Humpback whales sing long, repeating songs that can travel for many kilometres through deep water.

The longer version

Low notes lose very little energy in water, which is why a song carries remarkable distances out at sea. The sound is produced by moving air through internal passages, so no breath needs to escape while a phrase plays. Sequences are organised into themes repeated for minutes or hours.

Each population shares a version that slowly changes from season to season, with neighbours picking up new phrases from one another. Deep layers where sound speed reaches a minimum bend travelling waves back inward, helping the signal persist far beyond the singer, so contact is kept across darkness.

Where this entry sits

Oceans and Sea Life looks at the salt water that covers most of the planet, from crashing waves and tides to the darkest deep-sea trenches. Expect notes on coral, fish, whales, sharks, jellyfish, shells, and the strange creatures that live far below the surface. The full list sits on the Oceans and Sea Life page, where every entry is listed in order.