Skilful diggers prepare burrows with several entrances; some even arrange several rooms, each for a special object. The Otter seeks its food in the water, and actively hunts fish in ponds and rivers. But when fishing is over, it likes to keep dry and at the same time sheltered from terrestrial enemies. Its dwelling must also present an easy opening into the water. In order to fulfil all these conditions, its house consists first of a large room hollowed in the bank at a level sufficiently high to be beyond reach of floods. From the bottom of this keep a passage starts which sinks and opens about fifty centimetres beneath the surface of the water. It is through here that the Otter noiselessly glides to find himself in the midst of his hunting domain without having been seen or been obliged to make a noisy plunge which would put the game to flight. If this were all, the hermetically-closed dwelling would soon become uninhabitable, as there would be no provision for renewing the air, so the Otter proceeds to form a second passage from the ceiling of the room to the ground, thus forming a ventilation tube. In order that this may not prove a cause of danger, it is always made to open up in the midst of brushwood or in a tuft of rushes and reeds.
Marmots also are not afraid of the work which will assure them a warm and safe refuge in the regions they inhabit, where the climate is rough. In summer they ascend the Alps to a height of 2,500 to 3,000 metres and rapidly hollow a burrow like that for winter time, which I am about to describe, but smaller and less comfortable. They retire into it during bad weather or to pass the night. When the snow chases them away and causes them to descend to a lower zone, they think about constructing a genuine house in which to shut themselves during the winter and to sleep. Twelve or fifteen of these little animals unite their efforts to make first a horizontal passage, which may reach the length of three or four metres. They enlarge the extremity of it into a vaulted and circular room more than two metres in diameter. They make there a good pile of very dry hay on which they all install themselves, after having carefully protected themselves against the external cold by closing up the passage with stones and calking the interstices with grass and moss.
In solitary woods or roads the Badger (Meles), who does not like noise, prepares for himself a peaceful retreat, clean and well ventilated, composed of a vast chamber situated about a metre and a half beneath the surface. He spares no pains over it, and makes it communicate with the external world by seven or eight very long passages, so that the points where they open are about thirty paces distant from one another. In this way, if an enemy discovers one of them and introduces himself into the Badger’s home, the Badger can still take flight through one of the other passages. In ordinary times they serve for the aëration of the central room. The animal attaches considerable importance to this. He is also very clean in his habits, and every day may be seen coming out for little walks, having an object of an opposite nature to the search for food. This praiseworthy habit is, as we shall see, exploited by the Fox in an unworthy manner.
The Fox has many misdeeds on his conscience, but his conduct towards the Badger is peculiarly indelicate. The Fox is a skilful digger, and when he cannot avoid it, he can hollow out a house with several rooms. The dwelling has numerous openings, both as a measure of prudence and of hygiene, for this arrangement enables the air to be renewed. He prepares several chambers side by side; one of which he uses for observation and to take his siesta in; a second as a sort of larder in which he piles up what he cannot devour at once; a third, in which the female brings forth and rears her young. But he does not hesitate to avoid this labour when possible. If he finds a rabbit warren he tries first to eat the inhabitants, and then, his mind cleared from this anxiety, arranges their domicile to his own taste, and comfortably installs himself in it. In South America, again, the Argentine Fox frequently takes up permanent residence in a vizcachera, ejecting the rightful owners; he is so quiet and unassuming in his manners that the vizcachas become indifferent to his presence, but in spring the female fox will seize on the young vizcachas to feed her own young, and if she has eight or nine, the young of the whole village of vizcachas may be exterminated.
The Badger’s dwelling appears to the Fox particularly enviable. In order to dislodge the proprietor he adopts the following plan. Knowing that the latter can tolerate no ordure near his home, he chooses as a place of retirement one of the passages which lead to the chamber of the peaceful recluse. He insists repeatedly, until at last the Badger, insulted by this grossness, and suffocated by the odour, decides to move elsewhere and hollow a fresh palace. The Fox is only waiting for this, and installs himself without ceremony.
The Vizcacha (Lagostomus trichodactylus) is a large Rodent inhabiting a vast extent of country in the pampas of La Plata, Patagonia, etc. Unlike most other burrowing species, the Vizcacha prefers to work on open level spots. On the great grassy plains it is even able to make its own conditions, like the Beaver, and is in this respect, and in its highly-developed social instinct, among the two or three Mammals which approach Man, although only a Rodent, and even in this order, according to Waterhouse, coming very low down by reason of its marsupial affinities.
The Vizcacha lives in small communities of from twenty to thirty members, in a village of deep-chambered burrows, some twelve or fifteen in number, with large pit-like entrances closely grouped together, and as the Vizcachera, as this village is called, endures for an indefinitely long period, the earth which is constantly brought up forms an irregular mound thirty or forty feet in diameter, and from fifteen to thirty inches above the level of the road; this mound serves to protect the dwelling from floods on low ground. A clearing is made all round the abode and all rubbish thrown on the mound; the Vizcachas thus have a smooth turf on which to disport themselves, and are freed from the danger of lurking enemies.
The entire village occupies an area of one hundred to two hundred square feet of ground. The burrows vary greatly in extent; usually in a Vizcachera there are several that, at a distance of from four to six feet from the entrance, open into large circular chambers. From these chambers other burrows diverge in all directions, some running horizontally, others obliquely downwards to a maximum depth of six feet from the surface; some of these galleries communicate with those of other burrows.
On viewing a Vizcachera closely, the first thing that strikes the observer is the enormous size of the entrances to the central burrows in the mound; there are usually several smaller outside burrows. The entrance to some of the principal burrows is sometimes four to six feet across the mouth, and sometimes it is deep enough for a tall man to stand in up to the waist.
It is not easy to tell what induces a Vizcacha to found a new community, for they increase very slowly, and are very fond of each other’s society. It is invariably one individual alone who founds the new village. If it were for the sake of better pasture he would remove to a considerable distance, but he merely goes from forty to sixty yards off to begin operations. Sooner or later, perhaps after many months, other individuals join the solitary Vizcacha, and they become the parents of innumerable generations in the same village: old men, who have lived all their lives in one district, remember that many of the Vizcacheras around them existed when they were children.