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.





HOW DOES A BLUE WHALE MOVE? Blue Whales: Swimming, Diving and Feeding



Scientists are only realising now the full extent of the Blue Whale’s phenomenal ability in the water. Find out more about the Blue Whales ability to swim extraordinary distances, dive to extreme depths and reach impressive top swimming speeds.



As everyone knows, the Blue Whale is enormous and is the single largest living animal on the planet, growing up to 30 metres in length when fully mature. Even early whalers stayed clear of the Blue Whale, not only because of its sheer size, capable of capsizing the largest of wooden vessels, but also because it was too fast to pursue in open topped man-powered rowing boats armed with nothing but a harpoon gun.



Blue Whales: Swimming & Migration



Typically, a Blue Whale will swim at a speed of 14 miles per hour, far faster, in comparison, to the Sperm Whale, which travels much slower at 6 miles per hour. However, the Blue Whale is able to swim as fast as thirty miles per hour for short periods, for example when it is fleeing potential danger.



Marine mammal expert Bruce Mate, from Oregon State University, tagged one hundred Blue Whales off the coast of California and tracked their movements via satellite throughout much of the 1990s. The research was surprising because it found that Blue Whales travel rapidly from one feeding area to another, and continue to feed throughout the entire year, unlike many other species of whales. Indeed, research shown on the National Geographic’s Kingdom of the Blue Whale, proves conclusively that Blue Whales feed in tropical waters in winter months.



Interestingly, other whales, including grey and humpback whales, don’t feed during the autumn migration and winter breeding season. In comparison to their summer feeding areas, these lower latitude mating and calving grounds are what the Oregon scientists describe as ‘biological deserts.’



Due to their sheer size and the amount of krill – the small shrimp-like animal that Blue Whales feed on almost exclusively, consuming as much as four tonnes each day. Since they need such a large volume of food, they move quickly from one high productivity area to another, usually at a speedy pace.



Scientists believe that the huge fat reserves and the rapid movement in search of food have evolved to allow blue whales to survive potentially devastating events. During the strong El Nino of 1998, most migrating whales seen near California were visibly starved.



Like other whale species Blue Whales start migrating to warmer weather in the autumn. But unlike other whales that migrate in large groups and never stop, if an individual blue whale comes across a good feeding ground they may stay there for weeks before continuing on its migratory route. Interestingly, even the winter destination of Northern Pacific blue whales—a region off Central America called the Costa Rica Dome—is rich with krill. This points to the necessity of a continuous food supply for Blue Whale survival, as opposed to other species of whale who often forgo feeding in the winter months and rely on fat stores to keep them alive.



Blue Whales and Diving



The Blue Whale typically dives less than 330 feet when feeding and can only stay submerged for 10 to 20 minutes, but is capable of diving as deep as 1,640 feet. In comparison, the Sperm Whale, though a slower swimmer, is the deepest diving whale species alive, capable of diving to depths as low as 3,300 feet (1000 metres) and holding it’s breath for up to an hour. Sperm whales need to be able to dive for longer and deeper because they hunt for giant squid, which live on the bottom of the ocean floor.



How Do Blue Whales Dive?



Scientists have often been puzzled by the ability of marine mammals, such as whales, dolphins and seals to dive to such great depths, which at first glance appear to be well beyond their physical abilities. Recent video studies of marine mammals, including that of a 100 tonne Blue Whale off the coast of northern California, has finally revealed, how exactly, marine mammals dive. Video cameras mounted on the animals' backs revealed that all marine mammals start their dives with a few powerful swimming strokes, before making the rest of the descent in what can best be described as a relaxed glide.



As Blue Whales and other marine mammals dive, they are able to reduce their oxygen consumption by 10 to 50 percent by not actively swimming all the way down. They essentially turn their “motor” on and off as they dive, and coast down the pressure gradient.



The change in buoyancy due to increasing pressure with depth allows marine mammals to sink effortlessly. Interestingly, the range of marine mammals with the same style of diving was striking and includes whales, dolphins and seals. These mammals all have lungs that are designed to collapse progressively with increased pressure at depth so air is forced into the upper part of the respiratory system. The change in depth compresses the animal’s body and forces the air in the lungs into a smaller volume, which changes the buoyancy. They can dive and resurface with ease and without getting the bends, a life-threatening affliction of divers who resurface too quickly from dives.



Humans and other land mammals don’t have the ability to dive and resurface quickly because air gets trapped as the lungs are compressed, which forces nitrogen into the bloodstream and causes the bends. Marine mammals make their dives long by relaxing and consuming less oxygen on the way down.

