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.
