Deserts cover about one third of the Earth's land area. The desert is a harsh environment with very little rainfall and extreme temperatures. Desert plant life is not abundant; neither is animal life.

Some deserts get both very hot (during the day) and very cold (during the night, temperatures can drop well below freezing). Some deserts, however, are always cold (for example, the Gobi Desert in Asia, and the desert on the continent of Antarctica).

Different animals live in the different types of deserts. Animals that live in the desert have adaptations to cope with the lack of water, the extreme temperatures, and the shortage of food. To avoid daytime heat, many desert animals are nocturnal; they burrow beneath the surface or hide in the shade during the day, emerging at night to eat. Many desert animals do not have to drink at all; they get all the water they need from their food. Most desert animals are small.