The page cannot be found

The Greater Glider is cute, but not many people get the chance to see one in the eastern Australian wilds it calls home.  They are shy, solitary and nocturnal, yet one thing is certain – this endangered marsupial species has adorable down to a fine art.  It was, until 2020, believed to be a single species, with variations according to habitat.  After careful research using high-throughput genetic marker techniques, it was discovered that the genus Petauroides was not monotypic – it did not contain a solitary species, after all: there are three species of greater glider. Image

Southern Greater Glider

So, what does one do when this happens?  Keeping things simple and straightforward is always a good plan, so we now have the Northern, Central and Southern greater gliders – named after the regions of the range in which they are found.  Just to make matters a little complicated, each species comes in two forms.  The central greater glider is usually silvery-brown, while the southern greater glider is especially well known for having both dark and pale grey-white forms (the variation seems to be a normal colour morph rather than a sign that they are different sexes or ages. In other words: some are naturally darker, some paler).

Image

The three species are different sizes, too – but this is not easy for the untrained eye to spot.  The southern greater glider (Petauroides volans) is the largest of the three, and is around the size of a house cat (at most 15 inches or 35cm long).  The central (Petauroides armillatus) is a little smaller and the smallest, coming in at about a foot long or 30cm (not counting the tail) is the northern (Petauroides minor).  So, although these lengths are distinguishable, as the species do not live side by side, it’s not difficult to see why they were thought to be the same species for so long, with the variations put down to habitat factors.

Central greater glider (Petauroides armillatus)

Image

 

 The body of the greater glider is made to look a little larger by the fact that their fur is bushy (and up to 2.5 inches long).  The tail seems the bushiest part of all, and is easily as long as the animal, even though it isn’t prehensile. As they glide effortlessly through the forest, greater gliders rely on their long, bushy tails for balance, steering and controlled landings. It’s a built-in stabiliser, effectively. Their large ears are probably the deciding factor in their cuteness quotient, giving them an alert and irresistibly endearing look – like a relative of Gizmo from Gremlins. As they are strictly vegetarian, the ears are not used to hunt, but to try and ensure that they do not become prey. They enable greater gliders pick up every rustle, snap and suspicious sound in the forest. That’s pretty handy when you spend your nights gliding about in the dark.

And, oh boy, can they glide. Here is some spectacular footage, courtesy of the WWF Australia.  The very last glide featured is particularly interesting, as it shows a mother gliding through the canopy with a joey (baby) on her back, and it seems to be practicing its own gliding skills as it clings to her.  The greater glider does not travel along the ground unless it absolutely cannot help it – and if so appear very slow and clumsy.  Yet with wrists tucked under the chin, they glide between the trees in the high canopy with an astonishing grace.  

Watching footage like the video above, it’s easy to think that the greater gliders are closely related to other glider species, such as the well-known sugar glider which is sometimes kept as a pet (although that is now illegal in a number of Australian states and banned or restricted in some US states).  Related they are, but not closely.  The greater gliders diverged from the other gliding marsupials about 36 million years ago. 

Central greater glider - Petauroides armillatus

They have different gliding mechanisms, too.  On the greater glider, the membrane which enables them to glide is positioned between the elbow and the ankle.  This is distinct from its long lost cousins, the other gliding marsupials, that have membranes that stretch from wrist to ankle.  So are they better gliders? Not exactly - just differently engineered. Greater gliders seem built for long, graceful canopy crossings, while their smaller cousins are more like nimble aerial acrobats.

Central greater glider - Petauroides armillatus

We’ve already established that the greater gliders diverged from the other gliders tens of millions of years ago.  Their closest relative is the lemuroid ringtail possum (Hemibelideus lemuroides) and the word closest doesn’t do the distance justice.  The two went their separate ways, evolutionarily, about 18 million years ago.  As such, the three glider species make up their own genus meaning that they have their own distinct scientific group within the animal family tree.

So, how does a greater glider spend its day?  At night, they feed off the young leaves and flowers of a number of eucalyptus trees (a habit they share with the koala). Although this may seem a little fussy, the younger leaves have a higher source of protein than the older ones – and as eucalyptus isn’t a great source of nutrients, they eat only those. 

Once the sun rises, they head for home – and it’s home alone as they are solitary (unless caring for a joey, like the one above - which come along once a year after the female reaches sexual maturity at around the age of two).  Their dens are sometimes lined with leaves and bark they strip off the trees using their claws.  Another strange fact about the greater glider is that the first two toes on its fore foot are opposable, helping it to grip branches securely). 

Their dens are found in the hollows of mature trees, but greater gliders are not exactly minimalists. One animal may use up to 20 different dens, apparently operating on the principle that one simply cannot have too many bedrooms.  It does mean that it can hopefully get inside one of them quickly, away from its main predator, the Powerful Owl (Ninox strenua)), by having a number of dens from which to choose.  

Image

As a quick aside - yes, there really is a bird called the Powerful Owl, pictured above, looking every inch the villain of the piece. Given its size, strength and deeply inconvenient habit of eating gliders, the name feels entirely justified (and very Australian – the name does exactly what it says).

Image Image

Although a major concern for the greater glider, the owl - however powerful - is not the main reason for its decline. That title belongs, depressingly enough, to us. Logging, habitat loss and climate change have all taken their toll, and the catastrophic 2019–20 Australian bushfires only deepened the crisis, tearing through vast areas of forest, including parts of the glider’s protected habitat. Some researchers believe logging may even have made the fires more intense by changing the structure of the forest and reducing suitable food trees. Even so, conservation work is growing, and there is still real hope that stronger habitat protection can give the greater glider (all three species) a fighting chance.  Let’s keep our fingers crossed.