The New Childrens Encyclopedia

62

Deserts

We think of deserts as being hot, but some of them

are very cold. What deserts ARE is dry. Any place

that gets less than 10 in (25 cm) of rain or snow

per year (such as the Antarctic ice sheet) is a desert.

TELL ME MORE...

The Saguaro cactus is one of the

tallest in the world—it can grow

as high as 40 ft (12 m) and live

for up to 200 years. Only found

in Arizona, California, and

northern Mexico, it needs more

water than some cacti, but it’s

fairly tolerant of frost.

CACTIFIT FOR

PURPOSE

The “body” of a cactus plant

is actually a swollen, water-

storing stem. The “prickles”

are a kind of leaf that

allows very little water to

evaporate. In some desert

plants, it’s the leaves that

swell and store water—

these are called succulents.

Golden

barrel cactus

WARM DESERTS

The thing about hot deserts is that they’re hot all the

time—cold deserts can be frosty in winter and

boiling in summer. There is not much moisture,

so there are very few clouds. At night, with

no cloud “blanket,” the temperature can

drop dramatically.

This is the

Sonoran Desert in

the southwestern

United States.

DESERT IN BLOOM

Once in a while, there is a rare and

precious shower of rain, and the desert

bursts into bloom. (See above, Anza-

Borrego State Park, California.) This is

because seeds lie dormant—sometimes for

years. When water falls, they germinate,

flower, and create new seeds.

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ENVIRONMENTAND ECOLOGY

(c) 2012 Dorling Kindersley. All Rights Reserved.(c) 2012 Dorling Kindersley. All Rights Reserved.