Deserts are places on earth that are characterized by little vegetation
and rain. They are made up of sand or rocks and gravel. Deserts cover
about one-fifth of all the land in the world. Most deserts lie along the
Tropic of Cancer and Tropic of Capricorn, imaginary lines that lie north
and south of the equator.
Oases are parts of the desert where plants grow and water is almost always
available. An oasis is formed by a pool of water trapped between layers of
rock beneath the desert floor. The regular water in an oasis allows people
to settle in the desert and even grow crops.
Some deserts are named and nicknamed things like Death Valley, "the empty
quarter," and "the place from where there is no return" because of the
lack of water there.
The desert is the hottest biome on earth. However, the desert is also a
land of extremes. It can be over 100 degrees Farenheit during the day but
below 32 degrees at night. This change is because deserts are bare. There
is little protection to keep them from heating up in the sun and cooling
off when the sun disappears at night.
The amount of rainfall also varies. Though there is little rain in a
desert, when it does rain, it pours. Violent rainstorms can cause
flashfloods in the desert. After a storm, the desert may not see any rain
for weeks or months.
There are some plants that are able to survive in the desert. They may
have to go without fresh water for over a year! They also have to adjust
to very hot days and very cold nights.
Some plants have very long roots which grow in to the ground to reach
underground water sources. Some up as much water as they can during
the rain and save it in their stems and leaves. Some store the food and
water underground in thick roots.
Rain brings life to the desert. Shortly after a big storm, billions of
seeds come to life in the form of flowering plants. These plants are
called ephemerals. Eight weeks after a rain, the flowers are gone.
The cactus is the most well-known desert plant. This old man cactus has a
layer of hair that helps it to store water.
desert jack rabbit eats plants, such as the cactus. It is very
careful to avoid the prickly spines! Its ears pick up any sound of danger.
They also help keep the rabbit cool because heat can escape through the
tiny blood vessels that are found there.
There are hundreds of different animals that live in deserts. However,
most of them can only be found at dawn or dusk because that is when they
move around. For the rest of the day, animals bury themselves in the sand
or hide beneath rocks to keep cool. Animals that come out at night are
Animals in the desert eat plants and each other to survive. Many feed on
the roots, stems, leaves, and seeds of plants. These animals are then
eaten by bigger animals. Some animals get enough water from their food,
but others must travel to water holes.
Camels are the most well known desert animals. They are sometimes called
"the ship of the desert" because they can cross the desert better than any
other animal. Camels have bushy eyebrows and two rows of eyelashes to keep
the sand out of their eyes. Their nostrils can also be closed. The humps
on camels' backs do not hold water as commonly believed. Instead they
store fat reserves that can be broken down into food when crossing the
desert. The hump will shrink if a camel is starving.