The sugar glider (Petaurus breviceps) is a small, omnivorous, arboreal gliding possum belonging to the marsupial infraclass. The common name refers to its preference for sugary nectarous foods and ability to glide through the air, much like a flying squirrel. Due to convergent evolution, they have very similar appearance and habits to the flying squirrel, but are not closely related. The scientific name, Petaurus breviceps, translates from Latin as “short-headed rope-dancer”, a reference to their canopy acrobatics.
The sugar glider is native to eastern and northern mainland Australia, and was introduced to Tasmania. It is also native to various islands in the region.
Sugar gliders can be found throughout the northern and eastern parts of mainland Australia, and in Tasmania, Papua New Guinea and several associated isles, the Bismarck Archipelago, Louisiade Archipelago, and certain isles of Indonesia, Halmahera Islands of the North Moluccas. The sugar glider was introduced to Tasmania in 1835. This is supported by the absence of skeletal remains in subfossil bone deposits and the lack of an Aboriginal Tasmanian name for the animal. They can be found in any forest where there is a suitable food supply, but most are commonly found in forests with eucalyptus trees. Being nocturnal, they sleep in their nests during the day and are active at night. During the night they hunt insects and small vertebrates, and feed on the sweet sap of certain species of eucalyptus, acacia and gum trees.
They are arboreal, spending most of their lives in trees. When suitable habitats are present, sugar gliders can be seen 1 per 1,000 square metres, provided there are tree hollows available for shelter.
Appearance and Anatomy
This male’s forehead bald spot is a scent gland. The eyes are adapted for night vision and the ears swivel. The sugar glider has a squirrel-like body with a long, partially (weakly) prehensile tail. The males are larger than the females and have bald patches on their head and stomach; their length from the nose to the tip of the tail is about 24 to 30 cm (12–13 inches, the body itself is approx. 5–6 inches). A sugar glider has a thick, soft fur coat that is usually blue-grey; some have been known to be yellow, tan, or albino. A black stripe is seen from its nose to midway on its back. Its belly, throat, and chest are cream in colour.
Being nocturnal, its large eyes help it to see at night, and its ears swivel to help locate prey in the dark.
It has five digits on each foot, each having a claw, except for the opposable toe on the hind feet. Also on the hind feet, the second and third digits are partially syndactylous (fused together), forming a grooming comb. Its most striking feature is the patagium, or membrane, that extends from the fifth finger to the first toe. When legs are stretched out, this membrane allows the sugar glider to glide a considerable distance.
There are four scent glands, located frontal (forehead), sternal (chest), and two paracloacal (associated with, but not part of the cloaca). These are used for marking purposes, mainly by the male. The frontal gland is easily seen on an adult male as a bald spot. The male also has a bifurcated (two shafts) penis. The female has a marsupium (pouch) in the middle of her abdomen to carry offspring.
Head-body length: 170 mm (160-210)mm Tail length: 190 mm (165-210)mm Weight, males: 140 grams (115-160)g, females: 115 grams (95-135)g Heart rate: 200-300 beats per minute, respiration: 16-40 breaths per minute Lifespan: in the wild, up to 9 years; typically up to 12 years in captivity; in zoos, maximum reported is 17.8 years.
Sugar Gliders are highly social animals. They live in family groups or colonies consisting of up to seven adults, plus the current season’s young which leave as soon as they are able to, all sharing a nest and defending their territory, an example of helping at the nest. They engage in social grooming, which in addition to improving hygiene and health, helps bond the colony and establish group identity.
A dominant adult male will mark his territory and members of the group with saliva and a scent produced by separate glands on the forehead and chest. Intruders who lack the appropriate scent marking are expelled violently. Each colony defends a territory of about 2.5 acres where eucalyptus trees provide a staple food source. Within the colony, typically no fighting takes place beyond threatening behaviour.
The sugar glider is not considered endangered, and its conservation rank is “Least Concern (LC)” on the IUCN Red List. Despite the loss of natural habitat in Australia over the last 200 years, it is adaptable and capable of living in small patches of remnant bush, particularly if it does not have to cross large expanses of cleared land to reach them. However, several close relatives are endangered, particularly Leadbeater’s Possum and the Mahogany Glider.
Conservation in Australia is enacted at the federal, state and local levels, where sugar gliders are protected as a native species. The central conservation law in Australia is the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The National Parks and Wildlife Act 1974 is an example of conservation law in the state of South Australia, where it is legal to keep (only) one sugar glider without a permit, provided it was acquired legally from a source with a permit. A permit is required to obtain or possess more than one glider, or if one wants to sell or give away any glider in their possession. It is illegal to capture or sell wild sugar gliders without a permit.
Diet and Nutrition
Sugar gliders are seasonally adapted omnivores with a wide variety of foods in their diet. In summer they are primarily insectivorous, and in the winter when insects are scarce, they are mostly exudativorous (feeding on acacia gum, eucalyptus sap, manna, honeydew or lerp). They are opportunistic feeders and can be carnivorous (preying mostly on lizards and small birds), and eat many other foods when available, such as nectar, acacia seeds, bird eggs, pollen, fungi and native fruits.
In captivity, they can suffer from calcium deficiencies if not fed an adequate diet. A lack of calcium in the diet causes the body to leach calcium from the bones, with the hind legs first to show noticeable dysfunction. Calcium to phosphorus ratios should be 2:1 to prevent hypocalcemia, sometimes known as hind leg paralysis (HLP). Their diet should be 50% insects (gut-loaded) or other sources of protein, 25% fruit and 25% vegetables. Some of the more recognised diets are Bourbon’s Modified Leadbeaters (BML), High Protein Wombaroo (HPW) and various calcium rich diets with Leadbeaters Mixture (LBM).
Biology and Behaviour
The sugar glider is one of a number of volplane (gliding) possums in Australia. This remarkable ability to glide is achieved through flaps or membranes of loose skin (patagia) which extend between the fifth finger of each hand to the first toe of each foot. The animal launches itself from a tree, spreading its limbs to expose the gliding membranes. This creates an aerofoil enabling them to glide 50 metres or more. This gliding flight is regulated by changing the curvature of the membrane or moving the legs and tail.
This form of arboreal locomotion is typically used to travel from tree to tree; the species rarely descends to the ground. Gliding serves as an efficient means of both locating food and evading predators.
During the cold season, drought, or rainy nights, a sugar glider’s activity is reduced. The animal may even become immobile and unresponsive due to torpor. This differs from hibernation in that torpor is usually a short-term daily cycle. In the winter season or drought, there is a decrease in food supply, which is a challenge for this marsupial because of the energy cost for the maintenance of its metabolism, locomotion, and thermoregulation. With energetic constraints, the sugar glider will enter into daily torpor for 2–23 hours while in rest phase. However, before entering torpor, a sugar glider will reduce activity and body temperature normally in order to lower energy expenditure and avoid torpor.
Torpor, which is seen as an emergency measure, saves energy for the animal by allowing its body temperature to fall to a minimum of 10.4 °C (50.7 °F) to 19.6 °C (67.3 °F). When the food is scarce, as in winter, heat production is lowered in order to reduce energy expenditure. With low energy and heat production, it is important for the sugar glider to peak its body mass by fat content in the autumn (May/June) in order to survive the following cold season. In the wild, sugar gliders enter into daily torpor more often than sugar gliders in captivity.
The age of sexual maturity in sugar gliders varies slightly between the males and females. The males reach maturity at 4 to 12 months of age, while females require from 8 to 12 months. In the wild, sugar gliders breed once or twice a year depending on the climate and habitat conditions, while they can breed multiple times a year in captivity as a result of consistent living conditions and proper diet.
A sugar glider female gives birth to one (19%) or two (81%) babies (joeys) per litter. The gestation period is 15 to 17 days, after which the tiny joey (0.2 g) will crawl into a mother’s pouch for further development. They are born with a continuous arc of cartilage in their shoulder girdle to provide support for climbing into the pouch. This structure breaks down immediately after birth.
It is virtually unnoticeable that the female is pregnant until after the joey has climbed into her pouch and begins to grow, forming bumps in her pouch. Once in the pouch, the joey will attach itself to its mother’s nipple, where it will stay for about 60 to 70 days. The mother can get pregnant while her joeys are still ip (in pouch) and hold the pregnancy until the pouch is available. The joey gradually spills out of the pouch until it falls out completely. It emerges virtually without fur, and the eyes will remain closed for another 12–14 days. During this time, the joey will begin to mature by growing fur and increasing gradually in size. It takes about two months for the offspring to be completely weaned, and at four months, the young glider is on its own.
Around the world, the sugar gliders are popular as a domesticated exotic pet. It is also one of the most commonly traded wild animals in the illegal pet trade, where animals are plucked directly from their natural habitats.
In Australia, sugar gliders can be kept in Victoria, South Australia, and the Northern Territory. However, they are not allowed to be kept as pets in Western Australia, New South Wales, the Australian Capital Territory, Queensland or Tasmania.
Sugar gliders are popular as pets in the United States, where they are bred in large numbers. Most states and cities allow sugar gliders as pets, with some exceptions including California, Hawaii, Alaska, and Massachusetts. Some other states require permits or licensing.