Mountain pygmy-possum  (Burramys parvus)

Classified as Critically Endangered (EN) on the IUCN Red List (1).

The largest of the pygmy-possums, the mountain pygmy-possum was only known from fossil records until it was discovered in the Australian Alps in 1966. This small marsupial has fine dense fur, which is grey on the back and a creamy colour underneath. Males develop a more fawn-orange coat during the breeding season. The tail is prehensile and, at up to 16 centimetres, is longer than the body (2) (3).

Found in three geographically isolated populations in south east Australia: two in Victoria in the Mt. Bogong - Mt. Higginbotham range and at Mt. Buller, and the other in Kosciuszko National Park, New South Wales (3) (4).

Inhabits mountain summits at elevations of between 1,500 and 2,228 metres, where there are rock screes and boulderfields. This species is usually associated with mountain plum-pine (Podocarpus lawrencei) heathland and adjacent alpine communities, and is the only Australian mammal confined to alpine environments (1) (2).

Unlike most possums, the mountain pygmy-possum is mainly terrestrial, although it is also an adept climber. Living at high altitude, the mountain pygmy-possum hibernates during the winter months from March / April to September / October. To survive hibernation these possums put on large amounts of fat and then roll into a ball to conserve heat, while snow cover also provides important insulation. During the winter, like all hibernators, individuals regularly arouse for short periods from torpor, and will occasionally move to more suitable hibernacula sites (5). The mountain pygmy-possum stores seeds in caches in captivity, but does not appear to feed during the winter hibernation period in the wild (5). Possums are nocturnal and during the 'active season', which runs from October to April, will feed primarily on the high energy Bogong moth (Agrotis infusa), which arrives in the Australian Alps in large numbers in the summer months to aestivate in the cool rock crevices of the boulderfields. As numbers of these moths decrease in the late summer and autumn, the pygmy-possum switches its diet to seeds and berries, cracking open the hard cases with its large, specialised premolar tooth (1) (2) (3) (4).

Females occupy overlapping home ranges, whereas most males disperse from the natal range and are more nomadic. Breeding coincides with snow melt and the entry of Bogong moths into the boulderfields, usually during September to November. The female mountain pygmy-possum gives birth to up to eight young, although only four survive to be carried in the pouch. Born at an immature stage of development, after a gestation period of 13 to 16 days, the young make their way to the pouch and attach to one of four teats, leaving the pouch after around three weeks to stay in a nest constructed from grasses and moss. The young are weaned by around nine weeks, but the female normally has only one litter a year due to the need to store up fat for winter hibernation (1) (2) (3) (4). The mountain pygmy-possum can live for as long as 12 years (3) (4).

Due to the restrictions of its habitat requirements, the mountain pygmy-possum has suffered from the development of the ski industry in the Australian Alps. A further threat comes from habitat loss caused by increased temperatures and decreasing snow cover as a result of global warming, while predation by the red fox (Vulpes vulpes) and feral cats is also a problem (1) (2) (3) (4). Bushfires in 2003 damaged large areas of habitat (2), and the mountain pygmy-possum’s main prey, the Bogong moth, also faces a number of threats, including pesticide use in its breeding grounds (2) (3). The mountain pygmy-possum occupies just a tiny area, estimated at less than seven square kilometres, and its populations are highly fragmented, putting it at particular risk (1) (4).

The entire range of the mountain pygmy-possum occurs within protected areas, although important parts of these are in ski-resort lease areas. Management plans for the species have been put in place in Victoria and New South Wales, and a national recovery plan is currently being prepared (1). A range of conservation measures have been recommended for this small possum, including protection and restoration of the remaining habitat, population and habitat monitoring, predator control, measures to protect the possums in ski resorts, further research, and captive breeding programmes (1) (3) (4).

View information on this species at the UNEP World Conservation Monitoring Centre.

To find out more about the mountain pygmy-possum see:

• Department of the Environment, Water, Heritage and the Arts. (2009) Burramys parvus - Mountain Pygmy-possum. In: Species Profile and Threats Database. Department of the Environment, Water, Heritage and the Arts, Canberra. Available at:
  http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=267
• Australian Threatened Species: Mountain Pygmy-possum Burramys parvus:
  http://www.environment.gov.au/biodiversity/threatened/publications/pubs/tsd05mountain-pygmy-possum.pdf
• EDGE of Existence:
  http://www.edgeofexistence.org/mammals/species_info.php?id=28