Fishes have been taught to assemble at the ringing of a bell, and toads and tortoises to come at the call of their favourite friends. An alligator which was kept tame for several years became so much attached to its master that ‘it followed him about the house like a dog, scrambling up the stairs after him, and showing much affection and docility.’ The favourite friend and companion of this alligator was the cat; and, whenever the cat stretched herself on the floor in front of the fire, the alligator would lie down beside her, with its head on the cat, and go to sleep. ‘When the cat was absent, the alligator was restless, but it always appeared happy when the cat was near it’.[8] Wolves and foxes sometimes cooperate with each other in their hunting expeditions, somewhat as men do in theirs. One of their number will crouch in ambush by the side of a road known to be used by hares or other small animals, and leap on the unsuspecting fugitives when driven that way by others of the hunting band. Many animals post sentinels when they eat or sleep or engage in other hazardous undertakings, and these sentinels show a good deal of discrimination in distinguishing between animals that are friendly and those that are not. Beavers not only build lodges to live in, but also construct dams to keep the water in which the villages are located at a certain height. The outlet of these dams is carefully regulated, being regularly lessened and enlarged to suit the supply of water in the stream. The trees used by the beavers in their enterprises are felled by them along the margins of the stream, and floated to the place where they are used. In old communities, where the supply of timber near the stream has been exhausted, artificial canals are cut by these indomitable engineers for use in the transportation of their materials. These excavations are made at a great cost of labour and for the deliberate purpose of enabling the builders to accomplish that which they could not accomplish in any other way. ‘In executing this purpose,’ says Romanes, ‘there is sometimes displayed a depth of engineering forethought over details of structure required by the circumstances of special localities which is even more astonishing than the execution of the general idea’.[6] When, for instance, a canal has been carried so far from the original water-supply that, owing to the rising ground, it cannot be continued without a very great expenditure of effort in digging, a second dam is built higher up-stream, and with water drawn from this the canal is continued on at a higher level. Sometimes a third dam is built above the second, and the canal again continued at a still higher level before the valuable timber of the higher grounds is reached. These enterprising rodents also carve sometimes enormous channels across the necks of land formed by winding rivers, to serve as cut-offs in travel and transportation. And yet all of these things—all of the intelligence, feeling, and