The Earth's habitats range from the icy polar regions, where temperatures never rise above the freezing point, to bone-dry deserts where rain never falls. Some of these habitats are kinder than others.

Yet even the harshest environments have something to offer-and if there is any benefit to be had, an animal will learn how to take advantage of it. From the biggest to the smallest, these animals make up the tapestry of life we see around us.