Deserts are the driest place on earth. Very few rainfalls in deserts and few plants can grow. Scientists usually say that in the area in the desert if an average of fewer than 250 millimeters of rain falls each year. About one-fifth of the land on earth is Deserts.
Kind of deserts
There are two kinds of desert.
- Cold desert: These deserts are dry and cold. they are found in the Arctic and Antarctic regions around the North and South pole. The ground is covered with ice and snow for all or most of the year.
- Hot desert: These deserts are hot and dry during the day. although they can be very cold at night. Some hot deserts are sandy. The wind blows the sand into hills called dunes. However, in most hot deserts, the wind has blown the sand away, leaving pebbles or even bare rocks. Sometimes there are mountains and steep rocky slopes. Some of the mountains have been carved into interesting shapes by the wind.
The world’s largest hot desert is the Sahara Desert in North Africa.
Not many plants can survive in the desert. Those that do live there have special adaptations that allow them to survive the dry conditions. Some desert plants have very long roots to reach water underground. The roots of the mesquite bush of North America may go down 50 meter to reach water. A cactus stores water in its thick stems.
Few animals live in the desert. Many of those that do get the water they to need from their food. Most of them sleep during the day and only come out at night when it is cooler.
The best-known desert animal is the camel. A camel can go for a long time without water. It can lose about one third of the weight of its body and still live. Then, when the camel does find water, it can drink 115 liters or more in a few minutes.