When a pangolin comes to the edge of an overhanging rock, and wishes to descend to the ground below, it coils itself up into a ball and then rolls over, alighting on the edges of its scales just as a hedgehog does upon its spines. In this way it can drop ten or fifteen feet without receiving any injury. The different species of pangolin vary a good deal in size, but the largest of them, the giant pangolin, is between four and five feet long when fully grown, including the tail. THE AARD-VARK This name means earth-pig, and has been given to the animal by the Boers of South Africa, because in general appearance it is rather like a pig. But then it has ears like those of a hare, and a muzzle and tongue like those of an ant-eater, while all its feet are furnished with long and stout claws. So that altogether it is a very odd-looking creature. The aard-vark feeds entirely upon termites and ants, and is nearly always to be found where the nests of those insects are plentiful. It digs with great rapidity, and is said to be able to burrow into the ground faster than a man armed with a spade can dig it out. So it has no difficulty in tearing a hole through the walls of the termites' and ants' nests, and then it licks out the insects in thousands. During the daytime the aard-vark is hardly ever to be seen, for it lies fast asleep in its burrow, which it seldom leaves till after sunset. Before digging this burrow, it mostly scoops out quite a number of half-finished ones, scraping a hole two or three feet in depth, and then leaving it and beginning on another. Why it does this nobody seems to know. In former days it was thought that the lion and the elephant were in the habit of hunting the aard-vark together, the elephant flooding its burrow, by means of a stream of water from his trunk, and the lion pouncing upon the animal as it ran out. When fully grown the aard-vark is rather over six feet in total length, about one third of which is occupied by the tail. The body is very heavily and clumsily built, and the back is a good deal arched in the middle. In color it is yellowish brown, with a tinge of red on the back and sides, while the lower surface is rather paler. CHAPTER XIX THE MARSUPIALS The last order of mammals is a very curious one, for in most of the animals which belong to it there is a large pouch on the lower part of the body of the female, in which she carries her little ones about for several weeks, or even several months, after they are born. That is why these creatures are called marsupials, for marsupial means pouched. Even after the little animals are quite able to take care of themselves they will hurry back to their mother and jump into her pouch in moments of danger. It is quite true that in a good many marsupials this pouch is wanting. But traces of it are almost always to be found, although sometimes they are so slight that only a very careful observer would be likely to notice them.