Desert animals have evolved ways to help them keep cool and use less water. Camels can go for weeks without water, and their nostrils and eyelashes can form a barrier against sand.

In existing deserts, some species are in peril because of climate change. Global warming threatens to change the ecology of deserts: Higher temperatures may produce more wildfires that alter desert landscapes by eliminating slow-growing trees and shrubs and replacing them with fast-growing grasses.

FAR FROM BEING barren wastelands, deserts are biologically rich habitats with a vast array of animals and plants that have adapted to the harsh conditions there.