merely their heads into holes for their prey, go boldly under ground and attack such prey as hares and marmots, or fasten upon fowls much larger than they themselves. From all such prey their foreheads have nothing to gain by being white, since in the hole all is dark, and in the case of these large victims attacked above ground, the attacker, if it be a weasel, is looked down at, not seen against the sky, while the martens,
| Fig. 12 shows the animal's white top performing its perhaps cardinal function, viz., that of effacing his top contour against the sky to the eyes of inhabitants of the turf. |
| This is the only function of the skunk's white top that is practically unceasing as long as the animal is above ground. We have already seen that his white and black cause each other, especially at night, to fade from sight at a short distance, and even at a near view, confuse themselves with forest details. But the obliterating power of night itself largely suffices to render all devices for concealment unnecessary. The great development of the ears of nocturnal animals attests their difficulty in seeing at this time. On the other hand, the night is scarcely ever so dark but that a solid form within a foot of one's eye would show dark against the sky or the light parts of the forest ceiling, and surely this must be the reason why skunks and the other grubbers of small surface life wear this wonderful counterfeit of sky on their foreheads. By its aid, they must constantly come close to many kinds of small surface-life on which they so largely feed, which would evade them if they could see them. This must be especially obvious to any one who has often tried in vain to creep within catching-distance of grass-hoppers. A single night's out-of-door experimenting will convince students of the importance of the white top to such an animal as a skunk. |
arboreal, acrobatic, swift and bloodthirsty, catch doubtless much after the bold manner of the small weasels, and obviously would not seem to have so much use for concealment from any particular viewpoint. The pine marten, however, is enough light-foreheaded to save his head from too much silhouetting in his above-ground forest operations against small terrestrial life.
In tall grass, to catch small terrestrial prey like mice, cats creep low, and fling themselves high in air, dropping flat outspread upon the dazed victim. Foxes vary this by coming down head-first upon it. In neither case would top-white help them—and they haven't it.
