In the Medicine Bow Mountains one December day, I came upon a beaver house that was surrounded by a pack of wolves. These beasts were trying to break into the house. Apparently an early autumn snow had blanketed the house and thus prevented its walls from freezing. The soft condition of the walls, along with the extreme hunger of the wolves, led to this assault. Two of these animals were near the top of the house clawing away at a rapid rate. Now and then one of the sticks or poles in the house-wall was encountered, and at this the wolf would bite and tear furiously. Occasionally one of the wolves caught a resisting stick in his teeth, and, leaning back, shook his head, endeavoring with all his might to tear it out. A number of wolves lay about expectant; a few sat up eagerly on haunches, while others moved about snarling, driving the others off a few yards, to be in turn driven off themselves. Shortly before they discovered me, there was a fierce fight on top of the house, in which several mixed. Even though they had broken into the house, it would have availed them nothing, for in this, as in all old colonies, there were safety tunnels from the house which extended beneath the pond to points on shore. In these tunnels the beaver find safety, if by any means the house is ruined. Although carnivorous animals are fond of beaver flesh, they rarely take the useless trouble of digging into a house. Occasionally a wolverine or a bear may dig into a thin-walled house or one not frozen, then, after breaking in, lie in wait, and endeavor to make a capture while the beaver are repairing the hole. Beaver are more secure from enemies during the winter than at any other time. It is while felling a tree far from the water or while following a shallow stream that most beaver are captured by their enemies. Many a time in winter I have made a pleasant visit to a beaver colony. One day, a few hours after a heavy snowfall, I came out of a dark forest and stood for a time on the edge of the snow-covered pond. Around were the firs and spruces of the forest, moveless as statues and each a pointed cone of snow. Around the small snowy plain of the pond, the drooping snow-entangled willows held their heads together in contented and thoughtful silence. Everything was serene. [Illustration: HOUSE, FOOD-PILE, POND, AND DAM IN WINTER] A clean fox track led from the woods in a straight line across the snowy surface of the pond to the house, which stood near the centre of this smooth white opening. The tracks encircled the house and ascended to the top of it, where the record imprinted in the snow told that here he watchfully rested. Descending, he had sniffed at the bushy tips of the winter food-pile that thrust up through the ice, then crossed the dam to plunge into the snowy tangle of willows.