Hot deserts are found near the tropics of Cancer and Capricorn. The largest hot desert is the Sahara in Africa which spans the whole width of the continent.

Hot deserts have an extreme climate and challenging environment. There is very little biodiversity in hot deserts because of the harsh climate. Few species are specialised enough to survive there. Plants and animals which do survive there have adapted to difficult conditions.The biotic or living components and the abiotic or non-living components of the hot desert rely on one another - a change in one will lead to a change in the other.

The Sahara desert

Climate

• The climate is very hot. Summer day time temperatures can exceed 40°C. However, at night the temperature can drop below 0°C.
• The climate is very dry with less than 250 mm of rainfall a year.
• Hot deserts have two distinct seasons: summer, when the temperature ranges between 35-40°C, and winter, when the temperature ranges between 20-30°C.

Soil

• Desert soils are thin, sandy, rocky and generally grey in colour.
• Desert soils are very dry. When it does rain they soak up the water very quickly.
• The surface of the soil may appear crusty. This is due to the lack of rainfall. As it is so hot water is drawn up to the surface of the soil by evaporation. As the water evaporates, salts are left behind on the surface of the soil.

Plants and animals

Hot deserts have distinct characteristics that allow certain species to thrive in such an extreme environment. Plants and animals have developed adaptations which allow them to survive in hot and dry conditions.