Florence Hofer, age 11, of Raymond, Alberta, Canada., for her question¬
Why do brown rabbits turn white in winter?
Life among the mammals is a daily struggle for survival. The hunters must sneak up on their prey; the hunted must be able to avoid detection. Nature gives them ail a fair chance by clothing them in colors that blend in with their backgrounds. Even the gaudy zebra is hard to spot among the vivid streaks of sunlight and shadow on his grassy Africa plains. The brown rabbit who changes to winter white plays a role in this continual struggle for survival.
Most bunnies wear the same furry color schemes all year long. Their brownish grey tones match the earth and the shadowy, low growing foliage. When they crouch quietly in their natural surroundings, you may pass right by without seeing them. Even a hungry, sharp eyed coyote often fails to see them because their earthy colors blend in with their earthy backgrounds. This clever scheme of protective coloring gives a hunted rabbit a chance to hide from the hunter. But fair is fair. The hungry fox also wears colors to match his background which gives him a chance to sneak up on his dinner.
A few wild members of the bunny clan change their color schemes twice every year. In summer they wear brownish greys and for winter they change to outfits of snowy white. These turncoats happen to be bares, long legged leapers who live out in the open where winter snows blanket the scenery.
In summer the Arctic bare wears drab brown that matches the mottled browns of his native tundra. When winter covers his world with snow he sheds his summer coat and grows a thicker one of fluffy white. The prairie bare, alias the white tailed jack rabbit, lives in the Rockies and on the far northern plains. He also changes color with the seasons.
The most charming changeable bunny is the varying hare, alias the snowshoe rabbit. In summer he wears a reddish brown coat with a white vest. This color scheme blends with the thickets in his favorite woods. With the first snowfall, he begins to molt. Patches of brown are replaced with tufts of white and for a week or so he looks like a pinto. This patchwork is very noticeable and this is a risky time of his life. But when the change is complete, he has a thicker warm coat with tufted snowshoes on his feet. And his coat matches the winter scene. Over the snow he bounds like a flying white cloud and even a clever fox finds it hard to see which way he went.
Protective coloring is part of the story of natural selection. Nature selects the most suitable group of plants and animals to share this or that environment. The misfits are weeded out because they fail to cope with their surroundings. Those that survive have suitable features which are inherited by their children.