Why do whales sing underwater?

Sound travels much farther in water than in air, so whales can communicate over tens or even hundreds of kilometres. Baleen whales such as humpbacks produce complex songs, while blue whales and fin whales make very low-frequency calls that can carry especially far. These sounds help whales find mates, coordinate movement, and maintain social contact. Humpback whale songs were first recorded and studied in detail in the 1960s, transforming marine biology. Because the ocean is often dark and visibility is limited, sound is one of the most important tools whales have.