can elephants hear better than dogs?

Well, elephants can definitely hear lower-register frequencies better than dogs. In fact, elephants often "hear" each other through their feet. Their feet are highly sensitive to low noises that humans and many other animals can't even hear. Remember though, that noise is just vibration.

Generally, "elephants hear and respond to each other's loud calls from distances as great as four kilometres away"(Payne P.121). This under normal conditions would mean elephants can communicate and hear a message within a fifty+ square kilometres range.

Dogs hear well too.

http://elephant.elehost.com/About_Elephants/Senses...

Yes