Miscellaneous mammals 2: The Sugar Glider

In Twilight World, our nocturnal house, one of the more easily overlooked species are our Sugar Gliders, Petaurus breviceps, of which we currently have 6. This is about the only commonly seen gliding mammal to be found in the world’s zoos, and is also widely known in the pet trade, but there are a few other species in its genus and some more distantly related forms may be found in some collections. Currently there are 6 species in Petaurus, but this may change (see below),

The feature of Sugar Gliders that give them their name is the patagium, a flap of skin between the front and hind legs which stretches out to form a gliding membrane when the animal jumps from a tree, either to travel between trees or to escape from a predator. If the wind is right, a sugar glider can travel as much as 100m in a single glide, although 10m or so is more usual. Sugar gliders are small mammals, about 40cm long, of which more than half is tail. The weight is 100g – 150g, with males weighing more.

Despite their dormouse-like appearance, Sugar Gliders are marsupials, and have a pouch in which the females keep the young (called joeys) until they are independent. As with many marsupials, the males have a bifurcated penis. They usually live in family groups, which maintain their collective identity be mutual scent marking. Strangers without the colony scent will be attacked. Natural enemies are what you would expect – predatory birds (especially owls), snakes, monitor lizards, plus introduced carnivores such as cats (although gliders would only be vulnerable if they were on the ground).

Studying small nocturnal mammals is a difficult task, but indications are that at least P.breviceps is capable of using secondary or degraded forest as well as primary rainforest. They can live at comparatively high densities – about 1 animal per hectare has been reported for P.norfolcensis, and all the species seem to have a similar diet in the wild of sap, gum, and other plant exudates, plus some invertebrates as a source of protein. It is quite likely that they also take birds eggs when they find them as well.

A diet of gum requires a specialised intestinal tract – gums usually contain complex carbohydrates which require a specialised gut flora to adequately digest. In fact, their diet closely resembles the marmosets and tamarins of South America, although the latter are diurnal. Like the marmosets though, they like to sleep in holes in trees, and I suspect the distribution of suitable nest holes is probably a major limiting factor in the population.

P.breviceps ranges from the Moluccan islands in the west, through Papua New Guinea, and down the coastal forests of eastern Australia to as far south as Tasmania. With such a vast range, there must be a strong suspicion that the taxonomy actually comprises a species complex, possibly with varied ecology, diet, and behaviour, especially in the colder parts of its range. This is a very common situation with nocturnal animals – they tend to differ in calls (all known Petaurus species are highly vocal), habitat choice, or even scent, which means that without intensive DNA investigation the true extent of their diversity remains unknown.

P.breviceps is currently listed as of Least Concern on the IUCN Red data list, but with the current state of taxonomy this may conceal several island endemic forms which are in a more serious case. The origin of the form being bred for the pet trade is unknown, but probably includes one or more islands in Indonesia or Papua New Guinea. There is thus a strong possibility that the domestic form is actually a hybrid of several subspecies or species.

Although undeniably attractive, sugar gliders do not make good pets, especially for people who do not understand their requirements. As a marsupial with a specialised diet their care and hygiene is not at all like the small rodents they superficially resemble, and as a highly active, social, arboreal animal they need large (aviary-sized) quarters, a cohesive social group, and appropriate heating. Our sugar gliders live in an enclosure of about 2.5m x 2.5mx 4m, and could easily make use of a much larger space. Incidentally, they share it with our pair of Long-nosed Potoroos, of which more next week.

(images from australianfauna.com)