That brings up the question--what is a silver fox? Strange as it may seem, neither scientist nor hunter can answer that question. Nor will study of all the park specimens in the world tell the secret, for the simple reason that only an Arctic climate can produce a silver fox; and parks are not established in the Arctics yet. It is quite plain that the prairie fox is in a class by himself. The uniformity of his size, his strength, his habits, his appearance, distinguish him from other foxes. It is quite plain that the little kit fox or swift is of a kind distinct from other foxes. His smallness, the shape of his bones, the cast of his face, the trick of sitting rather than lying, that wonderful big bushy soft tail of which a peacock might be vain--all differentiate him from other foxes. The same may be said of the Arctic fox with a pelt that is more like white wool than hairs of fur. He is much smaller than the red. His tail is bushier and larger than the swift, and like all Arctic creatures, he has the soles of his feet heavily furred. All this is plain and simple classification. But how about Mr. Blue Fox of the same size and habit as the white Arctic? Is he the Arctic fox in summer clothing? Yes, say some trappers; and they show their pelts of an Arctic fox taken in summer of a rusty white. But no, vow other trappers--that is impossible, for here are blue fox-skins captured in the depths of midwinter with not a white hair among them. Look closely at the skins. The ears of one blue fox are long, perfect, unbitten by frost or foe--he was a young fellow; and he is blue. Here is another with ears almost worn to stubs by fights and many winters' frosts--he is an old fellow; and he, too, is blue. Well, then, the blue fox may sometimes be the white Arctic fox in summer dress; but the blue fox who is blue all the year round, varying only in the shades of blue with the seasons, is certainly not the white Arctic fox.