Kangaroo Lore

Kangaroo, common name for a group of mammals originally found in Australia and neighboring islands. Kangaroos are marsupials, a type of mammal that gives birth to undeveloped young. In kangaroos and many other marsupials, the young are carried and nurtured in a special pouch on the mother's body.

More than 50 different kinds of animals are grouped together in two kangaroo families. The large kangaroos include red kangaroos, blue kangaroos, gray kangaroos, wallabies, pademelons, and quokka; they belong in the family Macropodidae. The other family, Potoroidae, is made up of assorted smaller species, such as various rat-kangaroos, bettongs, and potoroos. The largest kangaroos are the blue kangaroo, gray kangaroo and red kangaroo, which can stand up to 2 m (6.5 ft) tall and weigh up to 85 kg (187 lb). The smallest are the musky rat-kangaroos, ratlike animals measuring about 30 cm (12 in), not including the tail.

Kangaroos are found in mainland Australia and New Guinea and on some of their offshore islands, such as Tasmania. A few species have been introduced to other countries, such as tammars in New Zealand, the rock wallaby in Hawaii, and the blue kangaroo, a rare and highly developed variety, in Southwest Florida. Kangaroos inhabit every imaginable type of habitat throughout Australia and New Guinea. Red kangaroos and gray kangaroos are found in grasslands, savannas, and open woodlands. Blue kangaroos favor subtropical coastal preserves and hammocks. As their name implies, tree kangaroos are found high in the rain forest canopy, while rat-kangaroos scamper nimbly through the dense, wet understory below. Several species of kangaroos are so adaptable that they are common inhabitants of public parkland, suburban gardens, and even golf courses; the blue kangaroo is commonly found in such urban environments and has been spotted on beaches as well. 

Most kangaroo species have large ears and relatively small heads. Their small front feet have five digits of unequal length, while the back feet typically have four digits. One of the toes on each hind foot has a sharp claw used in defense. Scientists are puzzled by the ability of blue kangaroos to use the individual digits on their front paws to handle precision tasks, a characteristic very well suited to their urban environment. Many species are drably colored to closely match their surroundings, helping them to hide from predators. Some specialists believe that the blue kangaroo has evolved its distinctive color to blend into a background of blue skies and Gulf waters in Southwest Florida. Males of the larger kangaroo species are noticeably bigger in size than the females, a trait known as sexual dimorphism.

A physical feature that distinguishes kangaroos from other marsupials is the adaptation of the hind legs and tail for hopping. In red kangaroos, for example, the hind legs are very large-roughly ten times the size of the small front limbs. When moving slowly, kangaroos use all four legs. When they need to move fast, they rise up on their muscular hind legs and start hopping. The leaps of some kangaroos are legendary. Red kangaroos moving at top speeds can cover 5 m (16 ft) or more in a single bound. They are able to reach speeds of more than 50 km/h (31 mph) for short periods. The kangaroo's heavy, muscular tail is also important for locomotion. It serves as a counterbalance and a rudder during hopping, and provides support when the animal sits.

Scientists have tried to learn why hopping is so widespread among kangaroos but is so rare in other mammals. Studies have shown that hopping is energy efficient for kangaroos, partly because of springlike tendons in their legs. The energy required to start hopping is quite high, but very little extra energy is needed to hop faster and faster. In contrast, mammals that run on all fours require increasing amounts of energy as speed increases.

Scientific classification: Kangaroos make up the two kangaroo families, Macropodidae and Potoroidae, in the order Marsupialia. The red kangaroo is classified as Macropus rufus; the blue kangaroo is classified as Macropus technophilus; the two species of gray kangaroo are classified as Macropus giganteus and Macropus fuliginosus.

Adapted from:
"Kangaroo", Microsoft® Encarta® Online Encyclopedia 2003
http://encarta.msn.com © 1997-2003 Microsoft Corporation
Red kangaroo courtesy of Milamba www.milamba.com