Now if all animals that prey upon others were guided by the eye alone, there would be much more in the theory than there is. But none of the predaceous four-footed beasts depend entirely upon the eye. The cat tribe does to a certain extent, but these creatures stalk or waylay moving game, and the color does not count. A white hare will evidently fall a prey to a lynx or a cougar in our winter woods as easily as a brown rabbit; and will not a desertcolored animal fall a prey to a lion or a tiger just as readily as it would if it were white or black? Then the most destructive tribes of all, the wolves, the foxes, the minks, the weasels, the skunks, the coons, and the like, depend entirely upon scent. The eye plays a very insignificant part in their hunting, hence again the question of color is eliminated. Birds of prey depend upon the eye, but they are also protectively colored, and their eyes are so preternaturally sharp that no disguise of assimilative tints is of any avail against them. If both the hunted and its hunter are concealed by their neutral tints, of what advantage is it to either? If the brown bird is hidden from the brown hawk, and vice versa, then are they on an equal footing in this respect, and the victory is to the sharpest-eyed. If, as is doubtless the case, the eye of the hawk sharpens as the problem of his existence becomes more difficult, then is the game even, and the quarry has no advantage — the protective color does not protect. Why should the owl, which hunts by night, be colored like the hawk that hunts by day? If the owl were red, or blue, or green, or black, or white, would it not stand just as good a chance of obtaining a subsistence? Its silent flight, its keenness of vision, and the general obscurity are the main matters. At night color is almost neutralized. Would not the lynx and the bobcat fare just as well if they were of the hue of the sable or the mink? Are their neutral grays or browns any advantage to them? The gray fox is more protectively colored than the red; is he therefore more abundant? Far from it; just the reverse is true. The same remark applies to the red and the gray squirrels. The northern hare, which changes to white in winter, would seem to have an advantage over the little gray rabbit, which is as conspicuous upon the snow as a brown leaf, and yet such does not seem to be the case. It is true that the rabbit often passes the day in holes and beneath rocks, and the hare does not; but it is only at night that the natural enemies of each foxes, minks, weasels, wildcats, owls are abroad. It is thought by Wallace and others that the skunk is strikingly marked as a danger signal, its contrast of black and white warning all creatures to pass by on the other side. But the magpie is marked in much the same way, as is also our bobolink, which, in some localities, is called "the skunk-bird," and neither of these birds has any such reason to advertise itself as has the skunk. Then here is the porcupine, with its panoply of spears, as protectively colored as the coon or the woodchuck, why does not it have warning colors also? The enemy that attacks it fares much worse than in the case of its black and white neighbor. The ptarmigan is often cited as a good illustration of the value of protective coloration, — white in winter, particolored in spring, and brown in summer, always in color blending with its environment. But the Arctic fox would not be baffled by its color; it goes by scent; and the great snowy owl would probably see it in the open at any time of year. On islands in Bering Sea we saw the Arctic snowbird in midsummer, white as a snowflake, and visible afar. Our northern grouse carry their gray and brown tints through our winters, and do not appear to suffer unduly from their telltale plumage. If the cold were as severe as it is farther north, doubtless they, too, would don white coats, for the extreme cold seems to play an important part in this matter, this and the long Arctic nights. Sir John Ross protected a Hudson's Bay lemming from the low temperature by keeping it in his cabin, and the animal retained its summer coat; but when he exposed it to a temperature of thirty degrees below - zero, it began to change to white in a single night, and at the end of a week was almost entirely so. It is said that in Siberia domestic cattle and horses become lighter-colored in the winter, and Darwin says he has known brown ponies in England to become white during the same season. Only one of our weasels, the ermine, becomes white in winter; the others keep their brown coats through the year. Is this adaptive color any advantage to the ermine? and are the other weasels handicapped by their brown tints? The marten, the sable, and the fisher do not turn white in the cold season, nor the musk ox, nor the reindeer. The latter animals are gregarious, and the social spirit seems to oppose local color. Apart from the intense cold, the long Arctic nights no doubt have much to do with the white of Arctic animals. "Absence of light leads to diminution or even total abolition of pigmentation, while its presence leads to an increase in some degree proportionate to the intensity of the light."1 When the variable northern hare is removed to a milder climate, in the course of a few years it ceases to turn white in winter. The more local an animal is, the more does it incline to take on the colors of its surroundings, as may be seen in the case of the toads, the frogs, the snakes, and many insects. It seems reasonable 1 Vernon on Variation in Animals and Plants. that the influence of the environment should be more potent in such cases. The grasshoppers in the fields are of all shades of green and brown and gray, but is it probable that these tints ever hide them from their natural enemies - the sharp-eyed birds and fowls? A grasshopper gives itself away when it hops, and it always hops. On the seacoast I noticed that the grasshoppers were gray like the sands. What fed upon them, if anything, I could not find out, but their incessant hopping showed how little they sought concealment. The nocturnal enemies of grasshoppers, such as coons and skunks, are probably not baffled at all by their assimilative colors. Our wood-frog (Rana sylvatica) is found throughout the summer on the dry leaves in the woods, and it is red like them. When it buries itself in the leaf mould in the fall for its winter sleep, it turns dark like the color of the element in which it is buried. Can this last change be for protection also? No enemy sees it or disturbs it in that position, and yet it is as "protectively" colored as in summer. This is the stamp of the environment again. The toad is of the color of the ground where he fumbles along in the twilight or squats by day, and yet, I fancy, his enemy the snake finds him out without difficulty. He is of the color of the earth because he is of the earth earthy, and the bullfrog is of the color of his element, but there are the - |