Common brushtail possum

Common Brushtail Possum
Conservation status
Least Concern
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Infraclass:	Marsupialia
Order:	Diprotodontia
Family:	Phalangeridae
Genus:	Trichosurus
Species:	T. vulpecula
Binomial name
Trichosurus vulpecula (Kerr, 1792)

The Common Brushtail Possum (Trichosurus vulpecula, from the Greek for "furry tailed" and the Latin for "little fox") is the largest possum, and the Australian marsupial most often seen by city-dwellers, since it is one the very few that thrives in cities as well as a wide range of natural and human-modified environments. Despite its resemblance to a fox's brush, the characteristic tail is prehensile and is naked on its lower underside.

Like most possums, the Common Brushtail is nocturnal. It is mainly a folivore, but supplements its usual diet of leaves with fruit, invertebrates, flowers, buds, and whatever else is available. In most Australian habitats, leaves of Eucalyptus are a significant part of the diet but rarely the sole item eaten. This is probably because of the tannins and other chemical defences present in eucalypt leaves. Around human habitations, Common Brushtails are inventive and determined foragers with a liking for fruit trees, vegetable gardens, and kitchen raids.

Brushtail Possum in Brisbane, Queensland, Australia

Brushtail Possum in Sydney, New South Wales, Australia

They are highly inquisitive and live in troupes of about a dozen individuals with a complex social structure not dissimilar from wolves and primates.

During the day, Common Brushtails sleep in a den in a hollow tree or any other convenient place, notably ceiling spaces that are not securely sealed. Although primarily arboreal and not found in places without trees to provide refuge, they spend a good deal of time on the ground. They are able to stand upright.

The very loud hissing, crackling territorial call of the male Common Brushtail has a harsh quality. They have a number of other vocalizations, mainly consisting of pitched clicks. Most are also relatively quiet. Socially they may be solitary or they may form small groups which share territory.

Keeping of Brushtail Possums is prohibited in many areas, and they do not make good pets. If hand reared they will become tame to humans, but still keep an instinctive urge to explore their surrounding area which can bring them into contact with a number of threats. Not the least of which is the wild possums in the area which will be highly territorial and aggressive to any new possum. Feeding of hand reared possums is also involved, after weaning from a replacement possum milk formula they need a good mixture of native leaves and flowers, as well as fruits and vegetables. A common mistake is to feed captive possums solely on fruit and vegetables, which inhibits the correct development of gut microbes required for digestion, and can cause death.

New Zealand

European settlers aiming to establish a fur industry introduced the Common Brushtail to New Zealand, where there are now about 70 million Common Brushtail Possums. Their introduction has been ecologically damaging because the native vegetation has evolved in the absence of mammalian herbivores. Possums selectively browse native vegetation causing particular damage to broadleaved trees, notably Metrosideros species including rata. This leads to competition for food with native forest birds, changes in forest composition and eventually canopy collapse. Possums are opportunists and will predate the eggs of nesting native birds. They do not have so much impact on Southern Beech (Nothofagus), but their presence tends to reduce the species diversity of Nothofagus forest since they eat many of the other species that would naturally be present. The predation of bird eggs and chicks and has led them to be referred to as "reluctant folivores" in that they eat foliage to survive but prefer other foods.[1]

Possums are also said to be vectors of bovine tuberculosis, which provides a major threat to the dairy, beef and deer farming industries.[2] The transmission path has yet to be discovered.

Attempts to reduce numbers by trapping and poisoning have had some success. Trapping and cyanide are generally used by individual hunters as pest control or fur harvesting, while the Department of Conservation (DoC) uses sodium monofluoroacetate (1080)[3] to target larger areas. Studies by DoC have found that the risk of the few losses of native birds; (34 individuals in 70 aerial drop operations) and native invertebrates and mammals are outweighed by the recovery of the native species once the competition for food and predation has been eased. There is the added benefit of a by-catch of other invasive species. There have been isolated reports of pets, in particular dogs, succumbing to poisoning from 1080, probably through eating possum carcasses. The New Zealand Animal Health Board (AHB)[4] and DoC jointly operate poison drops. The effects of these drops upon the environment are considered by ERMA [5] and in consultation with Maori.[6]. There is significant argument against the use of 1080. [7]

To prevent damage to young trees it seems to be necessary to keep numbers very low, perhaps 5% of the levels that would be reached without interference. The possum is widely regarded in New Zealand as a major ecological threat, and some forestry industry funded ecological organisations such as the Ecologic Foundation encourage its elimination; however its impacts are compounded by those of other introduced species such as Red Deer and Goats, not to mention human activities such as agriculture, forestry, and mining. DoC is the largest single agency involved in possum control and much possum control is also carried by the AHB, councils and regional authorities, especially to combat the threat of bovine tuberculosis.

A small fur industry was developed, and possum trapping and shooting continues to the present day, and the fur is often sold as 'eco-fur' by a number of small manufacturing and retailing businesses[8]. The numbers of animals taken for fur is insignificant in relation to the numbers killed in poisoning. Environmentalists question whether the industry is compatible with the aim of drastically reducing or eliminating possums. A number of New Zealand companies[9]are exporting possum carcasses to Taiwan, Hong Kong and Malaysia for human consumption, where possum is known as the delicacy kiwi bear. There is also a small industry processing possum meat as 'Possyum' dog food[10], also for export. In a bizarre example of "coals to Newcastle", NZ Biosecurity [11] have passed regulations governing the import of frozen possum meat from Australia for human consumption. dseefffgsfghgdfg

United States

The Common Brushtail Possum has also been introduced to North America and possibly the Eurasian continent. Environmental effects have so far been relatively minor perhaps due to the presence of predators that prevent population densities from becoming excessive.

Gallery

• 
  Common Brushtail Possum
• 
  Common Brushtail Possum eating leaves of a fruit tree
• 
• 
  Common Brushtail Possum - Grampians National Park, Victoria, Australia

References

• Template:IUCN2006
• Cowan, P. E., et al. (1997). Effects of possum browsing on northern rata, Orongorongo valley, Wellington, New Zealand. Journal of the Royal Society of New Zealand, 27, 173-179.
• Marsh, K. J., Wallis, I. R., & Foley, W. J. (2003). The effect of inactivating tannins on the intake of Eucalyptus foliage by a specialist Eucalyptus folivore (Pseudocheirus peregrinus) and a generalist herbivore (Trichosurus vulpecula). Australian Journal of Zoology, 51, 41-42.
• Payton, I. J., et al. (1997). Response of selected tree species to culling of introduced Australian brushtail possums Trichosurus vulpecula at Waipoua Forest, Northland, New Zealand. Biological Conservation, 81, 247-255.
• Rogers, G. M., & Leathwick, J. R. (1997). Factors predisposing forests to canopy collapse in the southern Ruahine Range, New Zealand. Biological Conservation, 80, 325-338
• Groves, C. P. (2005). Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. p. 50. ISBN 0-801-88221-4. OCLC 62265494.

External links

• Brushtail Possum
• Landcare Research NZ
• Brushtail Possum at Animal Diversity Web