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EXTREME HABITATS
Deserts
Deserts are mainly hot places with very little rainfall. Very few plants and animals can survive such difficult conditions.
Deserts are places where the rainfall is small and very unreliable. Most deserts are hot and sunny, so coping with drought is the main problem for any living thing in a desert (picture ).
Plants with a short life
Plants are adapted in two ways. One group are annuals, whose seeds lie in the desert soil until rain comes. Then, they race to germinate, grow, flower and set seed before the ground dries out. This may all happen in just a few weeks.
Plants that grow slowly
The other group of plants are perennials. Between rainfalls they simply stop growing.
Some desert perennials have deep tap roots to find water, even when it has seeped deep underground. To prevent losing water, they have small, waxy leaves with few pores.
Others, such as the cactus, store water in fleshy stems that can swell with water. They have no leaves at all, their green stems make all the food they need.
Animals in the desert
Animals, too, face the problems of getting water, avoiding the heat and finding food. Like mountains, deserts provide little food and so few animals can live there. Those that do each need a large territory if they are to find enough to eat.
Many desert animals burrow into the sand, or shelter in the shade, during the heat of the day, and only come out after dark. At night, the temperature falls sharply and dew is quite common. Many animals get all the moisture they need from the late-night dew.
Camels are one of the few desert animals that move about during the day. Camels can survive when they have lost almost a third of their body water. This is more than twice as much as most animals can lose. When they do find water, camels can drink a fifth of their body weight in ten minutes.
The hump of the camel is where it stores fat. This fat allows it to survive, even if it cannot find food for weeks. Camels also have thick fur to protect them from the heat, and pad-like hooves to make it possible to travel across soft sand.
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