Humpback whales create the loudest sound of any living creature.
Humpback whale (Megaptera novaeangliae) is a Baleen whale. One of the larger rorqual species, adults range in length from 12–16 metres (40–50 ft) and weigh approximately 36,000 kilograms (79,000 lb). The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the water. Males produce a complex whale song, which lasts for 10 to 20 minutes and is repeated for hours at a time. The purpose of the song is not yet clear, although it appears to have a role in mating.
Wikipedia Article - Whale song
Both male and female humpback whales can produce sounds, however only the males produce the long, loud, complex "songs" for which the species is famous. Each song consists of several sounds in a low register that vary in amplitude and frequency, and typically lasts from 10 to 20 minutes. Songs may be repeated continuously for several hours; humpback whales have been observed to sing continuously for more than 24 hours at a time. As cetaceans have no vocal cords, whales generate their song by forcing air through their massive nasal cavities.
Whales within an area sing the same song, for example all of the humpback whales of the North Atlantic sing the same song, and those of the North Pacific sing a different song. Each population's song changes slowly over a period of years —never returning to the same sequence of notes.
Scientists are still unsure of the purpose of whale song. Only male humpbacks sing, so it was initially assumed that the purpose of the songs was to attract females. However, many of the whales observed to approach singing whales have been other males, with the meeting resulting in a conflict. Thus, one interpretation is that the whale songs serve as a threat to other males. Some scientists have hypothesized that the song may serve an echolocative function. During the feeding season, humpback whales make altogether different vocalizations, which they use to herd fish into their bubble nets.