My Discovery W hales produce the loudest sustained sounds in the animal kingdom. The moan of a blue whale can last up to 30 seconds at 188 decibels. By comparison, a 747 jet generates about 110 decibels of perceived sound at take-off.
Scientists know little about the meaning of whale sounds.
Contrary to a popular misconception, researchers have not isolated anything close to a language in whale songs. But they have identified the repetitive sounds that comprise songs. To the whales themselves, the songs may be a sexual come-on or a way to maintain space between individuals or establish a position in the social order. Maritime lore is filled with stories of sailors hearing siren songs and mysterious sounds at sea, but it wasn't until the 1950s that these underwater noises were first recorded by the military. Many whale-watching tours now carry hydrophones so that passengers can listen to nearby whales.