Deserts
Do you think of a desert as a hot,
dry place where sand stretches as far as you can see? The Sahara in North Africa
is like that, but most deserts are not. All deserts are dry, but some deserts
are very cold. Plants and animals live in most deserts. People have learned to
live in deserts all over the world.
Most deserts form because of air
movements over the planet. Masses of dry air create deserts. For example,
deserts can form where air currents go over mountains. Water gets squeezed out
of the air as it passes over the mountains, and a desert forms on the other side
of the mountains. Deserts can also form along some seacoasts where there are
currents of cold water. There are two main bands of desert areas, one north of
the equator and one south of the equator. The equator is an imaginary line that
goes around Earth’s middle.
| Desert | Location | square miles | square kilometers |
|---|---|---|---|
| Sahara | northern Africa | 3,500,000 | 9,060,000 |
| Gobi | Mongolia/northeastern China | 500,000 | 1,290,000 |
| Patagonian | Argentina | 260,000 | 670,000 |
| Rub al Khali | southern Arabian Peninsula | 250,000 | 650,000 |
| Great Sandy | northwestern Australia | 100,000 | 270,000 |
| Great Victoria | southwestern Australia | 130,000 | 350,000 |
| Chihuahuan | Mexico/southwestern United States | 140,000 | 360,000 |
| Takla Makan | northern China | 140,000 | 360,000 |
| Sonoran | Mexico/southwestern United States | 120,000 | 310,000 |
| *These area figures are estimates because the boundaries of deserts are not always clear. | |||
MAJOR DESERTS OF THE WORLD
The largest desert in the world is
the Sahara. It covers a land area as big as the United States. Huge waves of
sand called dunes cover most of the Sahara. The Sahara is very hot during the
day, but it cools off at night because sand does not hold heat well.
The Gobi Desert in Asia is the
largest cold desert. The Gobi covers parts of Mongolia and China. The Gobi gets
very cold in the winter, but it can be hot during the summer.
A large desert covers parts of the
southwestern United States and northern Mexico. There are also big desert areas
in the Middle East, Australia, and South America.
DESERT PLANTS
Deserts get very little rain, but
cactuses, trees, shrubs, and even wildflowers still manage to grow in some
desert areas. These plants have special features, or adaptations, that help them
get and store water. They have small leaves to keep water from escaping into the
air. Some desert plants have long roots that reach water deep underground. Other
plants, called succulents, can store water from a desert rainstorm in thick
roots, stems, and leaves. Some desert plants grow for only a few days. They
sprout after a rainfall. Then they die, and their seeds lie in the soil until
the next rain comes. The Sahara and deserts in the Middle East are so dry that
they have few plants.
DESERT ANIMALS
Many kinds of animals also live in
the desert. They include birds, insects, snakes, lizards, and some kinds of
mammals. Desert animals have adaptations that help them survive. In hot deserts,
centipedes, scorpions, and rattlesnakes burrow into the ground during the day to
stay cool. Some foxes and rabbits that live in the desert have large ears that
let body heat escape.
The camel is a large mammal with a
hump on its back that lives in the Sahara and Middle East deserts. Camels can go
for days without food or water. Camels use the fat in their hump for
energy.
PEOPLE OF THE DESERTS
Millions of people live in deserts
around the world. Some people mine copper or other metals in desert mines. Some
people work on desert farms. Shepherds in the Middle East go from place to place
looking for food and water for their animals.
People who live in deserts usually
live near a source of water. They live on the banks of rivers that flow through
deserts. They live on oases, places that have underground springs or wells.
Water is so important to life in the desert that it must be used sparingly and
be carefully protected.
People sometimes bring water to
deserts. They dig canals to bring in water from rivers. They use the water for
drinking and for growing crops. In the southwestern United States, people bring
water from the Colorado River into the desert for people to drink and to grow
crops.
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