KANGAROO, an Australian marsupial of the family Macropodida. The word is derived from a native name of the giant kangaroo. The Macropodidce are readily distinguished from other marsupials by their shape. The head is small, with large mule-like ears; the neck slender, the trunk narrow before and very massive behind; the fore limbs small and weak with five toes and used chiefly as hands; the hind limbs long, extremely powerful, four-toed and serving as the chief organs of locomotion; and the tail thick, heavy and muscular, serving to support the body, in combination with the hind legs, as on a tripod. The dentition is note worthy, having a somewhat rodent-like appear ance. There are three pairs of incisors above, presenting a sharp cutting edge which the sin gle pair of lower incisors passes like the blade of a shears. The molars are flat-crowned. The kangaroos are strictly vegetarian, and in Aus tralia represent the deer, antelopes and hares of other regions. About 50 species belonging to 12 or 15 genera have been described from Aus tralia and the neighboring islands. The giant kangaroo (Macropus giganteus), the largest, is frequently exhibited in zoological gardens. This, the first of the kangaroos known to white men, was discovered by Captain Cook during his exploring voyage in 1770, and was described under the name Didelphys 9igantea from speci mens brought home by him. When standing erect in the attitude of scenting danger it is nearly as tall as a man, and when in full flight propels itself by bounds of 12 to 15 feet. It often gathers into large bands, or did so form erly, when more abundant. On account of its destructiveness to herbage on the sheep-ranges, as well as for sport, it is much hunted by the colonists, a favorite method being coursing. When brought to bay by the hounds it proves no mean antagonist, and frequently kills a dog by seizing it in its arms and ripping it open with the great hind toe. As in other kangaroos
the hind feet have a peculiar structure; the fourth toe is enormously developed and fur nishes almost the sole support ; the fifth is of moderate size; in sharp contrast the second and third toes are minute, slender and bound to gether so that only their sharp claws project from the skin, their only function being to comb and cleanse the fur. The one or two young are born in an exceedingly helpless state, and after being placed in the vouch of the female remain attached by their mouths to the nipples for several weeks or months; at first they are quite incapable of sucking, and the milk is injected into their mouths by the period ical contraction of the muscles of the mammary glands. Even after they are able to run about, they return to the mother's pouch for temporary rest and shelter. Closely related are the red kangaroo (M. rufus) and other species inhabit ing the mountains, and the numerous species of large and small wallabies or brush-kangaroos, some of which inhabit New Britain and New Guinea, as well as Australia. The genus Den drolagus includes the arboreal tree-kangaroos. The large rock-kangaroos (genus Petrogale) dwell among rocks, leaping about them wit great agility and using their long tails like a balancing-pole. The rat-kangaroos (sub-family Potorina') are a small group of species some what resembling rats and rabbits in size and habits. They are nocturnal and obtain their food largely by digging roots. Fossil forms are ex humed from the Pleistocene rocks of Australia very similar to modern genera, but some of the older ones were much larger than any ex isting species. Consult Waterhouse, 'Nat. Hist. of the Mammalia). (London 1846) ; Gould, 'Monograph of the Macropodide (London 1841) ; and 'Mammals of Australia' (London 1863) ; Flower and Lydekker, 'Mammals Liv ing and Extinct' (London 1891) ; Ingersoll, 'Life of Mammals' (New York 1906), and systematic works.