These colonists had a hard winter. I visited them a number of times. Now and then snow covered the frozen pond, but usually the wind in sweeping down the open-stream avenue through the woods left the ice clear. One day, looking through the clear ice of the pond, I counted six beavers, but on most occasions I was able to see only one or two. The population of this colony probably numbered twelve or fifteen. The upper part of the area flooded by their pond had been a semi-swampy tract bearing thick growths of water-loving plants. The roots of sedge, bulbs of lilies, tubers of many plants, and long juicy roots of willow and alder were made use of by these beavers facing a food-shortage. I supposed it was only a question of time before they would be shut off by the thick ice from this root supply. But they dug a deep waterway--a canal about two feet wide and nearly as deep--from the house in the centre of the pond to the heart of the rooty area. Even after most of the pond was frozen to the bottom they had an open line of communication with the root supplies. Mutual aid is a factor in beaver life. I do not know how many days’ work this ditch required; but when one of the beavers in a colony work, all work. Since late summer these beavers had worked at one task after another; they had unitedly worked for the welfare of each member of the colony. With mutual aid beaver colonists achieve much in a short time. Their strong love for home, causing them to remain long in one place, and the peculiar work which this calls for, makes changes on earth sometimes enduring for centuries. But they had only commenced to dig out the roots on the bottom of the pond when the ever-thickening ice froze over this life-saving food supply. The water would have been deeper over this area but the beavers’ early hard luck had prevented their building the dam as high as it should have been. I do not know how they handled the food-shortage, whether or not they went on short rations. But no beaver had more than his portion, for beavers are coöperators, they work in common, and so long as the food supply lasts each has his share. I had glimpses of the beavers’ eager digging through the clear spots in the ice. They tore the root-filled section to pieces and devoured all that it contained. But not until the following summer, when the broken dam released the water, did I realize how deeply and completely the bottom of the pond had been stirred and ploughed. I have seen gardens uprooted by hogs, and mountain meadows dug to pieces by grizzly bears, but neither of them equalled this.