Sound is very important to whales for hunting, navigating and communicating. Toothed whales and baleen whales use sound quite differently. Toothed whales and dolphins (for example killer whales and bottle-nose dolphins) use echolocation for hunting and navigating, while baleen whales (for example humpbacks and blue whales) generally produce a series of sounds which are frequently termed ‘songs’ that are used for communicating.
Whale songs consist of distinct sequences of groans, moans, roars, sighs and high pitched squeals that may last up to 10 minutes or longer. It is thought these sounds could be used for communicative purposes such as to identify other individuals, for long-range contact and to warn others of threats as well as navigation. Baleen whales do not have vocal chords so scientists are still unsure how whale songs are produced.
The oceans now resound to a cacophony of underwater noise from ships, echo sounders, seal scaring devices, underwater loudspeakers, explosives, dredging, seismic survey air guns, drilling rigs, and active sonar systems. Although whales and other marine mammals have evolved to cope with natural ambient sounds such as from air bubbles, waves, even earthquakes, there is mounting evidence that the huge increase in human generated noise invading the ocean depths is strongly detrimental to the health and wellbeing of fishes.