Cercartetus lepidusTasmanian pygmy possum

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Geographic Range

The little pygmy-possum is found in Southeastern Australia from the mallee heathlands of Victoria to the forests of Tasmania. Cercartetus lepidus individuals have also been found on Kangaroo Island. (Burton, 1987)

Habitat

Even though Cercartetus lepidus has a prehensile tail and is an excellent climber, it normally lives close to the ground and stays away from the higher branches of trees. This may abe due to predation by owls (Green, 1983). In Tasmania, C. lepidus is found in tall closed forest to low woodland, in areas with an average rainfall of 300 mm. In mainland Australia and Kangaroo Island, C. lepidus is found from low open woodland to heathlands. The heathlands of Victoria, with an average rainfall of 1200 mm, provide a greater range of food that favors the continous breeding pattern previously mentioned (Ward, 1992).

Physical Description

Cercartetus lepidus is the smallest of the living diprotodont marsupials. The head and body length ranges from 50-65 mm, with the tail length ranging from 60-75 mm. The litte pygmy-possum fur is soft with a pale fawn color on its dorsal side and a grey belly. Both the small size and grey belly of C. lepidus distinguishes it from other members of the family. Cercartetus lepidus teeth have low, rounded cusps associated with their diet of soft foods. However, one of the premolars on each side is usually blade-like or plagiaulacoid (Green, 1983).

Cercartetus lepidus is syndactylous and has an opposable hallux on its hind feet. Other characteristics include a conical head with short muzzle, large eyes, and short, rounded ears (Myers, 1997). No sexual dimorphism is been seen in body size and/or weight (Ward, 1992).

Reproduction

Female C. lepidus have four teats in their pouch, which limits their litter size to four. Females are polyestrous and can probably rear more than one litter per year (Menkhorst, 1995). Little pygmy-possums found in Victoria have been seen to lactate in January, February, April, June, and September, indicating that breeding occurs throughout the year. However, in Tasmania, lactating females have only been seen between September and January; there, breeding is confined to spring and summer (Ward, 1992). Young are weaned at approximately 50 days. Once the young are half grown and too large for the pouch, they are left in the nest while their mom finds food. If the young must be transported, they cling to their mother's back. Cercartetus lepidus reaches maturity at about 3 months (Green, 1983).

Male C. lepidus have been found with regressed testes and testes that are smaller than normal, suggesting that males may not be reproductively active throughout the year (Ward, 1992).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual

Behavior

In captivity, Little Pygmy-possums have been paired, but they are usually solitary in the wild. Because of their small size, pygmy-possums have a difficult time maintaining a high body temperature when it's cold or when there is not enough food available (Green, 1983). To counter this, C. lepidus undergoes alternate periods of activity and dormancy throughout the year. This inactivity is referred to as torpor. These periods of torpor last up to about 6 days, and during them the pygmy-possum's body temperature is about equal to the air temperature. Cercartetus lepidus takes about 20 minutes to regain full activity after being in the torpor state (Collins, 1973). Cercartetus lepidus is a nocturnal animal that stays in its nest under dense cover during daylight. This possum has a 'drifting home range' that is an adaptation to resources that are spatially and temporally unpredictable. It seems that C. lepidus tracks the flowering patterns of major plant species. When food is abundant for C. lepidus, the base of its tail thickens with fat deposits which serve as a short-term energy reserve (Menkhorst, 1995). This adaptation of C. lepidus, along with entering torpor, allows it to live in unpredictable environments (Ward, 1992).

Communication and Perception

Food Habits

Cercartetus lepidus is omnivorous. It feeds on nectar and pollen from a variety of flowering plants. For example, Banksia ornata, Eucalyptus spp., Leptospermum coriaceum, and Astroloma conostephioides pollen have all been found in faecal and gut samples of this mammal. Sugar-water, honey, and apple are also a part of the diet (Ward, 1992). Little pygmy-possums also prey on a wide range of invertebrates including spiders, scorpions, and insect larvae. Small lizards are also included in their diet. The little pygmy-possum secures the prey with its forepaws and tears away portions with its teeth. Daily food consumption is about 7% of its body weight (Collins, 1973).

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • fruit
  • nectar
  • pollen

Conservation Status

Cercartetus lepidus is widespread through northwestern Victoria and also present in a number of conservation reserves. The status of the little pygmy-possum should be secure as long as there are not any major change in land-use on public land or to fire regimes. Cercartetus lepidus can survive fire, but the long-term effects are not yet known (Menkhorst, 1995). Extensive forest clearing has removed much of the habitat of C. lepidus on the mainland, yet sufficient habitat is still left in Tasmania. The woodchip industry might also play a role in the future of the Little Pygmy-possum (Green, 1983).

Other Comments

Fossil remains in eastern New South Wales indicate that the range of C. lepidus was condensing southward before the first Europeans arrived (Burton, 1987). Since then, most of the forest has been cleared, destroying the little pygmy-possum's habitat. Cercartetus lepidus is also referred to as tasmanian pygmy-possum (Green, 1983).

Contributors

Colette Hendricks (author), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

References

Burton, J. 1987. The Collins Guide to the Rare Mammals of the World. The Stephen Green Press, Lexington.

Collins, L. 1973. Monotremes and Marsupials. Smithsonian Institution Press, City of Washington.

Green, R.H. 1983. Little Pygmy-possum. pp.164-165 in: Strahan, R. (ed). The Complete Book of Australian Mammals. Angus and Robertson, Sydney.

Menkhorst, P. 1995. Mammals of Victoria: Distribution, Ecology, and Conservation. Oxford University Press, Melbourne.

Myers, P. 1997. Animal Diversity Web. http://www.oit.itd.umich.edu/projects/ADW

Ward, S. J. 1992. Life History of the Little Pygmy-possum, Cercartetus lepidus in the Big Desert, Victoria. Australian Journal of Zoology, (40) 43-55.