WALLABIES AND KANGAROOS: Macropodidae

PHYSICAL CHARACTERISTICS

Kangaroos and wallabies are marsupial mammals, meaning that they do not produce a well-developed placenta like many familiar mammals. A placenta is an organ that grows inside the mother's uterus (womb) during pregnancy and allows the developing baby to share the mother's food and oxygen. Marsupial mammals are born underdeveloped and they finish developing inside their mother's pouch.

Kangaroos and wallabies are some of the best known Australian marsupials. They have four legs, although their front legs are much smaller and weaker than their large back legs. They usually have long tails and large ears that are either pointed or rounded. They have a head and body length that varies in size from 11 to 91 inches (28 to 231 centimeters), and a tail that ranges in length from 6 to 43 inches (15 to 109 centimeters). They weigh between 3 and 187 pounds (1 to 85 kilograms). In some species the males are much larger than the females. Kangaroos and wallabies have fur that ranges in color from reddish orange to black.

Kangaroos and wallabies have very long, large, strong back feet that allow them to hop at speeds of up to 35 miles per hour (55 kilometers per hour). They have four toes on each of their front and back feet, and the second and third toes on their back feet are fused (attached) together. All of their toes have strong claws.

GEOGRAPHIC RANGE

Kangaroos and wallabies live all over Australia, as well as in parts of New Guinea and some surrounding islands. They have been introduced into Hawaii, New Zealand, Great Britain, and Germany.

HABITAT

Kangaroos and wallabies live in many different habitats. Some live in the tropical rainforest while others live in the grasslands or woodlands. There is almost no area of Australia where at least one species of kangaroo or wallaby does not live.

DIET

Most kangaroos and wallabies are herbivores, which means that they eat only plants. They eat mostly leaves and grass, although some also eat fruit, seeds, and fungi. Some of the smaller species are omnivores, animals that eat both animals and plants. These species eat insects and other invertebrates.

BEHAVIOR AND REPRODUCTION

Kangaroos and wallabies portray a very diverse set of behaviors. Larger species tend to be diurnal, or mostly active during the day. Smaller species tend to be nocturnal, or mostly active at night. Smaller species are often solitary, while larger species often live or feed in groups of up to fifty animals called mobs. A few species are thought to be territorial. They live alone and defend their home area.

When male kangaroos or wallabies fight, they often do so by supporting themselves on their back legs, or even sometimes just their tail for short periods, and attack each other with the strong claws on their front paws. Sometimes they use their strong hind legs to kick out when they are lying on their sides. Females sometimes do this if males try to mate with them and they are not interested.

Like all marsupials, kangaroos and wallabies give birth to young that are not fully developed. These tiny newborns are blind, hairless, and cannot survive on their own. When they are born, they crawl into their mother's pouch where they attach to one of her nipples. This nipple usually swells, keeping the young in place while the mother moves. In some species the mother will let the young out of the pouch for short periods when it gets older. After the young matures, the mother will no longer let it return to the pouch. In some species it becomes what is called a "young-at-foot." During the young-at-foot period, the young kangaroo or wallaby stays with the mother and often suckles, but no longer re-enters the pouch. In some species there is no young-at-foot period.

Kangaroos and wallabies usually give birth to one baby at a time. In some species the female gives birth the same day another young leaves her pouch and becomes a young-at-foot. These species often mate the same day that they give birth, but the fertilized egg stops developing until the pouch-young is nearly old enough to leave the pouch. When the pouch-young is ready to leave, the next baby moves to the pouch.

WALLABIES, KANGAROOS, AND PEOPLE

Many species of kangaroos and wallabies have been hunted for their meat and their skins both by aboriginal (native) Australians and by European settlers. These animals are also important in the Aboriginal culture, where they often play important roles in traditional dreamtime stories. Some sheep ranchers consider kangaroos and wallabies to be a nuisances, because they eat the grass and other plants that the farmers want for livestock grazing.

MEETING THE CHANGING NEEDS OF BABIES

When kangaroo newborns climb into their mother's pouches, they attach themselves to one of her nipples. From this nipple they get the milk that provides the nourishment they need to survive and grow. But the nutritional needs of a newborn are not the same as the nutritional needs of a young animal almost ready to leave the pouch. To make sure their young get the nutrients they need, female kangaroos have milk that changes in content as the young matures. When the young-at-foot and a young in the pouch are both suckling, the two different nipples actually produce two different types of milk, suited to the needs of the two different young.

CONSERVATION STATUS

Four species in this family have already gone extinct. Many others are Endangered, which means that they face a very high risk of extinction in the wild. Others are considered Vulnerable, which means that they face a high risk of extinction in the wild. Some actions are being taken to help particular species, including protecting their habitats and breeding them in captivity, so they may be later reintroduced into the wild.

EASTERN GRAY KANGAROO (Macropus giganteus): SPECIES ACCOUNTS

Physical characteristics: Eastern gray kangaroos have a head and body length that ranges from 38 to 91 inches (97 to 231 centimeters). Their tails range in length from 18 to 43 inches (46 to 109 centimeters). They weigh from 8 to 146 pounds (4 to 66 kilograms). Eastern gray kangaroos have the characteristic body shape of all kangaroos with strong hind legs and large back feet. They have grayish brown fur that is paler on their bellies. Unlike other kangaroos, they have hairy snouts.

Geographic range: The eastern gray kangaroo lives in eastern Australia and in eastern Tasmania.

Habitat: The eastern gray kangaroo lives mainly in grassy woodlands, open grasslands, and forest.

Diet: The eastern gray kangaroo eats mainly grasses.

Behavior and reproduction: The eastern gray kangaroo is diurnal. It usually grazes during the early morning and late afternoon when temperatures are lower. Pregnancy usually lasts for thirty-six days, and the young stay in the pouch for 320 days.

Eastern gray kangaroos and people: It is thought that native Australians probably hunted the eastern gray kangaroo for food. Today, it is illegally hunted for skins and meat.

Conservation status: The eastern gray kangaroo is considered Near Threatened. This classification means that this kangaroo is not currently threatened, but could become threatened. This kangaroo has been affected by illegal hunting for its skins and meat, as well as the destruction of its habitat for agriculture. ∎

RED KANGAROO (Macropus rufus): SPECIES ACCOUNTS

Physical characteristics: Red kangaroos have fur that is reddish brown to blue-gray on most of their body, while their fur is white underneath. Red kangaroos have a head and body length that varies from 29 to 55 inches (74 to 140 centimeters). Their tail length is 25 to 39 inches (64 to 100 centimeters). Their weight varies between 37 and 187 pounds (17 to 85 kilograms). These are the largest kangaroos living today.

Geographic range: Most of Australia, except the coastal regions.

Habitat: Red kangaroos live in grasslands, open woodlands, and open forests.

Diet: Red kangaroos are herbivores. They eat grass and the leaves of shrubs and other plants.

Behavior and reproduction: Red kangaroos are pregnant for 33 days before giving birth. The young live in the pouch for 235 days.

Red kangaroos and people: Red kangaroos are hunted for their skins and meat in some places in Australia. The red kangaroo also has important cultural significance for native Australians, in whose traditional dreamtime stories they often play large parts.

Conservation status: Red kangaroos are not considered threatened. They have benefited from clearing of land for livestock grazing and are one of the few native Australian animals to have increased their population since the coming of European settlers. ∎

BRUSH-TAILED ROCK WALLABY (Petrogale penicillata): SPECIES ACCOUNTS

Physical characteristics: Brush-tailed rock wallabies have fur that is black-brown on their front section and red-brown on their rump. On their underside the fur is paler. They have a tail that is furry and dark colored, characteristics that have contributed to their name. These wallabies have distinctive markings on their heads consisting of a white stripe on their cheeks and a black stripe on their heads. Their head and body length ranges from 20 to 23 inches (51 to 58 centimeters). Their tails range in length from 20 to 28 inches (51 to 71 centimeters). Their weight ranges from 11 to 24 pounds (5 to 11 kilograms).

Geographic range: Brush-tailed rock wallabies live in eastern Australia. They have also been introduced successfully to Hawaii and New Zealand, where self-sustaining colonies now exist.

Habitat: Brush-tailed rock wallabies live in rocky areas in a variety of habitats such as rainforest and woodlands.

Diet: Brush-tailed rock wallabies mainly eat grass, but they also sometimes will eat herbs and fruits.

Behavior and reproduction: Brush-tailed rock wallabies are mostly nocturnal. They sleep in deep cracks in rocks and caves. Females are pregnant for thirty-one days before giving birth. Young live in the pouch for almost seven months before leaving.

Brush-tailed rock wallabies and people: Although brush-tailed rock wallabies have no current economic significance to humans, they were hunted in large numbers for their furs in the late nineteenth and early twentieth centuries.

Conservation status: The brush-tailed rock wallaby is considered Vulnerable, meaning that it faces a high risk of extinction. The main threats to these wallabies are destruction of their habitat from the grazing of livestock and predation from species of animals that are not native to Australian such as red foxes and dingoes (wild dogs). ∎

BRIDLED NAIL-TAILED WALLABY (Onychogalea fraenata): SPECIES ACCOUNTS

Physical characteristics: Bridled nail-tailed wallabies have gray fur with paler gray fur on their bellies. They have a distinctive white stripe on both sides of their body extending from neck to forearms. On the end of the tail is a horny spur, probably inspiring their name. Bridled nail-tailed wallabies range in head and body length from 18 to 28 inches (46 to 71 centimeters), with a tail length that ranges from 15 to 21 inches (38 to 53 centimeters). They have a weight that ranges from 9 to 18 pounds (4 to 8 kilograms).

Geographic range: Currently bridled nail-tailed wallabies have significant populations only in a few places including one location in central Queensland, two places in eastern Australia where they have been reintroduced, two sanctuaries, and a zoo.

Habitat: Bridled nail-tailed wallabies live in areas of woodlands dominated by acacia trees and shrublands.

Diet: Bridled nail-tailed wallabies are herbivores. They eat soft-leaved grasses and other vegetation.

Behavior and reproduction: Bridled nail-tailed wallabies are nocturnal. They use dense vegetation as shelter during the day. Females are pregnant for twenty-three to sixty-two days before giving birth. The young live in the pouch for 119 to 126 days.

Bridled nail-tailed wallabies and people: There is no known significant relationship between the bridled nail-tailed wallabies and people, although scientists think that they have been hunted for their meat and skins.

Conservation status: Bridled nail-tailed wallabies are considered Endangered. This means that they are facing a very high risk of extinction in the wild. Scientists think that the main threats to these wallabies are probably clearing of their habitat for agriculture, and predation by species that are not native to Australia, such as the red fox. ∎

BENNETT'S TREE KANGAROO (Dendrolagus bennettianus): SPECIES ACCOUNTS

Physical characteristics: Bennett's tree kangaroos have dark brown fur on most of their bodies although the fur on the top of their head and shoulders is reddish brown. Their foreheads and snouts are gray. Bennett's tree kangaroos have head and body lengths that range from 27 to 30 inches (69 to 76 centimeters). Their tails range in length from 29 to 33 inches (74 to 84 centimeters). They weigh between 18 and 30 pounds (8 to 14 kilograms).

Geographic range: Bennett's tree kangaroos live on the eastern part of Cape York, which is a peninsula in the far northeast of Australia.

Habitat: Bennett's tree kangaroos live in tropical rainforests.

Diet: Bennett's tree kangaroos eat mainly leaves, although they sometimes also eat fruit.

Behavior and reproduction: Male Bennett's tree kangaroos live alone. They are territorial, which means that they defend their living area against other males of their species, although their home range may overlap with that of several different females. The young remain in the pouch for about 270 days and are young-at-foot for up to two years.

Bennett's tree kangaroo and people: Bennett's tree kangaroos were hunted by native Australians.

Conservation status: Bennett's tree kangaroo is considered Near Threatened. This means that while these kangaroos are not in serious danger yet, they may soon become threatened. ∎

FOR MORE INFORMATION

Books:

Edwards, Bruce. Kangaroos and Wallabies. Hollywood, FL: Ralph Curtis Books, 1993.

Finney, Tim F. Mammals of New Guinea, 2nd ed. Ithaca, NY: Cornell University Press, 1995.

Menkhorst, Frank. A Field Guide to the Mammals of Australia, 2nd ed. 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.

Woods, Samuel G. Sorting Out Mammals: Everything You Want to Know About Marsupials, Carnivores, Herbivores, and More! Woodbridge, CT: Blackbirch Marketing, 1999.

Web sites:

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