The blue whale (Balaenoptera musculus) is not only the largest animal to ever live on earth – yes, it was larger than any dinosaur – it also is the loudest animal on earth (the howler monkey is second).
Calls from a blue whale can reach up to 188 decibels, which is louder than a jet engine and can be heard in the ocean for hundreds of miles. Some researchers believe the sound of a blue whale can cross an entire ocean.
Swimming at approximately 5 miles per hour (8 km/hr), the blue whale can accelerate to 20 miles per hour (32 km/hr) to escape predators, attack prey or to avoid a disturbance.Found in all oceans of the world, the blue whale often travels in alone or in pairs, though occasionally they have seen traveling in small groups. They typically spend the summer months in polar waters and then begin their long, annual migration toward the waters of the Equator, where they spend the winter months.
How sound is made
The source of whale sound production is unknown, but the larynx is the likely source. Unlike humans, whales have no vocal cords in their larynx. Whales produce sounds two ways: by moving air through a tubed extension of the larynx to the nasal plugs (located near the nasal sacs near the blowhole). It is believed that whale sounds are mostly produced in the larynx region and the nasal sacs, as air is moved between nasal sacs and that whale whistles are produced in the nasal plugs.
With pod populations in every ocean, the blue whale is one of the most recorded animals in the ocean. Researchers with the National Oceanic and Atmospheric Association have recorded the blue whale in various locations. Each of the following recordings has been sped up 10 times its normal play rate so that they are easier for human ears to hear. By carefully listening to each recording you can hear faint differences between the regions where the recordings where made. Researchers still have more questions than answers when it comes to translating the various calls and songs of whales, but work is underway to learn more about these beautiful sounds.
Northeast Pacific Ocean
Probably the most popular blue whale calls in the world are those taken in the waters of the Northeast Pacific Ocean. These calls usually have two parts: A and B. The A part of the call is a series of pulses (approximately 1.5 pulses/second); the B part of the call is a long frequency-modulated (FM) moan. Occassionally a third sound will appear, this C part is a short upswept call lasting 8 seconds or less and is sandwiched between the A and B parts of the call.
Western Pacific Ocean
Western Pacific blue whale calls have been recorded primarily in the northwestern Pacific but also north of Hawaii and in the offshore northeast Pacific. They are generally a one to two-part frequency modulated moan that lasts about 20 seconds with frequencies from 23-20 Hz.
South Pacific Ocean
These blue whale calls were recorded by an array of six hyrdrophones in the Equatorial Pacific Ocean as part of the U.S. Navy’s SOSUS system. These calls are complex and variable and resemble calls reported for blue whales off the coast of Chile in the 1970s.
Atlantic blue whale calls are narrow-band, low frequency moans (~ 19 Hz, slight downsweep of ~ 1 Hz) that last, on average, 16 seconds. This call was recorded on the northeastern phone of the autonomous hydrophone array located along the mid-Atlantic ridge.
CUMMINGS, W.C. and P.O. THOMPSON. 1971. Underwater Sounds from the Blue Whale, Blaenoptera musculus. J. Acoust Soc Am 50(4): 1193-1198.
NORRIS, K.S. 1968. The evolution of acoustic mechanisms in odontocete cetaceans. in : E. Drake, ed. Evolution and Environment. Yale Univ. Press.
PURVES, P.E. 1967. Anatomical and experimental observations on the Cetacean sonar system. in : R.G. Busnel, ed. Animal Sonar Systems : Biology and Bionics. Laboratoire de Physiologie Acoustique, Jouy-en-Josas 78, France. pp. 197-270.
SMALL, G.L. 1971. The Blue Whale. Columbia University Press, New York, 248p.