No, they can't hear but they can feel vibrations. They can also produce their own vibrations when not happy with something. Amy used to hate it when my hair touched her - she would 'buzz' my hand. She even made a little noise once when she did it too!
No. But that doesn't mean that if you scream at the top of your lungs they aren't going to 'hear' anything haha. As previous members said, they have internal ears, I guess you could say.