The Kangaroo Family

Kangaroos are Australia's best-known animals. Since they were first seen by European settlers - who were amazed at such strange animals - a lot has happened to these unique creatures. There are now more of some kangaroo species, generally the larger ones, than when the European settlers arrived. Other species are gone forever, made extinct by surroundings that were changed too much for them to survive. Many of less well known surviving species are also decreasing in number and may become extinct if we do not take the necessary actions. The following information gives general facts about kangaroo biology, the different species, where they are found and what is bieng done to protect

Kangaroos, and their close relatives, vary greatly in size, ranging in weight from 500 grams to 90 kilograms. There are at least 69 different types (called species) of kangaroo. These species are found naturally in the wild only in Australia and New Guinea, although feral populations of some species have been introduced in New Zealand, Great Britain and Hawaii.

Getting Around Kangaroos of all sizes have one thing in common - powerful back legs with long feet. They are distinguished from other animals by the way they hop on these strong back legs. Only a few other small mammals, such as hopping mice, do this. Hopping uses slightly less energy than four-footed running, but this advantage is lost at low speed. To move slowly, kangaroos balance on their front paws and tail, and then swing their hind legs forward in a pendulum motion. One of the many odd things about kangaroos is that, on land, they can only move their hind feet together but when swimming they can kick each leg independently. Tree-kangaroos can move each hind leg separately when climbing. It is also interesting to note that, while several species of kangaroos have tails that can wrap around and carry nesting material such as grass and small branches, not one of the tree-kangaroos has the ability to grasp branches with its tail.

Development of the Young in the Pouch Kangaroos have adapted to the varied conditions across Australia in many ways. One of the most unusual, is the way females of some species can delay the progress of pregnancy. In this way the female is ready to give birth to a replacement for the young in her pouch if it dies early, or within a week of when it permanently leaves the pouch. This ability to delay births means that there can be up to 12 months between a mating and the birth of the young one resulting from that mating (when the normal gestation period is less than 35 days). It also means that the species can best respond to periods of drought and plenty. Species which have this unusual ability normally mate again soon after the female gives birth. The tiny newly born kangaroo (less than 25 mm long) moves unaided into its mother's pouch and attaches itself to one of four teats. During the early stages of pouch life the young is permanently attached to the teat, but as it matures and begins to grow hair it also develops the ability to release and reattach itself to the teat. In the late stages of pouch life, once it has a thin covering of fur, the young one begins to explore the outside world for increasing lengths of time until eventually it is old enough to be excluded permanently from the pouch. Complete weaning may take a number of months more after the young has permanently left the pouch. If the mother gives birth during this time, the newborn young will attach itself to a different teat to that being used by the older young. It is remarkable that when this happens the mother produces two different kinds of milk for the two different-aged young.

Different Species for Different Habitats Australia is a large country with a wide range of landscapes and climates. Kangaroos, rock-wallabies, pademelons, rat-kangaroos, potoroos and others have found all sorts of living areas, or habitats, to suit them across the continent.