How far away can the blue whale be heard?”?
The Blue Whale is the second loudest animal in the world (the loudest is the sperm whale ). Estimates made by Cummings and Thompson (1971) and Richardson et al (1995) suggest that source level of sounds made by Blue Whales are between 155 and 188 decibels when measured at a reference pressure of one micropascal at one metre. Even accounting for different acoustic impedances between water and air and different standard reference pressures, an equivalent sound range in air is 89–122 decibels. By comparison, a pneumatic drill is about 100 dB. A human, however, would likely not perceive the Blue Whale as the second loudest of all animals. All Blue Whale groups make calls at a fundamental frequency of between 10 and 40 Hz, and the lowest frequency sound a human can typically perceive is 20 Hz. Blue Whale calls last between ten and thirty seconds. Additionally Blue Whales off the coast of Sri Lanka have been recorded repeatedly making “songs” of four notes duration lasting about two mi