Fig. 59.

The Beaver,[142] a gnawing water-animal.

But the insect-eaters have no water-animal to match the Beaver in sagacity, judgment, or engineering. For here we have a creature not much larger than a good-sized cat, cutting down trees, dragging logs six feet long to the water’s edge, and building with them the most elaborate log-houses and water-dams. With hind feet webbed up to the claws, and his broad tail as a rudder, the beaver has so much swimming power that his fore legs are free to carry and place the wood, while his broad orange-coloured teeth, as sharp as chisels, which grow as fast as he wears them away, are his cutting instruments. With them he gnaws a deep notch in the trunk of a larch or pine or willow, as deep as he dares without fear of its falling, and then going round to the other side, begins work there till the trunk is severed and falls heavily on the side of the deep notch, and therefore away from himself. Then, after stripping off the bark and gnawing the trunk into pieces about six feet long, he uses his fore-paws and his teeth to drag them into position to build his dam. The lighter branches he uses to make his oven-shaped lodge, laying them down in basket-work shape, plastering them with mud, grass, and moss, and lining the chambers with wood-fibre, and dry grass; and the logs he piles up to form dams, lest at any time the stream should flow away and leave the entrances to his home dry. These dams are very skilfully and cunningly formed. He always makes the deep

Footnote 142. Castor fiber.

notch in the trunk on the side near the water, so that the tree in falling comes as near as possible to the stream; then he does not always clear away all the branches, but he and his companions place the logs with these lying down the stream, so that they act as supports to resist the current and prevent the dam being washed away. Thus they make a broad foundation, sometimes as much as six feet wide, and upon this they pile logs and stones and mud till they have made a barrier often ten feet high and more than a hundred feet long.

In this way they clear the woods just round their stream, as if a whole gang of wood-cutters had been there at work; and as the dams check back the water and form broad meres, there are soon swamps on all sides, where peat moss grows and “beaver-meadows” are formed.

Here the beavers live in companies, each in his own chamber with his wife and family, though underground passages often lead from one to the other, and when water-plants and soft bark are scarce, they will often travel some way inland to feed on fruits and grain. But if among the community any are lazy or will not take partners, they are driven out, to find a refuge in holes of the river-banks, where they sulk alone.

In Western Europe, indeed, where they have been so much persecuted, most of the beavers live alone in holes, though communities are still left in parts of Germany, Scandinavia, and Siberia. But in North America they still carry on their true communal life, and those who visit their wonderful settlements will not be surprised to learn that they possess the largest brain for their size of any of the gnawing animals.

Indeed, they would have no rival among rodents if it were not for the clever sagacious rats, and these have probably sharpened their wits by living so long in contact with man, for they are burrowers chiefly in human dwellings, granaries, stables, mines, ships, and every available dwelling-place where they can rob and plunder, and outwit even man himself by working their way into his stores, and acting together in carrying away his goods.

So the insect-eaters and rodents hold their own both by land and water, penetrating, in the forms of bats and mice even to Australia, though the rodents are most widely spread, for except two very rare animals[145] in the West Indian Islands, there are no Insectivora except bats in South America. The bats, however, remind us that both these groups have also found homes above the ground and in the trees. There the rodents have the lovely little Squirrels, which, with their brown red backs, white waistcoats, and graceful bushy tails, scamper up the trees of our English woods. It is very tempting to dwell upon the squirrel, with his little wife, to whom he remains faithful all his life, his beautiful round nest, in which his young are so carefully reared, and his pretty ways as he sits upright gnawing beechnuts or acorns, holding them in his tiny hands. He has made good use of his opportunities, being almost as widely spread as the rat, for there are squirrels of some kind all over the world, wherever there are forests, except in Australia. Several

Footnote 145. Soledon and one of the Shrews.

of them in the East and North America have folds of skin at the side of the body, which, when tightly stretched, by extending the four limbs, enable them to take flying leaps from tree to tree (see Fig. 60). Even without flying, however, the squirrel is so nimble that he manages well to escape his enemies, except some of the birds of prey and the fierce tree-marten and wild cat; and as in cold countries he sleeps soundly in snug holes of a tree till the leaves grow again to give him shelter, he is not often detected even by these.

Fig. 60.

On the tree, the Taguan[146] or flying squirrel, a rodent; Flying below, the Colugo,[147] an insectivorous animal.

Footnote 146. Pteromys Petaurista.

Footnote 147. Galeopithecus volans.

Nevertheless, in tree-life and in the air it is the turn of the insect-eaters to claim the advantage. It is true that the insect-eating Bangsrings,[148] which scamper up the trees in Sumatra and South-East Asia, and were long mistaken for squirrels, are a small family and not of much importance; but what shall we say to the Bats, the only true flying milk-givers? Or what, again, to that curious animal the Colugo or Flying Lemur of the Malay Islands, which belongs to the insect-eaters, and yet has some points like marsupials, some like fruit-bats, and some like the true lemurs? This strange creature, which seems like the remnant of some branch-line from very ancient times, climbs the tree like a squirrel by means of its claws, and then spreading out its limbs displays a broad membrane (see Fig. 60) stretching not only along its sides but across its tail, and from the front of the arms to the neck as in bats, and so sails down from one tree to another. The mother, which Mr. Wallace examined, nurses the little one on her breast just as the lemurs do, while large folds of her skin protects the small, bald, naked little creature, something after the manner of an imperfect pouch. Lastly, while they sometimes feed on insects, the chief diet of these colugos is fruit, like the lemurs, to which group they were once supposed to belong.

* * * * *

But of all modified insect-eaters the most extraordinary are the Bats, which are so different from all the others that they have been placed in a distinct order[149] of their own. Imagine a little creature about three inches long, with a body something like a

Footnote 148. Tupaia.

Footnote 149. Chiroptera.

shrew, large ears, a protruding snout, and plenty of sharp teeth (see Figs. 61 and 62). Let it have a breast bone projecting more than in most milk-givers, and covered with a large mass of muscle as in birds, fitted to move the wings, but having nipples to suckle its young. Let it have large shoulder-blades and collar-bones, a strong upper arm, a very long lower arm (fa, Fig. 61), and four immensely long fingers to its hand (ha), and a short clawed thumb (t). Let its hind legs be short and weak, with a long spur behind the heel (h) of its five-toed feet, and finally let the skin of its body grow on over the arms and long fingers, filling in the space between the elbows and the neck in front, and stretching away behind, over the legs down to the ankle, and on behind the legs, so as to enclose the tail. This skin growing from the back above, and the under part of the body below, will enclose the

bones of the arms, hands, and legs, like a kite with calico stretched on both sides (see Fig. 56, p. 220), and when the long fingers are outspread and the legs opened, no limbs will be seen, but only a small body and head, with an immense expanse of skinny wing, from which the short clawed thumbs and the four toes of the feet stick out before and behind.

Fig. 61.

Skeleton of a Bat.

(Lettered to compare with bird’s skeleton, p. 126).

fa, fore arm; w, wrist; t, thumb; ha, hand; h, heel; f, foot.

Now this creature is no longer like the flying squirrels or the colugo, which can only take floating leaps; for though like them it has only a membrane stretching out from its body, yet this has become a long flexible wing, formed on a widely outstretched arm and abnormally long hand, and moved by powerful muscles like the wings of birds or insects. It is essentially fitted for flitting through the air in search of prey, while it makes but little use of the running power which it possesses in common with all other insect-eaters. If you see a bat moving along the ground, you will acknowledge at once that it is a true quadruped, yet, by its awkward gait as it shuffles along on its clawed thumb and toes, you will judge that it is not an earth-loving animal. Watch it at night on the wing and it is quite another creature; then it will flit about in and out of cracks and crevices, under the eaves, round the haystacks, or among the trees, and never once strike its wings against anything, though it has been proved that it does not trust chiefly to its bead-like eyes to guide it.

Bats have been blinded, their ears stopped with wool, and their noses with sponge dipped in camphor; and yet, without sight, hearing, or smell, they steered quite successfully between outstretched threads or tree-branches, or found their way into a hole in the roof. In truth, as they have become fitted to navigate the air, they seem also to have become sensitive to its currents. Their wings are abundantly supplied with nerves and blood-vessels, and have little rough points all over the surface; their ears have generally a second ear-lobe or leaf within the outer one, and those which have not this have leaves of skin or membrane round their nose. With all these they seem to feel the slightest difference in the air, so as to detect at once whether they are in the open, or whether any resisting object is near them.

Fig. 62.

A Bat walking.

Now it is clear that a creature of this kind, able to chase insects in the air, even in the darkest night, can secure much food that the running insect-eaters can never reach. When the little common English bat, the Pipistrelle, awakes from his day’s sleep, which he has been taking, head downwards, hanging by his feet in some old tree or under the roof of a barn, he finds the gnats and flies abroad, and begins his chase in the twilight—up and down, from side to side he flits, and his wide-open mouth takes in insects at every turn. And by-and-by, as the dark nights come on, the Long-eared Bats begin gradually to stir from their clusters in the barns and old buildings, and, unfolding their wings so as to display their ears as long as their bodies, commit sad havoc among the night-moths. All night long their shrill squeak may be heard, but before day dawns they are away again, and may be found hanging in dense masses by their hind legs to the timbers of some old church belfry, or in caves, or even under the roofs of houses, where they find an entrance by some hole, and go in by hundreds to hang from the rafters.

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