The sugar glider (Petaurus breviceps) is a small, omnivorous, arboreal, and nocturnal gliding possum. The common name refers to its predilection for sugary foods such as sap and nectar and its ability to glide through the air, much like a flying squirrel. They have very similar habits and appearance to the flying squirrel, despite not being closely related—an example of convergent evolution. The scientific name, Petaurus breviceps, translates from Latin as "short-headed rope-dancer", a reference to their canopy acrobatics. The sugar glider is characterised by its pair of gliding membranes, known as patagia, which extend from its forelegs to its hindlegs. Gliding serves as an efficient means of reaching food and evading predators. The animal is covered in soft, pale grey to light brown fur which is countershaded, being lighter in colour on its underside. The sugar glider, as strictly defined in a recent analysis, is only native to a small portion of southeastern Australia, corresponding to southern Queensland and most of New South Wales east of the Great Dividing Range; the extended species group, including populations which may or may not belong to P. breviceps, occupies a larger range covering much of coastal eastern and northern Australia, New Guinea, and nearby islands. Members of Petaurus are popular exotic pets.
Taxonomy and evolution The genus Petaurus is believed to have originated in New Guinea during the mid Miocene epoch, approximately 18 to 24 million years ago. The modern Australian Petaurus, along with New Guinean members of what were formerly considered P. breviceps, diverged from their closest living New Guinean relatives ~9-12 mya. They probably dispersed from New Guinea to Australia between 4.8 and ~8.4 mya, with the oldest Petaurus fossils in Australia being dated to 4.46 million years. This may have been possible due to sea level lowering from about 7 to 10 mya, resulting in land bridges between New Guinea and Australia. The taxonomy of the species is complex, and is still not fully resolved. It was formerly understood to have a wide range across Australia and New Guinea, being the only glider to have this distribution, and to be divided into seven subspecies, with three occurring in Australia and four in New Guinea. This traditional subspecific division was based on small morphological differences, such as colour and body size. However, a 2010 genetic analysis using mitochondrial DNA indicates that these morphologically defined subspecies may not represent genetically unique populations. Further studies have found significant genetic variation within populations traditionally classified in P. breviceps, sufficient to warrant splitting the species into multiple. The subspecies P. b. biacensis, from Biak Island off of New Guinea, was reclassified as a separate species, the Biak glider (Petaurus biacensis). In 2020, a landmark study suggested that P. breviceps actually comprised three cryptic species: the Krefft's glider (Petaurus notatus), found throughout most of eastern Australia and introduced to Tasmania, the savanna glider (Petaurus ariel), native to northern Australia, and a more narrowly defined P. breviceps, restricted to a small section of coastal forest in southern Queensland and most of New South Wales. In addition, other sugar glider populations throughout this range (such as those on New Guinea and the Cape York Peninsula) may represent undescribed species or be conspecific with previously described species. This indicates that contrary to previous findings of a large range (which in fact applied to P. notatus and, to a lesser extent, to P. ariel), P. breviceps is a range-restricted species that is sensitive to ecological disasters, such as the 2019-20 Australian bushfires, which significantly affected large portions of its habitat. P. breviceps and P. notatus are estimated to have diverged ~1 million years ago, and may have originated from long term geographic isolation. The early-mid Pleistocene saw an uplifting of the Great Dividing Range, contributing to and coinciding with aridification of the interior of Australia, including on the western side of the range. This, as well as other climactic and geographic factors, may have isolated the ancestors of P. breviceps to refugia on the eastern, coastal side of the Great Dividing Range. This would be an example of allopatric speciation.
Distribution and habitat Sugar gliders are distributed in the coastal forests of southeastern Queensland and most of New South Wales. Their distribution extends to altitudes of 2000m in the eastern ranges. In parts of its range, it may overlap with Krefft's glider (P. notatus). The sugar glider occurs in sympatry with the squirrel glider and yellow-bellied glider; and their coexistence is permitted through niche partitioning where each species has different patterns of resource use. Like all arboreal, nocturnal marsupials, sugar gliders are active at night, and they shelter during the day in tree hollows lined with leafy twigs. The average home range of sugar gliders is 0.5 hectares (1.2 acres), and is largely related to the abundance of food sources; density ranges from two to six individuals per hectare (0.8–2.4 per acre). Native owls (Ninox sp.) are their primary predators; others in their range include kookaburras, goannas, snakes, and quolls. Feral cats (Felis catus) also represent a significant threat.
Appearance and anatomy
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