A kangaroo is a marsupial from the family Macropodidae. In common use the term is used to describe the largest species from this family, the Red Kangaroo, the Antilopine Kangaroo, and the Eastern and Western Grey Kangaroo of the Macropus genus.
The word kangaroo derives from the Guugu Yimidhirr word gangurru, referring to a grey kangaroo.The name was first recorded as "Kangooroo or Kanguru" on 4 August 1770, by Lieutenant (later Captain) James Cook on the banks of the Endeavour River at the site of modern Cooktown, when HM Bark Endeavour was beached for almost seven weeks to repair damage sustained on the Great Barrier Reef.
A common legend about the kangaroo's English name is that it came from the Aboriginal words for "I don't understand you." According to this legend, Captain James Cook and naturalist Sir Joseph Banks were exploring Australia when they happened upon the animal. They asked a nearby local what the creatures were called. The local responded "Kangaroo", meaning "I don't understand you", which Cook took to be the name of the creature.
Europeans have long regarded Kangaroos as strange animals. Early explorers described them as creatures that had heads like deer (without antlers), stood upright like men, and hopped like frogs. Combined with the two-headed appearance of a mother kangaroo, this led many back home to dismiss them as travellers' tales for quite some time.
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 two kilometres. 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.
Because of its long feet, it cannot walk normally. To move at slow speeds, it uses its tail to form a tripod with its two forelimbs. It then raises its hind feet forward, in a form of locomotion called "crawl-walking."
The average life expectancy of a kangaroo is about 4–6 years, with some living until they are about 23.... (more on www.wikipedia.org)