Possums are one of the most commonly encountered native animals across Australia, particularly in urban and suburban areas. These nocturnal marsupials are an integral part of the Australian ecosystem, with a significant presence from the dense forests to the inner city parks. The possum is a diverse group, with around 30 different species found across the country, ranging from tiny Pygmy Possums to the much larger Brushtail Possums. The existence of these animals is often a source of confusion for international visitors due to a naming mix-up that occurred centuries ago.
Possums vs. Opossums: A Matter of Taxonomy
The primary confusion surrounding the Australian possum stems from the existence of the North American opossum, despite the two being separated by millions of years of evolution. Both animals are marsupials, meaning the females possess a pouch where their young, called joeys, complete their development after a brief gestation period. However, they belong to entirely different taxonomic orders. Australian possums are classified within the order Diprotodontia and the suborder Phalangeriformes, which makes them more closely related to Australian icons like kangaroos, koalas, and wombats. Conversely, the North American opossums are the only marsupials native to the Americas, belonging to the order Didelphimorphia. The similar common name is a result of early European explorers noting a superficial resemblance between the American animal they first encountered and the Australian species they later discovered.
The physical differences between the two groups are noticeable upon closer inspection. Australian possums generally have softer, fluffier fur, a more rounded facial structure, and a tail that is often furry and bushy, particularly in the Common Brushtail Possum. North American opossums, such as the Virginia opossum, tend to have a more pointed snout, coarse fur, and a distinctive, mostly hairless, rat-like tail. This evolutionary divergence highlights a deep separation in their family trees.
The Major Australian Species
The two most frequently observed Australian possums are the Common Brushtail Possum (Trichosurus vulpecula) and the Common Ringtail Possum (Pseudocheirus peregrinus). These two species share much of the same geographical range across eastern and southern Australia, but their physical features allow for easy identification. The Common Brushtail Possum is the larger of the two, comparable to a small domestic cat, and can weigh up to 4.5 kilograms, featuring large, pointed ears and silver-gray to black or copper-colored fur.
The Common Brushtail Possum is defined by its prehensile tail, which is bushy for most of its length, ending in a distinct black, brush-like tip. The Common Ringtail Possum, in contrast, is smaller and more slender, typically weighing less than a kilogram. It has a rounded head, smaller ears, and a much more subtle appearance than its brushtailed counterpart. The Ringtail Possum’s most distinguishing feature is its long, highly prehensile tail, which it uses like a fifth limb for climbing. The tail has a characteristic white tip that covers the last quarter of its length. The Ringtail Possum also builds a spherical nest, called a drey, out of bark and leaves in tree canopies, while the Brushtail Possum often seeks shelter in tree hollows.
Life in the Australian Canopy
Australian possums are predominantly arboreal and strictly nocturnal, spending their days sleeping in sheltered locations and becoming active only after dusk. Their large eyes are adapted for low light, allowing them to navigate the branches of the Australian canopy and suburban environments. The diet of possums is largely herbivorous, focusing on the leaves, flowers, and fruits of native plants, with some species, like the Common Brushtail Possum, occasionally supplementing their diet with insects or bird eggs.
Habitat loss due to urbanization has forced many possums to adapt to life in close proximity to humans. In the absence of natural tree hollows, Brushtail Possums often seek shelter in the eaves, roof cavities, and chimneys of residential homes, while Ringtail Possums will build their dreys in dense garden shrubs. Their adaptability means they can find food in suburban gardens, where they may eat young shoots and flowers, but they also perform an ecological role as pollinators of native flora. Despite sometimes being considered a nuisance in urban settings, all native Australian possums are protected wildlife, and measures must be taken to ensure their welfare when they take up residence in human dwellings.