Blue Whales and Communication Studies over the last forty years have shown that Blue Whales have evolved sophisticated modes of communication that allow them to speak to one another across immense Oceans.
During the darkest days of the Cold War, US Navy officials, listening out for Soviet submarine activity in the northern Pacific Ocean, using the latest hydrophone system, noted that one of the main sounds they continually heard were those of whales, often many miles away, communicating to one another across the sea.
Since scientists have gained access to that network of undersea listening outposts, they have worked to find out if, how, and why whales communicate to one another across the oceans.
Blue Whale Sounds
Sound is the most effective way to communicate across a vast expanse of ocean – travelling at a speed of five times greater under water than in the air - so it’s not surprising then to discover that Blue Whales have evolved the ability to communicate with sound across the water.
Tests and studies have shown that all whale species use sound for a number of different purposes: to navigate, to detect food, and to communicate with one another over long distances. Despite the breakthroughs in determining the role of sound in whale activities, much about the Blue Whale sounds remains something of a biological mystery.
Blue Whales are relatively solitary animals, usually found alone, or in pairs of mother and calf or two adults, but even then they sometimes swim several kilometres apart.
Due to their solitary lifestyles, Blue Whales have evolved an exceptional way of speaking to one another across huge distances. As you would expect from the largest animal on the planet, Blue Whales have exceptionally deep voices and are able to be vocal at frequencies as low as 14 Hz - well below the ability of human hearing - with a volume greater than 180 decibels, which makes the Blue Whale the loudest animal on the planet.
The sounds they make that humans can hear are characterised by low grunts, humming, moans and clicks. The deep vibrations and sounds created by a Blue Whale can travel thousands of miles across the sea and may have evolved to take advantage of the ocean's sound channel.
"One of the challenges in understanding the status of this species is knowing how many are out there," said National Geographic in-house marine biologist John Francis, based at Society headquarters in Washington D.C. Remotely listening to and measuring whale song, which travels for thousands of miles, is one off-beat option.
The Impact of Noise Pollution on Whales
There is increasing evidence to suggest that noise pollution from modern shipping, military sonar activity and leisure boats is having an adverse effect on the way whales communicate and how they act. Although many whale calls are too low for the human ear to pick up, most human noise pollution on the seas is at a similar ambient noise level to that used by whales to communicate, causing possible confusion to the animal as it navigates or looks for a mate.
The haunting call of the blue whale is the most intense of any animal alive. These rhythmic pulses and deep moans are so loud they travel across entire oceans, yet the frequency of these calls is often so low that they are totally inaudible to human ears.
Scientists at Cornell University in the US, who undertook a study into the effects of noise pollution on Blue Whales believe that twenty to twenty-five million years of evolution are being undone in a hundred years thanks to increased noise pollution from humans.
The Cornell scientists also point out that since the average life span of a Blue Whale is 90 years old, there are whales alive today that might remember when they only heard the calls of other whales across vast stretches of ocean.
Other research shows that Blue Whales are only able to hear up to 100 miles (160 kilometres) away today, compared with the 1,000-mile (1,600-kilometre) acoustic range they had in 1940. The same study even notes that other whale species such as the Right Whale communicate at frequencies two thirds of an octave higher than they did a century ago, possibly as way to combat and communicate above the din of ocean noise pollution.
Scientists believe that the very-low-frequency courtship songs of Blue Whales are the most powerful biological sounds in the ocean and they hypothesize that whale songs evolved to take advantage of the ocean's sound channel, especially for some of their most important kinds of communication, including finding a mate.
Interestingly, only male Blue Whales sing loud songs, suggesting a reproductive reason for the calls, which are potentially being cancelled out by the din of modern shipping.
Potentially, if noise pollution means that Blue Whales are struggling to find mates across the vast ocean waters, it could have a dramatic effect on any attempts to increase their numbers and move them off the endangered species list.
Do Blue Whales Have Dialects?
Although there is no way to know if Blue Whales have accents, research into the calls and sounds of Blue Whales suggests that they may – bizarrely - have different dialects, depending on where in the ocean they are found.
Researchers in the US from the Scripps Institution of Oceanography at the University of California in San Diego undertook a study in 2007 to determine worldwide Blue Whale populations by analysing different song patterns. They found that Blue Whales in different parts of the sea actually make different sounds.
The Scripps team of scientists was able to create a map categorising Blue Whale species types into nine geographical regions around the world based on their song ‘dialects.’
The study found that while some dialects are relatively confined to coastal areas, others are spread over broad geographic areas, such as the entire Northern Pacific Ocean. This lead to suggestions that the stock structures of Blue Whales, traditionally based on International Whaling Commission boundaries, should instead be based on song. By listening to the animals, researchers can tell something about the regions in which the Blue Whales are interacting and breeding, which is important for managing and conserving whale populations.