So they turned into the north, not knowing that nature had already schemed that they four—­the dog, wolf, otter and beaver—­should soon be engaged in one of those merciless struggles of the wild which keep animal life down to the survival of the fittest, and whose tragic histories are kept secret under the stars and the moon and the winds that tell no tales.

For many years no man had come into this valley between the two ridges to molest the beaver.  If a Sarcee trapper had followed down the nameless creek and had caught the patriarch and chief of the colony, he would at once have judged him to be very old and his Indian tongue would have given him a name.  He would have called him Broken Tooth, because one of the four long teeth with which he felled trees and built dams was broken off.  Six years before Broken Tooth had led a few beavers of his own age down the stream, and they had built their first small dam and their first lodge.  The following April Broken Tooth’s mate had four little baby beavers, and each of the other mothers in the colony increased the population by two or three or four.  At the end of the fourth year this first generation of children, had they followed the usual law of nature, would have mated and left the colony to build a dam and lodges of their own.  They mated, but did not emigrate.

The next year the second generation of children, now four years old, mated but did not leave, so that in this early summer of the sixth year the colony was very much like a great city that had been long besieged by an enemy.  It numbered fifteen lodges and over a hundred beavers, not counting the fourth babies which had been born during March and April.  The dam had been lengthened until it was fully two hundred yards in length.  Water had been made to flood large areas of birch and poplar and tangled swamps of tender willow and elder.  Even with this food was growing scarce and the lodges were overcrowded.  This was because beavers are almost human in their love for home.  Broken Tooth’s lodge was fully nine feet long by seven wide inside, and there were now living in it children and grandchildren to the number of twenty-seven.  For this reason Broken Tooth was preparing to break the precedent of his tribe.  When Kazan and Gray Wolf sniffed carelessly at the strong scents of the beaver city, Broken Tooth was marshaling his family, and two of his sons and their families, for the exodus.

As yet Broken Tooth was the recognized leader in the colony.  No other beaver had grown to his size and strength.  His thick body was fully three feet long.  He weighed at least sixty pounds.  His tail was fourteen inches in length and five in width, and on a still night he could strike the water a blow that could be heard a quarter of a mile away.  His webbed hindfeet were twice as large as his mate’s and he was easily the swiftest swimmer in the colony.