no
they can hear better out of the water
sonar
as long as they want until they need to spout the water
Dolphins hear with their ears BUT when it comes to their sonar they 'hear' with their jaw.
dolphins hate getting bitten by sharks
sound can be produced in any medium - air, water and solids too, but most of the sounds we hear are through air. Animals like dolphins produce sound in water and hear it there.
dolpins hear through an echo
Because some sounds travel very well through water.
dolphin sleep in ocean and in hear share
nothing
The radio waves are quickly absorbed by water, specially salted water. So instead, sonar waves are used. This is what the dolphins use to communicate underwater. In documentaries on TV, you can hear a fast ticking noise when they're filming dolphins.
They find their way by sending out high-pitched sounds (at a level too high for humans to hear). The dolphins then listen for the returning echoes as they bounce off objects. This is called "echolocation", and it lets dolphins know what is around them.