Because their large ears act like ear-trumpets to collect the waves of sound, and thus increase their faculty of hearing.
How can these animals still farther increase their sense of hearing?
By being able to turn their ears, just as we do the ear-trumpet, in the direction whence the sound comes.
What are speaking-tubes?
They are metal pipes extending from one part of a building to another part.
Of what use are speaking-tubes?
They are used to convey the voice to the more distant parts of a building.
Do they require loud talking?
No; even a whisper has been heard through a metal pipe over three thousand feet long.