Kangaroos and Wallabies

One fossil kangaroo, Procoptodon goliah, was at least 10 ft (3.1 m) tall and weighed about 500 lb (227 kg). Today, the largest of the species is the male red kangaroo, which may have a head-and-body length of almost 6 ft (1.8 m), with a tail about 3.5 ft (107 cm) long. It may weigh 200 lb (90 kg).

Fourteen species of living kangaroos belong to the genus Macropus. They include the largest living marsupials. In varying contexts and times they have been regarded as pests, or as among the treasures of Australia. Farmers have argued that kangaroos take food from sheep and cattle, but actually kangaroos tend to select different plants from domestic livestock. Today, only a few are seen near urban areas, but they are widespread in the countryside, where they are still a favorite target of hunters, who sell their meat and skins.

The eastern gray kangaroo and its western relative (M. fuliginosus), which is actually brown in color, occupy forest areas throughout the eastern half and the southwest region of Australia. The forest-living species mostly eat grasses. Their young are born at more predictable times than those of the red kangaroos and they take longer to develop. They spend about 40 weeks in the pouch, and the mother does not mate again until the joey becomes independent and mobile.

The red kangaroo shares the western gray kangaroo's habitat. As European settlers developed the land, forests were cut, reducing habitat for the gray kangaroos, but increasing the red kangaroo populations. Only the male red is actually brick red; the female is bluish gray, giving it the nickname "blue flier." It has the ability to care for three young at different stages of their lives at once. It can have an egg in diapause in its uterus, while a tiny pouch embryo can be attached to one teat. Then, another teat elongates so that it is available outside the pouch, where an older, mobile offspring can take it for nourishment. This situation probably evolved in response to the dryness of the red kangaroo's desert environment, which can easily kill young animals.

In the continental interior, the red kangaroo lives in open dry land, while wallaroos, also called euros (M. robustus), live around rock outcroppings. The wallaroos, which have longer and shaggier hair than the larger kangaroos, are adapted for surviving with minimal water for nourishment. When water is not available, the animal reduces the body's need for it by hiding in cool rock shelters, and their urinary system concentrate the urine so that little liquid is lost.