Deserts cover about one-fifth of the Earth's land surface and are typically found near the Tropics or in places like the southwest US, South America, Africa, Australia and the Middle East. Deserts receive less than 30cm of rain annually and have hot days and cold nights. Plants in deserts are scattered and adapted to store water, like cacti, while animals are nocturnal and burrow underground or are adapted to limited water intake. Some common desert plants and animals include various cacti, bushes, coyotes, kangaroo rats and tortoises.