A desert is an environment characterized by little available moisture for plant life due to imbalances between precipitation and evapotranspiration. Desert regions experience considerable rainfall variability, low atmospheric humidity, high daytime temperatures, and winds. Average annual precipitation usually ranges from almost zero to 400 millimeters, but some authorities consider 250 millimeters as the upper limit. The shortage of water determines which plants and animals can survive there, and they possess unique adaptations to thrive in dry conditions and make the most of brief wet periods. Desertification, or the expansion of desert environments, is a growing concern resulting from climatic variations and unsustainable human activities.

Where are deserts found in the world?

Deserts, defined as large, extremely dry areas with sparse vegetation, are a major ecosystem found worldwide, particularly in Africa and Australia. Most hot deserts lie on the western sides of continents near 30° N and 30° S latitude. Temperate deserts are usually in continental interiors or in the rain shadows of tall mountain ranges, while polar deserts are in ice-covered areas near the North and South Poles. Examples of deserts by continent: * Africa Sahara, Libyan, Kalahari, Namib * Asia Arabian, Gobi, Kyzylkum, Takla Makan, Karakum * Australia Great Victoria, Great Sandy, Gibson, Simpson * North America Great Basin, Chihuahuan, Sonoran, Mojave * South America Patagonian, Atacama

What kind of weather do deserts usually have?

Deserts are known for their shortage of moisture for plants because of imbalances between precipitation and evapotranspiration. This is made worse by variable rainfall, low humidity, high daytime temperatures, and winds. Most recognized deserts get less than 16 inches (400 mm) of rain annually. Some deserts get almost no rain, while others can get up to 24 inches (600 mm). Rainfall, when it occurs, can be very heavy but brief. Temperatures in hot deserts can be very high during the day, exceeding 104 °F (40 °C). The highest recorded temperature was 136.4 °F (58 °C) in Libya. Night temperatures can fall dramatically because of the lack of cloud cover. Temperate or cold deserts, found at higher latitudes, experience colder temperatures. These deserts are arid due to their remoteness from the coast or the presence of mountains.

What plants and animals live in deserts?

Deserts are home to a variety of plants and animals that have adapted to arid conditions. Desert plants, also known as xerophytes, include deep-rooted phreatophytes that tap into groundwater, as well as succulents that store water in their fleshy tissues. Examples of desert flora include sagebrush, saltbush, Joshua trees, cacti, and thorny shrubs like mesquite. Desert fauna includes reptiles, birds, rodents, and larger mammals. Many desert animals, such as the jerboa, are nocturnal, seeking shelter in cool burrows during the day. Some desert birds are nomadic, relocating to areas where rain has fallen to find food. Protective coloration is an important feature of desert life.

How do plants and animals survive in the harsh conditions of a desert?

Desert plants and animals have developed unique strategies to survive the harsh desert environment. Plants are typically xerophytes or phreatophytes . Xerophytes are plants adapted to arid conditions that prevent water loss by having thick, fleshy stems or leaves, waxy coatings, or the ability to drop leaves during dry periods. Phreatophytes are deep-rooted plants that rely on a permanent water supply and survive by tapping into groundwater. Desert animals often avoid the heat by staying in cool, humid burrows during the day and emerging at night to find food. To conserve water, desert animals have skin relatively impervious to water, and some can lower the temperature of exhaled air to reduce water loss during respiration. Also, protective coloration is an important feature of desert life.

What are some differences between hot deserts and cold deserts?

Hot and cold deserts differ primarily in temperature and location. Hot deserts are in subtropical regions, while cold deserts are in temperate areas at higher latitudes and elevations. Hot deserts experience high daytime temperatures, with maximums exceeding 104°F (40°C), whereas cold deserts have long, cold winters with average temperatures below freezing. Precipitation, mainly as snow or fog, is scant in cold deserts. Both experience low humidity and considerable rainfall variability. The Gobi Desert in China and Mongolia and the Great Basin Desert in the United States are examples of cold deserts, while the Sonoran and Chihuahuan Deserts in North America are hot deserts.

Desert

References & Edit History Related Topics

Images & Videos

Red sand dune with scattered dry grasses and small shrubs in the Simpson Desert, central Australia.

distribution of hot and temperate deserts

Tour the butte escarpments and vegetative landscape of Arizona desert terrain

Understand the concept of Hadley cells in explaining tropical rain forests and deserts

At a Glance

desert summary

Desert

ecosystem

Written by

Jeremy M.B. Smith

Fact-checked by

Britannica Editors

Last updated

Nov. 12, 2026 •History

Top Questions

What is a desert?
A desert is an environment characterized by little available moisture for plant life due to imbalances between precipitation and evapotranspiration. Desert regions experience considerable rainfall variability, low atmospheric humidity, high daytime temperatures, and winds.

Average annual precipitation usually ranges from almost zero to 400 millimeters, but some authorities consider 250 millimeters as the upper limit. The shortage of water determines which plants and animals can survive there, and they possess unique adaptations to thrive in dry conditions and make the most of brief wet periods.

Desertification, or the expansion of desert environments, is a growing concern resulting from climatic variations and unsustainable human activities.
4 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Where are deserts found in the world?
Deserts, defined as large, extremely dry areas with sparse vegetation, are a major ecosystem found worldwide, particularly in Africa and Australia. Most hot deserts lie on the western sides of continents near 30° N and 30° S latitude. Temperate deserts are usually in continental interiors or in the rain shadows of tall mountain ranges, while polar deserts are in ice-covered areas near the North and South Poles.

Examples of deserts by continent:
* Africa Sahara, Libyan, Kalahari, Namib
* Asia Arabian, Gobi, Kyzylkum, Takla Makan, Karakum
* Australia Great Victoria, Great Sandy, Gibson, Simpson
* North America Great Basin, Chihuahuan, Sonoran, Mojave
* South America Patagonian, Atacama
7 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What kind of weather do deserts usually have?
Deserts are known for their shortage of moisture for plants because of imbalances between precipitation and evapotranspiration. This is made worse by variable rainfall, low humidity, high daytime temperatures, and winds.

Most recognized deserts get less than 16 inches (400 mm) of rain annually. Some deserts get almost no rain, while others can get up to 24 inches (600 mm). Rainfall, when it occurs, can be very heavy but brief.

Temperatures in hot deserts can be very high during the day, exceeding 104 °F (40 °C). The highest recorded temperature was 136.4 °F (58 °C) in Libya. Night temperatures can fall dramatically because of the lack of cloud cover.

Temperate or cold deserts, found at higher latitudes, experience colder temperatures. These deserts are arid due to their remoteness from the coast or the presence of mountains.
3 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What plants and animals live in deserts?
Deserts are home to a variety of plants and animals that have adapted to arid conditions. Desert plants, also known as xerophytes, include deep-rooted phreatophytes that tap into groundwater, as well as succulents that store water in their fleshy tissues. Examples of desert flora include sagebrush, saltbush, Joshua trees, cacti, and thorny shrubs like mesquite.

Desert fauna includes reptiles, birds, rodents, and larger mammals. Many desert animals, such as the jerboa, are nocturnal, seeking shelter in cool burrows during the day. Some desert birds are nomadic, relocating to areas where rain has fallen to find food. Protective coloration is an important feature of desert life.
6 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How do plants and animals survive in the harsh conditions of a desert?
Desert plants and animals have developed unique strategies to survive the harsh desert environment. Plants are typically xerophytes or phreatophytes. Xerophytes are plants adapted to arid conditions that prevent water loss by having thick, fleshy stems or leaves, waxy coatings, or the ability to drop leaves during dry periods. Phreatophytes are deep-rooted plants that rely on a permanent water supply and survive by tapping into groundwater.

Desert animals often avoid the heat by staying in cool, humid burrows during the day and emerging at night to find food. To conserve water, desert animals have skin relatively impervious to water, and some can lower the temperature of exhaled air to reduce water loss during respiration. Also, protective coloration is an important feature of desert life.
6 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What are some differences between hot deserts and cold deserts?
Hot and cold deserts differ primarily in temperature and location. Hot deserts are in subtropical regions, while cold deserts are in temperate areas at higher latitudes and elevations.

Hot deserts experience high daytime temperatures, with maximums exceeding 104°F (40°C), whereas cold deserts have long, cold winters with average temperatures below freezing. Precipitation, mainly as snow or fog, is scant in cold deserts. Both experience low humidity and considerable rainfall variability.

The Gobi Desert in China and Mongolia and the Great Basin Desert in the United States are examples of cold deserts, while the Sonoran and Chihuahuan Deserts in North America are hot deserts.
4 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Desert, any large, extremely dry area of land with sparse vegetation. It is one of Earth’s major types of ecosystems, supporting a community of distinctive plants and animals specially adapted to the harsh environment. For a list of selected deserts of the world, see below.

Desert environments are so dry that they support only extremely sparse vegetation; trees are usually absent and, under normal climatic conditions, shrubs or herbaceous plants provide only very incomplete ground cover. Extreme aridity renders some deserts virtually devoid of plants; however, this barrenness is believed to be due in part to the effects of human disturbance, such as heavy grazing of cattle, on an already stressed environment.

According to some definitions, any environment that is almost completely free of plants is considered desert, including regions too cold to support vegetation—i.e., “frigid deserts.” Other definitions use the term to apply only to hot and temperate deserts, a restriction followed in this account.

Origin

The desert environments of the present are, in geologic terms, relatively recent in origin. They represent the most extreme result of the progressive cooling and consequent aridification of global climates during the Cenozoic Era (65.5 million years ago to the present), which also led to the development of savannas and scrublands in the less arid regions near the tropical and temperate margins of the developing deserts. It has been suggested that many typical modern desert plant families, particularly those with an Asian centre of diversity such as the chenopod and tamarisk families, first appeared in the Miocene (23 to 5.3 million years ago), evolving in the salty, drying environment of the disappearing Tethys Sea along what is now the Mediterranean–Central Asian axis.

Deserts also probably existed much earlier, during former periods of global arid climate in the lee of mountain ranges that sheltered them from rain or in the centre of extensive continental regions. However, this would have been primarily before the evolution of angiosperms (flowering plants, the group to which most present-day plants, including those of deserts, belong). Only a few primitive plants, which may have been part of the ancient desert vegetation, occur in present-day deserts. One example is the bizarre conifer relative welwitschia in the Namib Desert of southwestern Africa. Welwitschia has only two leaves, which are leathery, straplike organs that emanate from the middle of a massive, mainly subterranean woody stem. These leaves grow perpetually from their bases and erode progressively at their ends. This desert also harbours several other plants and animals peculiarly adapted to the arid environment, suggesting that it might have a longer continuous history of arid conditions than most other deserts.

Arabian Camel (Camelus dromedarius) in the Sahara Desert sand dunes. (pack animal; sand; Morocco; Africa; African desert; mammal; dromedary; drought)

Britannica Quiz

Quick Quiz: Deserts

Desert floras and faunas initially evolved from ancestors in moister habitats, an evolution that occurred independently on each continent. However, a significant degree of commonality exists among the plant families that dominate different desert vegetations. This is due in part to intrinsic physiologic characteristics in some widespread desert families that preadapt the plants to an arid environment; it also is a result of plant migration occurring through chance seed dispersal among desert regions.

Such migration was particularly easy between northern and southern desert regions in Africa and in the Americas during intervals of drier climate that have occurred in the past two million years. This migration is reflected in close floristic similarities currently observed in these places. For example, the creosote bush (Larrea tridentata), although now widespread and common in North American hot deserts, was probably a natural immigrant from South America as recently as the end of the last Ice Age about 11,700 years ago.

Explore Britannica Premium!

The trusted destination for professionals, college students, and lifelong learners.

Migration between discrete desert regions also has been relatively easier for those plants adapted to survival in saline soils because such conditions occur not only in deserts but also in coastal habitats. Coasts can therefore provide migration corridors for salt-tolerant plants, and in some cases the drifting of buoyant seeds in ocean currents can provide a transport mechanism between coasts. For example, it is thought that the saltbush or chenopod family of plants reached Australia in this way, initially colonizing coastal habitats and later spreading into the inland deserts.

Desert

Thank you for signing up!

Origin