The Goulburn Broken Catchment Management Authority is highlighting the importance of tree hollows for wildlife in its 2025 Year of the Tree Hollow community awareness campaign. This month, the Sugar Glider (Petaurus breviceps) and the Squirrel Glider (Petaurus norfolcensis) are featured.
Named for its fondness for sugary sap and nectar, the nocturnal Sugar Glider spends much of its arboreal nightlife leaping and gliding in search of food and nesting hollows.
Goulburn Broken CMA project officer, Janice Mentiplay-Smith, said as with all gliders, the Sugar Glider had a membrane extending between its ankles and wrists.
“Upon leaping from a branch, the Sugar Glider extends its limbs to open this ‘parachute’,” Ms Mentiplay-Smith said.
“It may glide for up to 50-80 metres or further depending on the height of the tree from which it alights and the surrounding topography, using its long tail as a rudder.
“Unlike a bat or bird, the Sugar Glider is not capable of sustained flight, however its ability to glide is a unique adaptation to an arboreal life.”
Females give birth in winter and spring after just 15-17 days gestation when one or two joeys weighing an incredible 0.2 grams are born. Using their acute sense of smell, the tiny joeys crawl towards the scent gland in their mother’s pouch where they remain safely cocooned, consuming milk for 60 days. During the colder months, the Sugar Glider enters a state of torpor, a form of short-term hibernation, whereupon it minimises energy consumption by curling into a tiny ball and reducing breathing and body temperature.
Although it shares the same environment and similar features and habits to the Sugar Glider, the Squirrel Glider is identifiable by its larger size.
“As with the Sugar Glider, it is a gliding marsupial that lives a nocturnal life amongst the treetops. It too is dependent upon tree hollows; however, it has adapted to utilising nest boxes where natural tree hollows are lacking,” Ms Mentiplay-Smith said.
“If you live in a woodland or forested area, installing nest boxes on your property is one of the most immediate ways you can benefit hollow dependent wildlife.”
The Squirrel Glider covets the sugary nectar and sap that packs a carbohydrate punch and readily uses its sharp teeth to pierce tree trunks to cause the sap to ooze. Insects, bird eggs and small nestlings are also on the menu. Its natural predators include goannas, carpet pythons, owls and kookaburras, demonstrating their importance in the food chain.
The Squirrel Glider produces one or two joeys after just 18 days gestation. The young remain in their mother’s pouch for around three months and wean at four months, becoming independent at around 10 months of age.
“The Squirrel Glider faces the same threats as its sugary cousins - cats, foxes and barbed wire fences that snag their delicate gliding membrane, as well as habitat loss and degradation, loss of hollow-bearing trees and understorey food plants, inappropriate fire regimes and the occupation of existing tree hollows by aggressive species such as the European Honeybee and Indian/Common Myna.
“As the incremental loss of large old trees containing hollows continues across the landscape, the Squirrel Glider is forced to occupy dangerous roadsides where large old trees remain, increasing the risk of vehicle collision.”
Read more about the Sugar Glider, Squirrel Glider and other mammal species in the Goulburn Broken catchment in The Mammal Book: The Mammal Book - GB CMA - Goulburn Broken CMA
The Year of the Tree Hollow is supported by the Victorian Government through the Our Catchments Our Communities stewardship program.
Sugar Glider in a nestbox- Russel Jones
Squirrel Glider at Moonlit Sanctuary, Victoria. Source: Museums Victoria. Photographer: D Paul.