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.
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.
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.
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-atfoot 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.
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.