bats are the only flying animals in the world急求整篇文章

Bats are the only flying mammals (哺乳动物) in the world.They can’t see very well.It was long believed and still is in many places,that all bats are blind."Blind as a bat" is often heard.Yet they have no trouble in flying on the darkest nights and finding their way around very well.How can bats fly and see at night?They fly by radar.
The bat’s radar system works the same way as the one that ships and planes use.As a bat flies through the air,it makes a sound that is too high for our ears to hear.If the sounds hit things,they come back.The bat’s ears receive the messages.In this way they are able to tell where the things are.Bats go out to look for food at night.In the daytime they hang in some dark places.Some people have the bats as bad animals.In fact,they are useful animals