction crisis now faced by the iconic marsupial.
Meanwhile, wildlife organisations along Australia’s eastern seaboard are ramping up efforts to save the species. In mid-2020, the Queensland Glider Network, an arm of the Wildlife Preservation Society of Queensland, launched a greater glider monitoring project in the state’s south-east to help promote conservation awareness. South of the border, conservationists are currently campaigning against planned logging in several northern NSW glider habitats including Bungabbee State Forest north of Casino, where a recent survey organised by the North East Forest Alliance (NEFA) also revealed the previously unknown presence of two vulnerable animals – the long-nosed potoroo and marbled frogmouth.
“We could potentially lose another glider species before we even know it exists
“The area has already been denuded of large hollow-bearing trees so the greater glider population will be in big trouble if they lose what’s left,” said NEFA co-founder Dailan Pugh, whose environmental activism in the 1990s led to the creation of the state’s first endangered fauna species legislation.
In Victoria, conservationists applauded the setting aside of 96,000 hectares of forests in 2019 to help protect greater gliders. But by the new year, around half of the protection area had been decimated by bushfires.
“We could potentially lose another glider species before we even know it exists,” said McGregor.
The new “dark” tourism?
Only active after dark, generally sticking to the treetops and tending to avoid residential areas where larger nocturnal critters such as brushtail possums outcompete them for resources, greater gliders can take some effort to spot. This goes some way to explain why greater glider tourism hasn’t exactly taken off (yet). But seeking out an opportunity to spot these mysterious creatures could contribute to their conservation.
The Wildlife Preservation Society of Queensland runs periodic greater glider spotlighting tours, as does Melbourne-based conservation organisation Greening Australia, with associated costs supporting various conservation programmes. More regular tours are offered by Carnarvon Gorge Eco Tours in central QLD and Faunagraphic Wildlife Tours in the state’s south-east. Go during breeding season (which McGregor thinks may vary between species), and you might be lucky enough to spot a couple intertwining their tails in courtship.
“The southern species comes in different colours, so you often get this cool contrast if you have a light one and a dark one wrapped together,” said Youngentob.
On my own night vision walk, I spy long-nosed bandicoots, pademelons, short-eared possums, bush rats and even a huge rough-scaled snake. But incisions on a tree trunk made by a sap-eating sugar glider is the closest I get to spotting a greater glider, which were once a common feature of my local rainforests.
“It has been quite a while now since I’ve seen one,” Bithell rued, “but when we do, it’s a relief to know that they’re still out there.”
Nature’s Curiosities is a BBC Travel series that offers a close-up look at the natural world, taking adventurous travellers on an unexpected journey of exploration.
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www.bbc.com 2021-02-18 20:15:21