GLIDING AND STRIPED POSSUMS: Petauridae

PHYSICAL CHARACTERISTICS

Gliding and striped possums are arboreal, which means that they live in trees. They are also nocturnal, meaning they are active at night and sleep during the day, often in hollow trees. Members of this family are medium-sized. They measure between 12 and 31 inches (32 to 78 centimeters) long and weigh between 3 and 25 ounces (95 to 720 grams).

As the name of this family suggests, there are two major types of Petauridae. These two types are organized into groups called subfamilies. One subfamily is called Petaurinae, and the other is called Dactylopsilinae. The Petaurinae subfamily is the group known as the gliding possums. The Dactylopsilinae are the striped possums. Although they are closely related, these two subfamilies look quite different from each other.

Gliding possums are gray, brown, or cream colored. They have a membrane (a thin layer of skin) between their front and rear legs that stretches from their wrist to their ankle. When they leap from branch to branch, they spread this membrane out like a bed sheet in order to glide. Gliding possums also have a bushy tail that is used for steering while in the air. The end of their tail is prehensile, which means that it can be used for grasping branches.

Striped possums are black with two white stripes that run along their back like a skunk. Also like a skunk, these animals have a strong and unpleasant odor that is produced by several glands or organs that secrete chemicals from the body. Striped possums have five toes on their front paws. The fourth toe is much longer than the rest. They use this to tap tree trunks to find hollow spaces where insects might be hiding. Once they find the insects, they use this toe to dig them out. They also have very strong front teeth that help them to puncture the bark of trees.

GEOGRAPHIC RANGE

Striped possums live in New Guinea. One species is also found in the rainforest on the northern tip of Australia that is closest to New Guinea. Gliding possums also live in New Guinea and Australia, but are found in a much wider area. They live both on the northern and eastern coast of Australia and on the island of Tasmania.

HABITAT

Gliding and striped possums live in many different types of forests, from dense rainforests to open forests where trees are spread far apart.

DIET

Gliding possums are omnivorous meaning they eat both plants and animals. They feed mostly on sap from trees, as well as nectar and blossoms. Some species of gliding possums are able to bite into tree bark in order to get the sap. Others feed off sap that leaks from wounds in trees made by other species.

Striped possums are insectivorous, meaning that they mainly eat insects. They use their long fourth finger to tap trees and rotting logs to find the hollow spots where insect larvae (LAR-vee; young developing insects) are living. They then use their strong front teeth to dig into the tree and their fourth finger to pull out the larvae.

BEHAVIOR AND REPRODUCTION

Striped possums live alone and do not form social groups. They are believed to be territorial. This means that they stay in a particular area and defend it against other members of their species. Gliding possums are more social and live in family groups and share their nests. These groups are made up of variable numbers of adult males and females. Within these groups, both males and females develop a system of ranking known as a hierarchy (HI-uh-raar-key). Females will aggressively bother other females that are below them in this hierarchy, sometimes causing the death of their babies. Males that are high in this system tend to care for the young when the females are away. Gliding possums are also territorial, because they protect their area from other gliding possums that are not in their group.

Gliding and striped possums are marsupial mammals, which means that they do not have a well-developed placenta. The placenta is an organ that allows the mother to share food and oxygen with developing offspring in her uterus (womb) during pregnancy. As a result, marsupials like these possums are born underdeveloped and need to continue to grow in their mother's pouch for some time after birth before they can survive in the outside world.

All female members of this family have a pouch with two teats (nipples). Two young are born at a time. After the young are born, they crawl to the pouch and attach themselves to one of their mother's teats. After many days, the young emerge from the pouch and live in a nest. During this time, they may be carried around on their mother's back. Information about reproduction is not known for all species, but it is known that for the sugar glider, pregnancy lasts only sixteen days. However, the young remain in the pouch for another sixty days after birth. The young then live in the nest until they are about four months old. In this species the males that live in the group help to care for the young.

GLIDING AND STRIPED POSSUMS AND PEOPLE

The sugar glider is becoming popular as an exotic pet. It is not clear whether these animals make appropriate pets and some countries have placed a ban on importing them from New Guinea. Beyond this species, there is no significant relationship between humans and the members of this family other than scientific study.

ODOR AND TERRITORY

Animals produce odors for many different reasons. In some cases an animal uses odor as protection to ward off potential predators. They also use odor to attract potential mates. In other situations, animals use odors to let other animals know that a particular area is their territory. Gliding and striped possums use odors to mark territory for different reasons. While striped possums are most likely telling other striped possums to stay out of their area, gliding possums use odor to identify members of their group.

CONSERVATION STATUS

Three species in this family are Endangered, facing a very high risk of extinction in the wild: Tate's triok, the mahogany glider, and Leadbeater's possum. Other species, such as the yellow-bellied glider and the squirrel glider are considered Vulnerable, facing a high risk of extinction in the wild. Conservation efforts are underway to identify and protect key habitats of a number of these animals.

SUGAR GLIDER (Petaurus breviceps): SPECIES ACCOUNT

Physical characteristics: Sugar gliders are part of the gliding group (Petaurinae) of this family. They have a membrane that extends from the fifth toe of their back legs to the first finger on their front legs. They spread their arms and legs to make a sail out of the membrane when leaping between branches. Sugar gliders are fairly small measuring between 12 and 15 inches (32 to 42 centimeters) long and weighing between 3.5 to 5.5 ounces (95 to 160 grams). They have two black stripes along the sides of the face, and one black stripe that runs along their back. The rest of their fur is blue-gray, except for on the belly, which has lighter fur.

Geographic range: Sugar gliders live in New Guinea, Tasmania, and in the northern and eastern parts of Australia.

Habitat: Sugar gliders are frequently found living in acacia and eucalyptus trees.

Diet: The sugar glider is an omnivore. It eats tree sap, pollen, insect larvae, and insect-like animals such as spiders.

Behavior and reproduction: Sugar gliders are nocturnal. Using strong legs to launch themselves, they are able to glide up to 230 feet (70 meters). Sugar gliders, like many gliding possums, are social and they live in family groups that are territorial.

Sugar gliders give birth to one or two offspring twice a year. Their pregnancy lasts sixteen days. Pouch stay for the young is about two months, with another two months are spent in the nest. Their lifespan is about fourteen years.

Sugar gliders and people: Despite controversy, sugar gliders are becoming popular as household pets, both in Asia and the United States.

Conservation status: This species is not threatened. There is no serious danger that they will become extinct in the foreseeable future. ∎

FOR MORE INFORMATION

Books:

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

Triggs, Barbara. Tracks, Scats and Other Traces: A Field Guide to Australian Mammals. Oxford, U.K.: Oxford University Press, 1996.

Robinson, Hannah. Australia: An Ecotraveler's Guide. New York: Interlink Books, 2003.

Web sites:

Australian National Parks and Wildlife Service. "Gliding Possums." http://www.nationalparks.nsw.gov.au/npws.nsf/Content/Gliding+possums (accessed on June 30, 2004).