Following the afternoon when Gray Wolf and Kazan struck into the north came the clear still night when Broken Tooth climbed to the top of the dam, shook himself, and looked down to see that his army was behind him.  The starlit water of the big pond rippled and flashed with the movement of many bodies.  A few of the older beavers clambered up after Broken Tooth and the old patriarch plunged down into the narrow stream on the other side of the dam.  Now the shining silken bodies of the emigrants followed him in the starlight.  In ones and twos and threes they climbed over the dam and with them went a dozen children born three months before.  Easily and swiftly they began the journey down-stream, the youngsters swimming furiously to keep up with their parents.  In all they numbered forty.  Broken Tooth swam well in the lead, with his older workers and battlers behind him.  In the rear followed mothers and children.

All of that night the journey continued.  The otter, their deadliest enemy—­deadlier even than man—­hid himself in a thick clump of willows as they passed.  Nature, which sometimes sees beyond the vision of man, had made him the enemy of these creatures that were passing his hiding-place in the night.  A fish-feeder, he was born to be a conserver as well as a destroyer of the creatures on which he fed.  Perhaps nature told him that too many beaver dams stopped the run of spawning fish and that where there were many beavers there were always few fish.  Maybe he reasoned as to why fish-hunting was poor and he went hungry.  So, unable to cope singly with whole tribes of his enemies, he worked to destroy their dams.  How this, in turn, destroyed the beavers will be seen in the feud in which nature had already schemed that he should play a part with Kazan and Gray Wolf.

A dozen times during this night Broken Tooth halted to investigate the food supplies along the banks.  But in the two or three places where he found plenty of the bark on which they lived it would have been difficult to have constructed a dam.  His wonderful engineering instincts rose even above food instincts.  And when each time he moved onward, no beaver questioned his judgment by remaining behind.  In the early dawn they crossed the burn and came to the edge of the swamp domain of Kazan and Gray Wolf.  By right of discovery and possession that swamp belonged to the dog and the wolf.  In every part of it they had left their mark of ownership.  But Broken Tooth was a creature of the water and the scent of his tribe was not keen.  He led on, traveling more slowly when they entered the timber.  Just below the windfall home of Kazan and Gray Wolf he halted, and clambering ashore balanced himself upright on his webbed hindfeet and broad four-pound tail.  Here he had found ideal conditions.  A dam could be constructed easily across the narrow stream, and the water could be made to flood a big supply of poplar, birch, willow and alder.  Also the place was sheltered