The bat’s echolocation system Read the text and answer the questions.
M
ost bats fly at night, catching insects.Though they are nocturnal creatures, many can’t see too well in the dark as their eyes are small and hidden by fur. As they fly, bats continually send out sounds, mostly too high for human ears. These high-pitched squeaks can only be ‘heard’ by the scientific instruments used by people studying the tiny mammals.
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Some bats make the sounds through their mouth and other bats through their nose.The sound waves travel through the air and hit a flying insect or perhaps a tree branch.The sounds then bounce back to the bat’s large, sensitive ears, just as an echo bounces back to our ears. After judging the time between echoes, a bat then uses its welldeveloped brain to work out exactly where the insect or tree branch is. It can also tell how quickly the insect is moving and in which direction! This method of catching prey is called ‘echolocation’ and a bat using it can devour hundreds of mosquitoes and other insect pests each night! In experiments many years ago, scientists found bats could still hunt insects when their eyes were covered, but when their ears were covered they couldn’t hear the echoes.
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5. Which parts of their body do bats use to make sounds?
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2. How are bats useful to us?
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1. Which word tells us bats come out at night?
6. There is a saying: ‘As blind as a bat’. Are bats blind?
o c . 3. How can scientists listen to the c e her 7. s r sounds bats make? Why o can’t we hear the sounds t s r upebats make?
4. What does a bat use to locate where an insect is?
8. Find words in the text for: concealed, bough, rapidly, eat, constantly.
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