In earlier days marsupial animals lived in almost all parts of the world, for there are very few countries in which their fossil remains have not been discovered. But now they are almost entirely restricted to Australia, the only exceptions being the opossums, which are found in America. KANGAROOS The largest, and in some respects the most interesting, of the marsupials are the kangaroos. In some ways they are rather like gigantic hares. But their front legs are so much smaller than the hinder ones that they cannot run on all fours, but travel by means of a series of leaps, skipping about, in fact, instead of running. And besides this they have very long and stout tails, which serve to support them when they are sitting upright, and also help them to balance their bodies when they are leaping. The male kangaroo, which is often known as the "boomer," or as the "old man," is very much larger than the female, sometimes attaining to a total length of eight feet six inches, or even nine feet, nearly half of which is occupied by the tail. But when he is sitting upright he is nearly as tall as a tall man. The female is about two feet shorter. Although it is obliged to hop along instead of running, the kangaroo is a very swift animal, and can only be run down by fast and powerful dogs. At every leap it covers about fifteen feet of ground, the distances between the holes which its great claws make in the ground being as regular as if they had been marked out with a measuring-tape. These huge claws are very formidable weapons, and the kangaroo well knows how to use them. As a rule it is a very timid animal, and when it is attacked its first idea is always to seek safety in flight. But if it is driven to bay it takes up its post with its back against a tree, so that it cannot be approached from behind, and quietly awaits the onslaught of its enemies. Then, as soon as one of them comes within reach, it kicks suddenly out with one of its hind feet, delivering its stroke with such force that the great sharp claw has been known to rip up the body of a large dog from end to end, and to stretch the poor beast dying upon the ground. For this reason hounds which are used in kangaroo-hunting are made to wear collars of twisted steel chain, to protect them from the stroke of their quarry. Sometimes, too, when a hunted kangaroo finds that it cannot escape simply by speed, it will wade into a pool or river, wait till the dogs swim up to it, and then seize them with its fore limbs one after another, and hold them under water till they are drowned. Although they are not large, these front limbs are wonderfully strong, and if even a powerful man were to be embraced by them he would find it very difficult to make his escape.