In southern climates--in Louisiana, for instance--the swamps and rivers do not freeze over in winter. There the muskrat does not construct such houses as that described, but is contented all the year with his burrow in the banks. He can go forth freely and seek his food at all seasons. In the north it is different. There for months the rivers are frozen over with thick ice. The muskrat could only come out under the ice, or above it. If the latter, the entrance of his burrow would betray him, and men with their traps, and dogs, or other enemies, would easily get at him. Even if he had also a water entrance, by which he might escape upon the invasion of his burrow, he would drown for want of air. Although an amphibious animal, like the beaver and otter, he cannot live altogether under water, and must rise at intervals to take breath. The running stream in winter does not perhaps furnish him with his favourite food--the roots and stems of water-plants. These the swamp affords to his satisfaction; besides, it gives him security from the attacks of men and preying animals, as the wolverine and fisher. Moreover, his house in the swamp cannot be easily approached by the hunter--man--except when the ice becomes very thick and strong. Then, indeed, is the season of peril for the muskrat, but even then he has loopholes of escape. How cunningly this creature adapts itself to its geographical situation! In the extreme north--in the hyperborean regions of the Hudson's Bay Company--lakes, rivers, and even springs freeze up in winter. The shallow marshes become solid ice, congealed to their very bottoms. How is the muskrat to get under water there? Thus, then, he manages the matter:-- Upon deep lakes, as soon as the ice becomes strong enough to bear his weight, he makes a hole in it, and over this he constructs his dome-shaped habitation, bringing the materials up through the hole, from the bottom of the lake. The house thus formed sits prominently upon the ice. Its entrance is in the floor--the hole which has already been made--and thus is kept open during the whole season of frost, by the care and watchfulness of the inmates, and by their passing constantly out and in to seek their food--the water-plants of the lake. This peculiar construction of the muskrat's dwelling, with its water-passage, would afford all the means of escape from its ordinary enemies--the beasts of prey--and, perhaps, against these alone nature has instructed it to provide. But with all its cunning it is, of course, outwitted by the superior ingenuity of its enemy--man.