Barren Ground Caribou roam the boreal forests and tundra regions of North America in much the same manner as wildebeests in Africa, in giant herds constantly on the move. About two million wildebeests encircle the giant Serengeti Plains and Mara ecosystem while somewhat fewer caribou, perhaps 1.5 million, make their rounds in America's far north. These beasts are postulated by some biologists to possess a "wandering gene," an instinct to move. Indeed they seldom seem still. Others insist it is the sparcity and low energy of food in their environment that "fuels" this fretful motion, so necessary to prevent overgrazing. And then there are the insects, a ferocious summer assault that terrorizes the caribou, causing them to fidget and flee in a futile attempt to escape. Only the return of cool in the fall will afford them the relief they seek.

Caribou numbers are slowly declining, mostly from human impact, but the herds are closely managed in America so there is little concern for a crash. The long term threats to caribou are loss of habitat from human encroachment and climate change. Disease epidemics take only a cyclic toll and are today fairly predictable.