Mountain Pygmy Possum
The Mountain Pygmy Possum is the largest of Australia 's five species of pygmy possum. They are small, mouse-sized nocturnal marsupials which are approximately 11cm long. They have a prehensile tail longer than their head and body combined. Their tail measures almost 14cm. They weigh around 45gm.
The Mountain Pygmy Possum have dull grey-black fur on their back and a cream coloured underbelly. They also have cream fur on their chin and cheeks. The males are slightly larger than the females and their body fur becomes more orange during the breeding season. There is no fur on their pink coloured tail and feet.
They have very dexterous front feet for gathering food, and gripping hind feet. They use their front teeth to scrape at food and they have specialised premolar teeth for cracking and de-husking seeds.
Female Mountain Pygmy Possums they have a pouch containing four teats on the underside of their bodies.
The Mountain Pygmy Possum is found in alpine rock screes and boulder fields where they live among the rock crevices and boulder fields associated with the mountain plum pine (Podocarpus lawrencei). They live mainly in southern Victoria and around Mount Kosciusko in New South Wales and live at altitudes ranging from 1400m to 2200m above sea level. This environment is very cold and the Mountain Pygmy Possum go into a type of hibernation when it gets too cold. They are Australia 's only hibernating marsupials. During hibernation the possum's metabolic rate is reduced by about 98%.
At the beginning of winter hibernation might last for several days before the hungry possum wakes to eat from its food cache - a storage facility rare among marsupials. This initial hibernation period is extended as the winter progresses. The Mountain Pygmy Possum's hibernation periods can last as long as three weeks during the coldest months. There is some evidence obtained from animals the pygmy possums in captivity that they might huddle together for warmth in the wild. Mountain Pygmy Possums can be found beneath deep snow and in boulder crevices.
Mountain Pygmy Possums are ground-dwelling, nocturnal marsupial that sleep in a nest during the day.
The Mountain Pygmy Possum eats insects, fleshy fruits, nuts, nectar and seeds. During the short alpine spring and summer months they feed on insects including Bogong Moths (Agrotis infusa). At other times of the year they are more opportunistic, supplementing their insect diet with the seeds and the fruit of plants like the mountain plum pine, rambling bramble and snow beard-heath. During their hibernation in the snow season, between April and October, the possums feed from a hidden cache of stored seeds and nuts.
For most of the year, males and females live apart from each other. The females live on the better part of the rocky slopes, while the males live on the margins, usually lower on the mountain. In order to breed the males migrate to the female's habitat. However, on Mount Higginbotham , the males had to cross a road at the peak of the ski season and their survival was put in danger. To solve the problem, a "Tunnel of Love" was constructed under the road and a road sign was put in place to warn drivers.
The mating season occurs from November to the end of December. A litter usually produces four young in a season. The young leave the pouch at around three weeks even although their eyes don't open until the fifth week. When the young leave the pouch their mother builds them a nest of grass. The young are fully grown by about five months. Females reach reproductive maturity in their first year, some males take up to two years to reach reproductive maturity.
Wild Mountain Pygmy Possums live for up to four years, in captivity they can live for about six years. There have been reports of some females reaching an age of more than 12 years this would make them the longest-living small terrestrial marsupial known. In 1991, 80% of the breeding adults were estimated to be females. This may be due to the fact that adult females permanently inhabit the best locations on the rocky slopes while the males live on the margins. The areas occupied by the females can support a greater population and they have a better chance than the males of surviving more than one season.
Female Mountain Pygmy Possums are quite sociable, sharing a daytime nest site (probably with related females), and dispersing at night to forage. Males are solitary, and move over large areas, being repelled by unreceptive females whose ranges they cross. This leads to males being less likely than females to survive in a given year as they are more exposed to predators, and do not share body heat during the winter.
The rare Mountain Pygmy Possum is the only permanent alpine mammal. It is the only existing species in the Burramys genus.
Status and Threats
Classified as Endangered (EN - B1+2abcde) on the IUCN (International Union for the Conservation of Nature) Red List 2002.
The Mountain Pygmy Possum was first described as a Pleistocene fossil by Robert Broom in 1896. It was thought to be extinct until 1966, when a living specimen was discovered in a ski-hut on Mount Hotham .
As of 1992, there were two geographically isolated populations; the area covering Mount Bogong , Mount Higginbotham and Mount Hotham in Victoria , and Kosciusko National Park in New South Wales . The possum's entire range is roughly in the same area as Australia 's ski fields and is thought to cover less than 10 square kilometres. This does not include an area around Mt. Buller and Mt. Stirling where the Mountain Pygmy Possum was discovered recently – this area is yet to be fully investigated. (Maxwell et al. 1996).
To further preserve the Mountain Pygmy Possum, a small proportion of the Perisher Blue Ski Resort in New South Wales has been declared ‘out of bounds' to prevent resort guests (skiers and snowboarders) from disturbing the possums during their hibernation.
Long-term climate changes have probably caused its overall decline. Factors caused by man include habitat loss through ski resort development and predation by introduced cats and foxes. There are also possible impacts associated with 100 years of vegetation modification caused by grazing and burning in alpine and subalpine areas.
It is estimated that the entire population of the Mountain Pygmy Possum is less than 3000 individuals.
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