Closely related to the chinchilla is the viscacha, which is found very abundantly in the great pampas districts of South America. It generally lives in little colonies of from twenty to thirty animals, which dig their burrows close together, and heap up the earth which they scrape out into one common mound. These burrows are generally dug in the form of the letter Y, and often a number of them communicate with one another by means of short passages, so that if the little animals feel in want of society they can easily go and see their friends. These colonies are called viscacheras, and in some parts of the Argentine Republic the plains are closely studded with them as far as the eye can reach. Viscachas have a curious way of clearing off all the vegetation that grows near their burrows, and piling up the refuse in a mound near the entrance. They will also collect together any hard objects which they may happen to find, and we are told by Darwin that sometimes quite a barrow-load of bones, stones, thistle-stalks, and lumps of earth may be found outside the entrance to a single burrow, and that a traveler who dropped his watch one evening found it next day by searching the viscacha-mounds in the neighborhood. In appearance the viscacha is not unlike a rather small marmot; but the fur is gray above, with dusky markings, and white below, while the face is crossed by two black bands, with a broad white stripe between them. THE AGOUTI This animal, found in South America and the West Indies, was formerly very plentiful--in some parts literally swarming. But it did so much mischief in cultivated ground that it was trapped and shot in immense numbers, and it has now almost entirely disappeared from many districts in which it once abounded. The first point that strikes one on looking at the agouti is the great length of its hind legs. So long are these limbs, that the animal finds a good deal of difficulty in running downhill, and often tumbles head over heels and rolls for several yards before it can recover its footing. And for the same reason, when it is running at any pace on level ground, it travels along by a kind of gallop, which is really made up of a series of leaps. As the agouti comes out only by night it is a difficult animal to watch, and it is so wary that it cannot be approached without great caution. All the time while it is feeding, it keeps on turning its head first to one side and then to the other, so that it can scarcely ever be taken by surprise. If it should be captured, however, it never seems to fight, and has no idea of using either its sharp teeth or its claws to defend itself. So sometimes it has been thought that an agouti would make a very nice pet. Those who have allowed it to run loose in the house, however, have seldom repeated the experiment, for it will ruin any article of furniture in a very short time, and will cut its way through the stoutest door in a few minutes!