RINGTAIL AND GREATER GLIDING POSSUMS: Pseudocheiridae

PHYSICAL CHARACTERISTICS

Ringtail and greater gliding possums are marsupial mammals. They range in length from 13 to 37 inches (32 to 95 centimeters) and weigh between 4 ounces and 79 pounds (115 grams to 22.5 kilograms). In this family there are two distinct types of possums. The greater gliding possums have a membrane, or thin layer of skin, between their front legs and their back legs. They spread their arms and legs when they leap from tree to tree and the membrane acts like a parasail or parachute and allows them to glide. The other group, known as the ringtail possums, is much different. They do not have this membrane, and their legs are short and stocky. The greater gliding possums can be up to 37 inches (95 centimeters) long, including their long tail, and weigh up to 42 ounces (1,200 grams).

Ringtail possums are furry and can be light gray, cream, orange, or dark brown in color. One species, the green ringtail, even looks green because of a combination of yellow, black and white fur. Ringtail possums have short round ears and a tail that is bare near the end.

Because they are marsupial mammals, ringtail and greater gliding possums are different from most familiar mammals such as cats, horses and humans. These familiar mammals are all eutherian (yoo-THEER-ee-an) mammals, which means they have a well-developed placenta. A placenta is an organ that grows in the mother's uterus, womb, and lets the mother and developing baby share food and oxygen. Marsupial mammals do not have this type of placenta. Because of this, they give birth to young that are not physically developed enough to be able to survive on their own. Instead, the young are carried around either in a pouch or attached to the mother's teats, or nipples, on her underbelly until they have completed their development.

GEOGRAPHIC RANGE

Ringtail and greater gliding possums live along the eastern coast of Australia from its northern-most tip near New Guinea to its southern-most tip near Tasmania. They can also be found in the more mountainous areas of New Guinea, as well as Tasmania, and the southwestern tip of Australia.

HABITAT

Most of the species that live in New Guinea, live in mountain forests. In Australia there are a number of different species that occupy a variety of different habitats. One species known as the rock possum lives on the rocky ground. Most other ringtails are arboreal, meaning they live in trees. Some of these tree-dwelling possums live in Australia's rainforests while others live in more dry and less dense forests.

DIET

Ringtail and greater gliding possums are herbivores, which means that they eat plants. Most of their diet is made up of leaves, especially eucalyptus (yoo-kah-LIP-tus) leaves. Some species also eat fruits and flowers. These animals have teeth that are specially suited to grinding up leaves. They also all have a large cecum (SEE-kum), which is a pouch in the digestive system. In order to get enough nutritional value from the leaves they eat—eucalyptus leaves, especially, have low nutritional value—the leaves must be broken down. In the cecum, these animals have special bacteria that break down the leaves, so that they can be used by the animal.

BEHAVIOR AND REPRODUCTION

Ringtail and greater gliding possums are nocturnal, which means that they are active at night and sleep during the day. Almost all species live in trees. Social organization and interaction are important to most species in this family. Some live in bonded pairs and raise their young together. Most of the rainforest species live alone, but some of the other species spend time in groups and share sleeping spots. These possums use vocal calls to communicate with each other and with their young. None of them are territorial or protect a particular area.

Ringtail and greater gliding possums give birth to one or two young once a year. The young are born underdeveloped and crawl into their mother's pouch to continue to grow and mature. After 90 to 120 days in the mother's pouch, they leave and are carried on her back for another three months. After ten months the young become independent.

RINGTAIL AND GREATER GLIDING POSSUMS AND PEOPLE

Most ringtail and greater gliding possums do not have a significant impact on people, except for the scientists who study them. In New Guinea, some larger species are hunted for food. Some species living near people's homes have been known to eat flowers from gardens.

DIGESTIVE RECYCLING

Greater gliding and ringtail possums eat plants like eucalyptus leaves that are tough, difficult to digest, and do not contain a lot of nutrients or calories. To get enough energy out of these leaves, they pass them through their digestive system once. Chunks of undigested leaf are eliminated when they defecate, have a bowel movement, then they eat their waste and digest it again so that more nutrients can be removed.

CONSERVATION STATUS

Populations of ringtail and greater gliding possums vary in how threatened they are by extinction. Some species, like the lemuroid ringtail possum, are widespread and have large populations. They are not considered threatened. Other species are threatened by the shrinking size of their habitat. The d'Albertis's ringtail possum and the golden ringtail are among this group. No species in this family is currently considered endangered, and they are not protected under law on the island of New Guinea.

GREATER GLIDER (Petauroides volans): SPECIES ACCOUNTS

Physical characteristics: The greater glider is one of the largest of the gliding possums, with lengths that range between 35 and 41 inches (90 and 105 centimeters). They weigh between 2 and 3.8 pounds (0.9 and 1.7 kilograms). Their fur is dark brown on most of the body except the underside, which is white. They have a long bushy tail that allows them to turn in mid-air and a gliding membrane that runs from their elbows to their ankles and acts as a parasail.

Geographic range: Greater gliders are found in eastern Australia.

Habitat: Greater gliders live in the both dry and wet forests, but not rainforests.

Diet: Greater gliders are herbivores. Their primary food is the leaves of trees and some parts of other plants.

Behavior and reproduction: Greater gliders are able to glide for distances up to 330 feet (100 meters) and even make 90 degree turns while in the air by using their tail like a rudder. The female gives birth to one young each year between March and June. The young stay in their mother's pouch for 120 days, after which they ride on their mother's back for three more months.

Greater gliders and people: Greater gliders have no known importance for people.

Conservation status: Greater gliders are classified as Vulnerable, facing a high risk of extinction in the wild. ∎

COMMON RINGTAIL (Pseudocheirus peregrinus): SPECIES ACCOUNTS

Physical characteristics: Common ringtails range in length from 24 to 28 inches (60 to 70 centimeters) and weigh between 1.5 and 2.4 pounds (0.7 and 1.1 kilograms). Ringtails have gray-brown fur with lighter fur on the belly. Their tail is long, thin, and pale on the end.

Geographic range: Common ringtails can be found along the eastern coast of Australia from the northern-most tip, down to the southern tip near Tasmania. They are also found throughout Tasmania and the Bass Straight islands.

Habitat: Common ringtails live among any type of vegetation with dense underbrush. This can mean a wide variety of locations, from rainforests to Australian coastal wasteland.

Diet: Common ringtails are herbivores meaning that they eat mainly leaves, fruits, and flowers.

Behavior and reproduction: Common ringtails are nocturnal. Common ringtails build large nests, often next to each other or in groups. Females give birth to two young at a time between April and November. After birth the young live in their mother's pouch for three months. Males take part in the care of the young after they leave the pouch. Once young are six months old, they leave their parents.

Common ringtail and people: Common ringtails in the areas around where people live have been known to eat flowers and other decorative plants in gardens.

Conservation status: Common ringtails are not threatened. ∎

FOR MORE INFORMATION

Books:

Kerle, Anne. Possums: The Brushtails, Ringtails and Greater Gliders. Sydney, Australia: University of New South Wales Press, 2001.

Russell, Rupert. Spotlight on Possums. St. Lucia, Australia: University of Queensland Press, 1980.

Steiner, Barbara A. A Field Guide to the Mammals of Australia. Oxford, U.K.: Oxford University Press, 2001.

Web sites:

"Common Ringtail Possum." Tasmanian Department of Primary Industries, Water and Environment: Parks & Wildlife. http://www.dpiwe.tas.gov.au/inter.nsf/WebPages/BHAN-53J3P5?open (accessed on June 30, 2004).

"Sugar Glider." Tasmanian Department of Primary Industries, Water and Environment: Parks & Wildlife. http://www.dpiwe.tas.gov.au/inter.nsf/WebPages/BHAN-53J8XS?open (accessed on June 30, 2004).