A kangaroo is a marsupial from the family Macropodidae (macropods, meaning 'large foot'). In common use the term is used to describe the largest species from this family, especially those of the genus Macropus, Red Kangaroo, Antilopine Kangaroo, Eastern Grey Kangaroo and Western Grey Kangaroo. Kangaroos are endemic to the country of Australia. The smaller macropods are found in Australia and New Guinea.
Larger kangaroos have adapted much better to changes brought to the Australian landscape by humans and though many of their smaller cousins are endangered, they are plentiful. They are not farmed to any extent, but wild kangaroos are shot for meat, leather hides, sport, and to protect grazing land for sheep and cattle. Although there is some controversy, harvesting kangaroo meat has many environmental and health benefits over traditional meats.
The kangaroo is a national symbol of Australia: its emblem is used on the Australian coat of arms, on some of its currency, as well as by some of Australia's best known organisations, including Qantas. The kangaroo is important to both Australian culture and the national image and consequently there are numerous popular culture references.
Biology and behaviour
Kangaroos are the only large animals to use hopping as a means of locomotion. The comfortable hopping speed for Red Kangaroo is about 20–25 km/h (13–16 mph), but speeds of up to 70 km/h (44 mph) can be attained, over short distances, while it can sustain a speed of 40 km/h (25 mph) for nearly 2 kilometres (1.2 mi). This fast and energy-efficient method of travel has evolved because of the need to regularly cover large distances in search of food and water, rather than the need to escape predators. To move at slow speeds, it uses its tail to form a tripod with its two forelimbs it then raises its hind feet forward.
The average lifespan of kangaroos averages at 6 years in the wild to in excess of 20 years in captivity, varying by species. Most individuals, however, do not reach maturity in the wild.
Different species of kangaroos have different diets, although all are strict herbivores. The Eastern Grey Kangaroo is predominantly a grazer eating a wide variety of grasses whereas some other species (e.g. the Red Kangaroo) include significant amounts of shrubs in the diet. The smaller species of kangaroos also consume hypogeal fungi. Many species are nocturnal and crepuscular, usually spending the days resting in shade and the cool evenings, nights and mornings moving about and feeding.
Because of its grazing, kangaroos have developed specialized teeth. Its incisors are able to crop grass close to the ground, and its molars chop and grind the grass. Since the two sides of the lower jaw are not joined together, the lower incisors are farther apart, giving the kangaroo a wider bite. The silica in grass is abrasive, so kangaroo molars move forward as they are ground down, and eventually fall out, replaced by new teeth that grow in the back.