Why do you think that sound is an important means of communication between whales?

Whales sounds travel through water more than four times as fast as sound travels through air, and those sounds can travel great distances. Whales use 'songs' that may last as long as thirty minutes to attract mates. Other shorter whale songs are used as feeding calls, to attract other whales to get ready for a hunt where they form a group to catch large schools of fish. Other whale communications consist of what sound to humans like moans, grunts, thumps, chirps, and whistles. Scientists are studying whale sounds to learn more about how these animals communicate with each other.