There is little ecological literature on western pygmy possums since their nocturnal and arboreal lifestyle makes data acquisition difficult. Lack of detailed knowledge may be one of the most important factors threatening the conservation efforts of this species.
Like other pygmy possums, western pygmy possums have keen senses of vision, hearing, taste, and touch. They probably use chemical cues to communicate reproductive state.
Communication Channels: visual ; tactile ; acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Western pygmy possums are listed as endangered under Schedule 1 of the New South Wales Threatened Species Conservation Act 1995. However, they are listed as common but limited throughout the rest of their range in southern Australia.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse effects of western pygmy possums on humans.
Western pygmy possums are important members of the native ecosystems in which they live.
Western pygmy possums serve as prey for small to medium-sized nocturnal predators in Australia. They may also serve a role in pollinating plants through their nectarivory.
Ecosystem Impact: pollinates
Based on their general biology and morphology it was initially thought that western pygmy possums were primarily insectivorous. A study done by Horner in 1994 found an abundance of Banksia pollen in the feces of western pygmy possums, with no invertebrate remains present. However, soft-bodied invertebrates, like pupae and larvae, are usually assumed to be totally digestible and would not be found in any scat samples. These possums are currently considered nectarivorous, but may also be insectivorous. They have also been found to prey on small lizards (Smith 1995).
Animal Foods: reptiles; insects
Plant Foods: nectar
Primary Diet: carnivore (Insectivore ); herbivore (Nectarivore )
Western pygmy possums are found only on the Australian continent, more specifically in the southwestern, southern, and southeastern portions of Australia. Cercartetus concinnus has been found in only 50 locations within the New South Wales, South Australia, Victoria, and Western Australia areas of the continent.
Biogeographic Regions: australian (Native )
Western pygmy possums are terrestrial mammals that reside in temperate forests in Australia. These pygmy possums are arboreal and tend to nest during the day in a tree hollow filled with leaves, but can also nest on the ground in clumps of twigs. They prefer habitats with a dense shrubby understory that provides shelter and food. They are most abundant in the woodlands of southwest Western Australia, and can also be found in some bushlands. While small remnants of bushland can provide suitable habitat, they may not be large enough to support viable populations of western pygmy possums in the long term. Structurally diverse habitats are necessary for nesting and traveling. Western pygmy possums prefer to travel using clumps of twigs or leaf litter as cover, indicating that diverse ground cover should be a focus of conservation efforts.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest
No information was found on longevity in western pygmy possums.
Western pygmy possums are small, nocturnal marsupials. Adults average 80 mm in body length, with an 86 mm long tail to aid them when moving through foliage. The average weight of an adult is only 13 grams. They are fawn or reddish-brown on the dorsal side, and are white ventrally with a finely-scaled naked tail. These pygmy possums have a noticeably whiskered and short, pointed snout, very large eyes which are well adapted for seeing at night, and thin rounded ears. For comparison, western pygmy possums are no larger than a typical kiwi fruit.
Average mass: 13 g.
Average length: 80 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
Western pygmy possums are small and are likely to fall prey to a number of small to medium sized nocturnal predators, such as introduced, domestic cats and snakes. Their nocturnality and arboreality is likely to protect them from some predation.
Known Predators:
Little information on mating systems in western pygmy possums is available in the literature.
Western pygmy possums can breed year-round when conditions are favorable. However, females can employ delayed implantation if it is necessary to delay reproduction until environmental conditions are more suitable for reproduction (Pestell 2005). Females typically enter torpor to escape poor environmental conditions, such as low temperatures or decreased food resources, and implantation of the embryo occurs when conditions are again favorable.
Female western pygmy possums differ from other members of the Burramyidae family in that they have six teats in their forward-facing pouch, rather than four (Pestell 2005). Breeding can occur anytime throughout the year. A typical female may give birth to 2 or 3 litters of up to 6 young in a year. The young typically remain in the pouch for their first 25 days, after which they are transferred to a nest.
Breeding interval: Females can breed 2 to 3 times a year.
Breeding season: Western pygmy possums can breed throughout the year if conditions are favorable.
Range number of offspring: 1 to 6.
Average time to independence: 25 days.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous ; delayed implantation
Female western pygmy possums care for and protect their young until they reach independence, but little is known about the details of parental investment and development in these possums.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
The western pygmy possum (Cercartetus concinnus), also known as the southwestern pygmy possum or the mundarda, is a small marsupial found in Australia. Genetic studies indicate its closest relative is probably the eastern pygmy possum,[4] from which its ancestors diverged around eight million years ago.[5]
John Gould provided the first description of Cercartetus concinnus, which was read before the Zoological Society of London and published in 1845. Gould assigned the new species to the genus Dromicia, recognising an affinity with a previously described species found in Tasmania.[3] The animal was also described in the same year as Phalangista (Dromicia) neillii by G. R. Waterhouse, recognised as a synonym of the species.[6]
The western pygmy possum is unusual in Cercartetus, as, unlike its grey relatives, the fur over most of its body is a bright cinnamon colour. It has pure white underparts, which also distinguishes it from its relatives, and has a thin ring of dark brown fur in front of the eyes. It possesses long and rounded flesh-coloured ears, large and black protruding eyes. The muzzle is only sparsely covered in hair, showing the pink colour at the bare parts.[7] The species has long whiskers. The prehensile tail is long and covered with fine scales, rather than fur, and not enlarged at the base. The hind feet have opposable first digits, while all four feet have broad pads at the tips of the toes.[8]
Although small compared with most other possums, it is one of the larger pygmy possums, with adults ranging from 70–100 millimetres in head-body length with a tail 70–90 mm long. Adult weight ranges from 8 to 18 grams. The female has a well-developed pouch, opening to the front, containing six teats.[7] At up to 12 mm in length, the tongue is unusually large for such a small animal.[8]
This possum is vulnerable due to habitat loss and lack of food. The distribution range includes Southwest Australia, on the south coast and the wheatbelt, and areas of South Australia, Kangaroo Island, and Victoria south to Edenhope.[7] It is also found in far southwestern New South Wales, where it is listed as endangered.[9] It inhabits semi-arid woodland, shrubland, and heath, dominated by plants such as Callistemon (bottlebrushes), melaleuca, banksia, and grevillea.[8] Although there had been previously thought to be two subspecies, separated in distribution by the Nullarbor Plain, genetic studies have not revealed any significant difference between the eastern and western populations.[5] Furthermore, while the species is no longer native to the area, fossils from the Nullarbor Plain region are known.[8]
The western pygmy possum is solitary and nocturnal.[10] During the day, they shelter in tree hollows or other natural crevices, birds' nests, or dense vegetation. At night, they travel in search of food or mates, typically moving around 50 m (160 ft) each day, and they may migrate to different areas over the course of a year, depending on local plant resources. They spend most of their time in the trees, using their grasping paws and prehensile tails to grip onto branches, grasp nest materials, and open flowers to access nectar. They have been described as making a rapid chattering noise.[8]
It feeds primarily on nectar and pollen, especially from plants such as melaleuca and eucalyptus, and may play a role in the pollination.[11] It also supplements its diet with insects.[7] Native predators include quolls, snakes, and owls, although in modern times, the animal also falls prey to introduced carnivores such as red foxes and domestic cats.[8]
Western pygmy possums have the ability to enter torpor during inclement or cold weather, enabling them to conserve energy and food reserves. During bouts of torpor, which may last for up to seven days at a time, body temperature falls to within one degree Celsius of ambient, and oxygen consumption to just 1% of normal. They sleep on their fronts, with their ears folded over their eyes, and their long tails coiled beneath their bodies. Compared with other mammals of similar size, they rouse from torpor unusually quickly.[12]
Western pygmy possums can breed throughout the year, although they do so more commonly in the spring, and give birth to litters of four to six young. The mother often carries more than six embryos at a time in her womb, but because she has only six teats, and marsupial young remain attached to an individual teat for much of their early lives, six is the maximum number she is able to rear.[13] Unusually, however, the mother may give birth just two days after weaning a previous litter, with her teats dramatically changing in size to accommodate the smaller young, and the mammary glands reverting to production of colostrum.[8]
The young are still blind when they leave the pouch at around 25 days of age; they initially remain within the nest, and are fully weaned at around 50 days. Females reach sexual maturity at 12 to 15 months old.[8]
The species is currently classified as Least Concern by the IUCN. However, several Australian states (New South Wales and South Australia) and individual parks and conservation regions have nationally listed it as Vulnerable, Endangered or Critically Endangered due to the pressure from vegetation clearing, the reduction of food sources (overgrazing of livestock), fire regimes, and introduced predators such as the red fox and feral cats.[8][14]
The western pygmy possum (Cercartetus concinnus), also known as the southwestern pygmy possum or the mundarda, is a small marsupial found in Australia. Genetic studies indicate its closest relative is probably the eastern pygmy possum, from which its ancestors diverged around eight million years ago.