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 60 million Common Brushtail Possums. Their introduction has been ecologically damaging because the native vegetation has evolved in the absence of mammalian
herbivores. The possums do particular damage to broadleaved trees, notably ''
Metrosideros'' species including ''
rata'', leading to canopy collapse and potentially competing for food with native forest 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. They are said to prey on bird eggs and chicks by New Zealand farm forestry interests. Possums are also said to be vectors of
bovine tuberculosis which provides a major threat for cattle and farmed deer although the transmission path has not been discovered nor proven to even exist. Attempts to reduce numbers by trapping and poisoning have had only short-term success, and the poisons used, usually
sodium monofluoroacetate (1080) or
cyanide are environmental hazards in themselves resulting in many consumers avoiding food exports from New Zealand due to such contamination.
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. The
New Zealand Department of Conservation is the largest single agency involved in possum control and much possum control is also carried by councils and regional authorities 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'. The numbers of animals take for fur is significant in relation to the numbers killed in poisoning. Environmentalists question whether the industry is compatible with the aim of drastically reducing or eliminating possums. Auckland company Arex International is exporting possum carcasses to Taiwan, Hong Kong and Malaysia for human consumption, where possum is known as the delicacy kiwi bear.
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
References
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★ 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
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External links
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Brushtail Possum
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Landcare Research NZ