That strange habit which the bower-birds have of bringing all sorts of things—such as bleached bones, shells, etc.—to the places they make, is practised also by at least one species of mammal—the Bizcacha or Vizcacha, namely, an animal whose home _par excellence_ is the pampas of South America, where it takes the place of the allied prairie-dog, or marmot, of the northern continent. It is a quaint-looking animal, something like a rabbit, Darwin thought, but with larger gnawing teeth, and a much longer tail. Like the rabbit, too, it is social in its habits, and makes a burrow of huge size, with a mound piled up all around it. It is to this mound that the bizcacha brings almost everything that it finds lying about, which is not too large for it to drag or carry, and just as in Australia one looks for anything one has lost in the habitations of the bower-birds, so on the pampas the first thing to do is to search the neighbouring bizcacheras—to use the Spanish word for a settlement or colony of these animals. Thus, if a Spanish gentleman should happen to drop his watch whilst riding, or a herdsman his whip, he is not much put out about it, even if it happened on a dark night. Next morning he rides again along the track of his horse’s hoofs, and comes back with the watch in his pocket or the whip in his hand. Nobody knows why the bizcacha does this, or, to talk in a more scientific way, what is the origin of the habit. There can be no doubt whatever that the flowers or shells brought to the gardens or play-houses of the bower-birds answer the purpose of decoration, and are thought pretty by the birds. The bizcacha may have the same idea, but if so it seems funny that no other member of his family, and, indeed, as far as I am aware, no other mammal at all, should act similarly, or seem attracted by objects in themselves, independently of any use they can be put to. Nor does the bizcacha play with these things—at least I have not heard of his being seen to do so. He just pulls them to his mound and then seems to pay no further attention to them. Another explanation has been suggested[4] which I think is more likely to be the real one. The bizcacha is extremely careful in clearing the ground, not only round its own burrow, but all about the village, as a collection of bizcacha burrows may be called. This he can only do by removing all objects, whether growing or merely lying about, but it is his instinct instead of dragging them away from the village into the country at large, to drag them to his mound and get rid of them there. Perhaps if he were to carry them off he would not know when to stop. The mound gives him a definite place to bring them to, and, moreover, he feels safer going towards his burrow than away from it. However, whatever may be his reason, this is what the bizcacha does. He is an animal that makes a mound or hill of earth, and then brings everything he can find to that mound, and lays it on the top of it.