Dolphins rely heavily on sound for communication and navigation. Their ears allow dolphins to use echolocation to find prey and navigate underwater. While dolphins have pectoral fins and a dorsal fin, their highly developed hearing makes their ears the most important body part. Dolphins are intelligent social animals that live in pods and communicate through clicks, whistles and other sounds. They can sleep resting half of their brain at a time, allowing them to sleep while still surface breathing and aware of their surroundings.