Fairy possum
Leadbeater's possum (Gymnobelideus leadbeateri ) is a critically endangered possum largely restricted to small pockets of alpine ash, mountain ash, and snow gum forests in the Central Highlands of Victoria, Australia, north-east of Melbourne. It is primitive, relict, and non-gliding, and, as the only species in the petaurid genus Gymnobelideus, represents an ancestral form. Formerly, Leadbeater's possums were moderately common within the very small areas they inhabited; their requirement for year-round food supplies and tree-holes to take refuge in during the day restricts them to mixed-age wet sclerophyll forest with a dense mid-story of Acacia. The species was named in 1867 after John Leadbeater, the then taxidermist at the Museum Victoria. They also go by the common name of fairy possum. On 2 March 1971, the State of Victoria made the Leadbeater's possum its faunal emblem.
These small, tree-dwelling marsupials are native and endemic exclusively to a very small area in Victoria (Australia). For about half a century, Leadbeater's possums were believed to be extinct, but in the beginning of 1960s the species was rediscovered.
The species is found exclusively in Australia, where its range is restricted to 2 small areas, one of which is near the western end of Victoria’s Central Highland, and the other one near Yellingbo, east of Melbourne (Victoria). These animals can be found in forests, dominated by mountain swamp gum (Eucalyptus camphora), silver wattle (Acacia dealbata), shining gum (Eucalyptus nitens) and Victorian ash trees (Eucalyptus regnans). Leadbeater’s possums generally prefer damp, mountainous forests with abundance of thick plants and openings in trees.
These possums are nocturnal and sedentary animals. Leadbeater’s possums are known to form groups of 4 - 8 individuals, usually consisting of an adult pair and their young. Members of a group share the same nest and identify each other by smells. Grooming and spread of odors are common activities, enhancing social bonds between members of a group. Each group occupies an area of 2.5 - 7.5 acres, fiercely defending its territory. These animals have a female-dominated social hierarchy with each group, having only one adult female. Meanwhile, other adult females, sharing the same nest, typically form an unstable group, members of which often engage in fight. Females usually leave their group earlier than males. They are also known for their violence and aggressive behavior towards each other and occasionally, their own daughters.
These animals are carnivores (insectivores), they feed upon a wide variety of arthropods such as crickets, beetles and spiders, which are found under the shedding bark of eucalypts. Leadbeater’s possums are also known to favor gum, sap and nectar of eucalypts. In addition, they consume honeydew - a sweet substance, which is made by lerps.
Leadbeater’s possums are monogamous, which means that one male mates with one female exclusively. These animals have two breeding seasons: one lasts from April to June, and the other - from October to December. Gestation period lasts for up to 20 days, yielding a single or two young per litter. Newborn babies climb into the pouch of their mother, where they remain for 85 days, feeding upon maternal milk. By the end of this period, young possums are developed enough to come out of the pouch and begin to forage. Males are weaned by 15 months old, while females - earlier - by the age of 10 months. Since young females are usually not welcome on territories of adult females, unfortunately, many of them to do not survive. As a result, by the age of 2 years, when Leadbeater’s possums are sexually mature, males outnumber females three to one.
The primary threats to this endangered species are wildfire and logging, which are, in fact, interrelated: timber harvesting of the ash-type forests clears the area from large trees, causing wildfires and reseeding, which leads to destruction of natural habitat of these animals. Fires also destroy nesting sites of Leadbeater’s possums, which are located in hollows of trees. These hollows take quite a long time to form; the largest Eucalypt tree, for example, takes 150 years to develop favorable nesting sites. Thus, only one conclusion can be drawn from the consideration of the above mentioned facts: constant destruction of a few remaining nesting sites combined with long regeneration is likely to result in complete extinction of Leadbeater’s possums, which can happen in the near future.
The total number of this species' population is currently decreasing. According to IUCN Red List, there are approximately 2,000 mature Leadbeater’s possums today, 200 of which are found at Yellingbo. As a result, Leadbeater’s possum is classified as Critically Endangered (CR) species on the IUCN Red List.
Constructing their nests in dead and decaying trees with abundant populations of insects, Leadbeater's possums feed upon these insects, controlling numbers of their populations and helping balance the ecosystem.
