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Bats and a lizard walkway

الأسبوع 9 · المحور الأول، الوحدة الأولى: مشروع الوحدة «التواصل بين الخفافيش» والمشروع البيني «حماية الحياة البرية» · 3 دروس
1

Bats: echoes in the dark

Discovery Education Science P4: Term 1, Unit 1, pp. 100–115
GoalExplain how bats use echoes to find their way and catch insects, and name their adaptations.
New words
echolocation · finding things by making sounds and listening to the echoesroost · to rest in a safe place, such as a cavecall · a sound that an animal makes to send a message
Explanation

Bats are mammals, not birds. They are not blind, and they are not scary. Many bats eat insects, including mosquitoes, and some bats pollinate flowers or spread the seeds of fruits. Insect-eating bats find their way in the dark by echolocation. A bat makes very high sounds, many too high for people to hear. The sounds hit things such as a wall or a moth and bounce back as echoes. The bat listens with its big ears. A quick echo means the object is close, and a later echo means it is farther away. The bat’s brain works out the shape and place, and the bat turns to catch the insect. Bats also make different calls for different messages, such as a call between a mother and her pup. Bat adaptations include wings of skin stretched over long finger bones, big ears, and claws for hanging upside down in a cave to rest during the day.

Worked examples
A bat flies out of a cave at dusk. It clicks, the echo returns from a moth, and the bat turns toward it. Echolocation helps it hunt in the dark.
AdaptationKind
wings of skinstructural
big earsstructural
hunting at nightbehavioural
resting in cavesbehavioural
making echolocation soundsbehavioural
Mariam says a bat’s hanging upside down is a behavioural adaptation. Marwan says the claws are a structural one. Both are right: the claws are a body part and hanging is a behaviour that uses them.
batfruitnew plant
Not all bats eat insects. Some fruit bats roost in caves and fly out at night to eat fruit. When they drop the seeds, new plants can grow. Bats are useful to people and plants.
Class activity

Bat diagram. On a big piece of paper draw a bat, a moth and arrows for the sound going out and the echo coming back. Write three questions about bats and find the answers in this lesson. Then add one question to ask a grown-up. Show the diagram to someone at home and explain it using the words echo and echolocation.

Practice
1
Are bats birds? Are they blind?
2
A bat hears a quick echo. Is the object near or far?
3
Is the bat’s call between a mother and her pup an example of what?
4
Name one way bats are useful.