How do whales use sound to communicate across long distances?

Many whales rely on sound because it travels much better in water than light does. Baleen whales such as humpbacks, blues, and fin whales produce low-frequency calls that can travel long distances and may be used for communication or finding mates. Some toothed whales also use clicks and whistles, and species like sperm whales use a series of clicks called codas. The exact range varies with ocean depth, temperature, and background noise, but sound is central to whale social life. Human-made noise from shipping and sonar can interfere with these calls.