Possum

Quick Take

• "Possum" and "opossum" aren't interchangeable, and mixing them up means you're describing a completely different animal. See the classification →
• Some possums can fly, and the reason why mirrors an animal that isn't even a marsupial. Discover gliding species →
• A possum joey's lips physically fuse to its mother in a way that sounds impossible, but the reason behind it makes it entirely understandable. See joey development →
• A quarter of Australia's possum species face extinction, yet one species has thrived by moving in with humans. Check conservation status →

Possums are nocturnal animals that can agilely navigate tall trees. Sometimes they venture into human areas and can be heard at night on a roof. The words possums and opossums are often used interchangeably, but they actually mean different things. Opossum refers specifically to the American opossums. Possum, on the other hand, refers to the Australian variety with the scientific name Phalangeriformes. They belong to different orders but are both examples of marsupials.

3 Amazing Possum Facts

• Marsupials are an ancient lineage of mammals that split off from placental mammals approximately 130 to 180 million years ago. Modern possums, kangaroos, and koalas probably evolved from a common ancestor that lived some 20 to 30 million years ago.
• Male and female possums: Males are known as jacks and females as jills, respectively, while a group is called a passel.
• In Australia and some of the nearby islands, the spread of towns and cities has made encounters much more common. Sometimes considered to be a pest, possums like to hide in dark areas such as attics, sheds, and garages, causing damage and destruction to gardens, farms, forests, and equipment. They pose almost no danger to humans unprovoked, but they can spread diseases by piercing the skin with their sharp claws. If you encounter some in or near your residence, then it is a good idea to avoid contact and let professionals remove them in a humane manner.

Classification and Scientific Name

Possums belong to the suborder Phalangeriformes, and their common name derives from the Powhatan word aposoum, meaning “white animal”. Possums are divided into several different families and genera. The family Phalangeridae contains the majority of possums, including the well-known common brush-tail possums (Trichosurus vulpecula) and the cuscus. There are about 70 different species of possums spread throughout the Pacific region. They belong to the marsupial order of Diprotodontia along with kangaroos, wallabies, koalas, and wombats.

The names of some of the possum species include: Common Brushtail, Common Ringtail, Pygmy (with 5 subspecies), Honey, Mountain Brushtail, Northern Brushtail, Green Ringtail, Leadbeater’s, Scaly-tailed, Striped, Lemuroid Ringtail, Coppery Brushtail, Cinereus Ringtail, Rock Ringtail, Western Ringtail, Short-eared Brushtail, Daintree River Ringtail, and Herbert River Ringtail.

Perhaps the most remarkable adaptation among possums is seen in the gliders. As the name suggests, these species have evolved large skin flaps between their limbs that enable them to glide through the air. One species has been observed to travel as much as 65 feet at once. There are a number of different types of gliders as well: squirrel glider, sugar glider, Yellow-bellied glider, mahogany glider, greater glider, and feathertail glider.

The glider possum’s flaps are very similar to the flying squirrel’s (which is actually a rodent and a placental mammal, not a marsupial). This is an example of convergent evolution: two separate animals evolving similar traits for the same reasons. Most of the gliders occupy the genus Petaurus, but the feather-tail glider, which has serrated toe pads for climbing smooth bark, occupies its own genus, appropriately named Acrobates.

Appearance

These traits are generally shared among all possums, but there is still a huge amount of variation, particularly with regard to their size.

The smallest species is the Tasmanian pygmy possum, which measures less than three inches long and weighs less than a pencil. It resembles a mouse more than its cousins, especially with its soft, full fur and mostly hairless ears.

The largest species of possum are the two bear cuscuses (Talaud and Sulawesi), which weigh up to 22 pounds, or about the size of a beagle or spaniel. They also have a prehensile tail that is hairless. These possums have shorter facial features, including their fur and ears. Their fur tends to have a darker coloration of black, gray, and even brown. The bear cuscus’s underside does get a little lighter in color.

Possums vary in other physical characteristics as well. The brush-tail possum has a very furry tail with a naked underside. It is able to use this prehensile tail to grasp tree and bush branches. It also has pointy ears. Notably, both sexes of the common brush-tail have scent glands in their chest that actually stain the fur a reddish color.

The ringtail possum (Pseudocheirus peregrinus), on the other hand, has a multi-colored tail. Uniquely, the last quarter of the tail is tipped with white fur. It almost looks as if someone had dipped the tail in white paint.

Behavior

Possums are animals that vary as much in their behavior as they do in their physical characteristics. The brush-tail possums are nocturnal and solitary creatures that come together only for the breeding season. As the most terrestrial and earthbound of all possums, they can live near human homes and gardens. The ring-tail possums, on the other hand, are highly social creatures that inhabit communal nests known as dreys. These groups usually consist of the male and female breeding pair and the offspring.

Possums are fairly docile, omnivorous animals that only act aggressively when threatened. Some of their defensive behaviors include playing dead, growling, baring their teeth, or secreting a bad odor. When they aren’t hunting, possums spend most of the time grooming or sleeping. Possums communicate with each other (and with potential threats) through both sound and smell. Their suite of alarm calls, mating calls, and location calls includes screeches, hisses, clicks, grunts, and howls. They also have scent glands on their chest to mark territory.

Habitat

The possum is native to the forests of Australia and the surrounding islands of Tasmania, New Guinea, Celebes, and the Solomons. Their most common habitats include rainforests, eucalyptus forests, woodlands, coastal shrublands, and even human neighborhoods. They require only a relatively dense network of trees for shelter, protection, and food.

Diet

Possums have evolved to favor an omnivorous diet that includes insects, eggs, and a variety of plant matter, some of which is poisonous to other animals. If given the opportunity, they will also scavenge on food left over by other animals and people. The exact dietary composition varies based on the availability of food from one location to another, so they can best be described as opportunistic. Some possum species have an enlarged cecum (a pouch in the intestines) to ferment and digest the highly fiber-based foods of their diet. The molar teeth have sharp tips to help them chew through the hard plant matter.

In addition to other food sources, possums eat chickens and other small animals.

Predators and Threats

Possums are commonly preyed upon by snakes, cats, dogs, foxes, owls, tiger quolls, and other large predators. Tiger quolls and snakes are endemic to Australia, but many other species were introduced by European settlers and have driven numbers down. Possums have been hunted by humans for their fur, but the biggest threat to their existence is the destruction of habitat from both fires and human activity. As demonstrated by the 2019–2020 bushfires, such incidents are greatly exacerbated by climate change.

Reproduction, Babies, and Lifespan

Reproduction varies from monogamy (a single mate) to polygamy (multiple mates) and almost everything in between. Only the mountain brushtail possum has the ability to change its mating system on a whim based on how much food is available in the environment. Males court females with their loud calls and may sire several groups of young throughout the entire mating season.

Once the pair copulates, the female produces one or two (rarely three) viable offspring, typically around the middle months of the year. Some species produce up to 10 offspring, but most of the babies quickly die off, leaving only a few behind. To maximize the chances of survival, the mother finds a comfortable hiding place in tree hollows or abandoned bird nests to shelter her young. Only a few species actually construct nests from scratch.

As with many other types of animals, the mother is responsible for the majority of parenting duties, while fathers contribute almost nothing to their offspring’s survival. The common ring-tail possum is the only species in which the male also takes a prominent role in caring for the young.

The gestation period is usually quite short. Among the brush-tail possums, it lasts only for 16 or 17 days. The young joeys, as they’re called, crawl from the birth canal into the mother’s pouch for the purpose of feeding on her milk. At this stage, they are still blind and deaf and only measure a few centimeters long. The joeys are so dependent on the mother that their lips fuse around the nipple, maintaining constant contact for the first several weeks of life. Even as it becomes more independent, the joey will stay within the mother’s pouch for protection and security during the next few months. Once it finally becomes too big for the pouch, it will sometimes migrate to the mother’s back.

The possum usually reaches sexual maturity within the first year or two of life. Many fall victim to predators and diseases before they can die of natural causes, so the lifespan of some species is usually no more than 10 or 15 years in the wild. They can live even longer in captivity where they are safe from most threats.

Population

Population numbers are difficult to estimate, but conservation status varies quite drastically by species. According to the IUCN Red List, an international organization that tracks the conservation status of species worldwide, possums can range between least concern and critically endangered. The brush-tailed possum, which is widespread throughout the coastal regions of Australia, has integrated so well into human society that it is a common sight. On the other end of the spectrum, the western ring-tail possum and the fairy possum are both critically endangered.

Many species are currently afforded protection by the government of Australia. It is illegal to hunt, trap, or kill many of the possums for any reason. Nevertheless, it is estimated that a quarter of Australia’s 27 possum species are currently threatened with extinction.

In the Zoo

The San Diego Zoo, which is one of the few zoos in the United States that has Australian possums of any kind, has a long history with the eastern common ring-tail possums. The original three members (a male and two females) were brought to the zoo back in 1984. After several years without any possums, the zoo received more from the Healesville Sanctuary in Victoria, Australia, but they are not always on exhibit.