Tasmanian Pygmy Possum
Encyclopedia
The Tasmanian pygmy possum (Cercartetus lepidus), also known as the little pygmy possum, is the world's smallest possum
. It was first described by Oldfield Thomas
in 1888, after he identified that a museum specimen labelled as an eastern pygmy possum
in fact represented a species then unknown to science. The holotype
resides in the British Museum of Natural History.
, and it is the smallest of all the known species of possum
. Adults range from 6.6 to 7.5 cm (2.6 to 3 ) in head-body length, with a 6 to 7.2 cm (2.4 to 2.8 ) tail, and weigh just 7 to 10 g (0.246917734735784 to 0.35273962105112 ). Their fur is soft and thick, and is fawn in colour over most of the body, fading to a pale grey on the underparts.
The snout is short with long whisker
s, and the eyes are directed forwards and surrounded by slightly darker fur, although without the conspicuous black rings seen on other pygmy possum
s. The ears are mobile and largely hairless. The tail is prehensile, and thickly furred at the base, which may be widened by fat stores beneath the skin. The remainder of the tail is relatively narrow and cylindrical, with only sparse hair between numerous tiny scales.
, but was at one time thought to be extinct elsewhere. In 1964, a living animal was discovered on Kangaroo Island
in South Australia
, and further populations have since been discovered in the Murray-Darling basin in South Australia
and Victoria
. There are no formally recognised subspecies, although it has been proposed, based on genetic information, that the mainland and Tasmanian populations may be subspecies, or even entirely separate species. They inhabit sclerophyll
forest, mallee
, and open heathland vegetation.
The oldest fossils for this species date from the late Pleistocene
, and were found on the mainland, with the oldest known Tasmanian fossils being much younger. Fossils have been found as far afield as eastern Victoria and New South Wales
, suggesting that the species was once much more widespread than it is today.
, the latter two primarily coming from Banksia
and eucalypt
s. Their preference for eating pollen without destroying the host flower may mean that they help to pollinate
some species of plant. Known predators include Tasmanian devil
s, quoll
s, kookaburra
, masked owls, and tiger snakes.
During cold weather, especially below about 6 °C (42.8 °F), Tasmanian pygmy possums have the ability to enter torpor
. While in this state, body temperature drops, and oxygen consumption falls to just 1% of normal.
Breeding occurs throughout the year, although it may be more common in spring and summer. The female has a well-developed pouch
containing four teats, which therefore limits the maximum size of a litter to this number. The young leave the pouch at around 42 days, although they may cling to the mother's fur and be carried about after this age. They leave the nest to fend for themselves at around 90 days of age.
Possum
A possum is any of about 70 small to medium-sized arboreal marsupial species native to Australia, New Guinea, and Sulawesi .Possums are quadrupedal diprotodont marsupials with long tails...
. It was first described by Oldfield Thomas
Oldfield Thomas
Oldfield Thomas FRS was a British zoologist.Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and sub-species for the first time. He was appointed to the Museum Secretary's office in 1876, transferring to the Zoological Department in 1878...
in 1888, after he identified that a museum specimen labelled as an eastern pygmy possum
Eastern Pygmy Possum
The Eastern Pygmy Possum is a diprotodont marsupial of south-eastern Australia. Occurring from southern Queensland to eastern South Australia and also Tasmania, it is found in a range of habitats, including rainforest, sclerophyll forest, woodland and heath.This species is very small, weighing...
in fact represented a species then unknown to science. The holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
resides in the British Museum of Natural History.
Description
Although it is a marsupial, the Tasmanian pygmy possum superficially resembles a dormouseDormouse
Dormice are rodents of the family Gliridae. Dormice are mostly found in Europe, although some live in Africa and Asia. They are particularly known for their long periods of hibernation...
, and it is the smallest of all the known species of possum
Possum
A possum is any of about 70 small to medium-sized arboreal marsupial species native to Australia, New Guinea, and Sulawesi .Possums are quadrupedal diprotodont marsupials with long tails...
. Adults range from 6.6 to 7.5 cm (2.6 to 3 ) in head-body length, with a 6 to 7.2 cm (2.4 to 2.8 ) tail, and weigh just 7 to 10 g (0.246917734735784 to 0.35273962105112 ). Their fur is soft and thick, and is fawn in colour over most of the body, fading to a pale grey on the underparts.
The snout is short with long whisker
Whisker
Whisker may refer to:* an element of box plots* cat's whisker diode, a thin wire used as a contact on a crystal radio receiver* facial hair, hair on the face of a human* vibrissa, a hair on the face of a mammal, used for sensing the surroundings...
s, and the eyes are directed forwards and surrounded by slightly darker fur, although without the conspicuous black rings seen on other pygmy possum
Pygmy possum
The pygmy possums are a family of small possums that together form the marsupial family Burramyidae. There are five extant species of pygmy possum, grouped into two genera. Four of the species are endemic to Australia, with one species also co-occurring in Papua New Guinea and Indonesia.Pygmy...
s. The ears are mobile and largely hairless. The tail is prehensile, and thickly furred at the base, which may be widened by fat stores beneath the skin. The remainder of the tail is relatively narrow and cylindrical, with only sparse hair between numerous tiny scales.
Distribution and habitat
The Tasmanian pygmy possum is found throughout TasmaniaTasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
, but was at one time thought to be extinct elsewhere. In 1964, a living animal was discovered on Kangaroo Island
Kangaroo Island
Kangaroo Island is Australia's third-largest island after Tasmania and Melville Island. It is southwest of Adelaide at the entrance of Gulf St Vincent. Its closest point to the mainland is off Cape Jervis, on the tip of the Fleurieu Peninsula in the state of South Australia. The island is long...
in South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
, and further populations have since been discovered in the Murray-Darling basin in South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
and Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
. There are no formally recognised subspecies, although it has been proposed, based on genetic information, that the mainland and Tasmanian populations may be subspecies, or even entirely separate species. They inhabit sclerophyll
Sclerophyll
Sclerophyll is the term for a type of vegetation that has hard leaves and short internodes . The word comes from the Greek sclero and phyllon ....
forest, mallee
Mallee
Mallee may refer to:* Mallee , the habit of woody plants that grow with multiple stems from underground lignotubers* Mallee , a biogeographic region in southern Western Australia...
, and open heathland vegetation.
The oldest fossils for this species date from the late Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, and were found on the mainland, with the oldest known Tasmanian fossils being much younger. Fossils have been found as far afield as eastern Victoria and New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
, suggesting that the species was once much more widespread than it is today.
Behaviour
The Tasmanian pygmy possum is nocturnal and arboreal. It lives primarily in shrubland or forest undergrowth, and, although a good climber, rarely ventures into the higher branches of trees, presumably because this would make it more vulnerable to avian predators. Pygmy possums use strips of bark to construct dome-like nests in tree cavities or rotten wood, but are solitary animals that do not share their nests with other individuals except for their own young.Biology
Tasmanian pygmy possums are omnivorous, feeding on insects, spiders, small lizards, nectar, and pollenPollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
, the latter two primarily coming from Banksia
Banksia
Banksia is a genus of around 170 species in the plant family Proteaceae. These Australian wildflowers and popular garden plants are easily recognised by their characteristic flower spikes and fruiting "cones" and heads. When it comes to size, banksias range from prostrate woody shrubs to trees up...
and eucalypt
Eucalypt
Eucalypts are woody plants belonging to three closely related genera:Eucalyptus, Corymbia and Angophora.In 1995 new evidence, largely genetic, indicated that some prominent Eucalyptus species were actually more closely related to Angophora than to the other eucalypts; they were split off into the...
s. Their preference for eating pollen without destroying the host flower may mean that they help to pollinate
Pollination
Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...
some species of plant. Known predators include Tasmanian devil
Tasmanian Devil
The Tasmanian devil is a carnivorous marsupial of the family Dasyuridae, now found in the wild only on the Australian island state of Tasmania. The size of a small dog, it became the largest carnivorous marsupial in the world following the extinction of the thylacine in 1936...
s, quoll
Quoll
The quoll, or native cat, is a carnivorous marsupial native to mainland Australia, New Guinea and Tasmania. It is primarily nocturnal and spends most of the day in its den. There are six species of quoll; four are found in Australia and two in New Guinea...
s, kookaburra
Kookaburra
Kookaburras are terrestrial kingfishers native to Australia and New Guinea. They are large to very large, with a total length of . The name is a loanword from Wiradjuri guuguubarra, and is onomatopoeic of its call...
, masked owls, and tiger snakes.
During cold weather, especially below about 6 °C (42.8 °F), Tasmanian pygmy possums have the ability to enter torpor
Torpor
Torpor, sometimes called temporary hibernation is a state of decreased physiological activity in an animal, usually characterized by a reduced body temperature and rate of metabolism. Animals that go through torpor include birds and some mammals such as mice and bats...
. While in this state, body temperature drops, and oxygen consumption falls to just 1% of normal.
Breeding occurs throughout the year, although it may be more common in spring and summer. The female has a well-developed pouch
Pouch (marsupial)
The pouch is a distinguishing feature of female marsupials ; the name marsupial is derived from the Latin marsupium, meaning "pouch". Marsupials give birth to a live but relatively undeveloped fetus called a joey. When the joey is born it crawls from inside the mother to the pouch...
containing four teats, which therefore limits the maximum size of a litter to this number. The young leave the pouch at around 42 days, although they may cling to the mother's fur and be carried about after this age. They leave the nest to fend for themselves at around 90 days of age.