my observation as jet, All the small weasels that I have seen have proved on close inspection to be young ermines with thickly furred black-tipped tails; in the least weasel the tail is thinly covered with
short hair and without any black whatever. Late in the autumn or early in the winter the ermine changes from reddish-brown to white, sometimes slightly washed with greenish-yellow or cream color, and again as brilliantly white as anything in Nature or art; the end of the tail, however, remains intensely black, and at first thought might be supposed to make the animal conspicuous on the white background of snow, but in reality has just the opposite effect, Place an ermine on new-fallen snow in such a way that it casts no shadow, and you will find that the black point holds your eye in spite of yourself, and that at a little distance it is quite impossible to follow the outline of the weasel itself. Cover the tail with snow, and you can begin to make out the position of the rest of the animal, but as long as the tip of the tail is in sight you see that and that only. The ptarmigan and northern hare also retain some spot or point of dark color when they take on their winter dress, 
and these dark points undoubtedly serve the same purpose as in the case of the ermine. An old hunter, one of the closest observers of Nature I have ever known, once told me that female minks hibernated in winter in the same manner as bears, though it was his belief that, unlike the bears, they never brought forth their young at that season. At first I refused to take the slightest stock in what he said; the whole thing appeared so absurd and so utterly at variance with the teachings of those naturalists who have made the closest possible study of the habits
