Most of the world's deserts occur at low latitudes close to the equator, although there are high-latitude deserts as well. Both hot and cold deserts exist, and deserts occur on all seven continents.
Approximately one-fifth of the Earth is desert. Desert classifications include hot and dry, semiarid, coastal and cold. While most conceive of deserts as hot environments, a desert is any region of the world that receives less than 50 centimeters of rainfall every year.
Hot and dry deserts occur in North America, South America, Asia, Africa and Australia. Examples of this desert type are the Mojave Desert in North American and Africa's Sahara Desert. Fauna tends to be nocturnal to take advantage of cooler night-time temperatures.
North America, Europe and Asia contain semiarid deserts, which include the sagebrush habitats of North America. Spiny plants and jackrabbits are among the flora and fauna of semiarid deserts. Dew accumulation from cooler night temperatures actually exceeds annual rainfall in some locations.
The Atacama Desert of Chile is a famous coastal desert. There is no evidence of rainfall in some parts of the Atacama in recorded human history.
Antarctica, North America and Europe are home to the world's cold deserts. The average temperatures in parts of Antarctica are minus 20 degrees Celsius, with no rainfall.