Ecology
Blue whales, the world's largest predators, can perform acrobatic exercises and rotate their bodies 360 degrees while hunting for small sea crustaceans called krill.
Blue whales are currently the only whales of the minke whale genus that can perform such coups.
Other whales are able to move their bodies between 90 and 150 degrees, according to research published in the Royal Society Biology Letters.
Blue whales grow up to 30 meters in length and can weigh up to 180 tons, so making acrobatic steps with these dimensions is quite an achievement. These massive mammals perform the trick in two rounds.
Research author Jeremy Goldbogen said that the whale first makes a 180 degree turn before opening its mouth, and then makes another lunge with its mouth open, collecting water with a huge number of crustaceans. On the second run, the whale rotates 180 degrees further in the same direction, so it can make a full circle. This maneuver is achieved by using strong blows with the tail fin and turning the fins.
Goldbogen and his colleagues noticed that whales can perform such incredible acrobatic exercises after they attached special sensory tags on suction cups to the blue whale's body. They watched the whale hunt in waters off the coast of California.
Scientists have noticed that the whale made a full turn in the water not only during the hunt, but also when it was looking for suitable prey. Scientists believe that this way the whale increased its chances of catching as much nutritious krill as possible.
Whale nutrition features
Due to the sheer size of a whale's body, krill can easily spot it nearby. If whales attack from below, they have a chance to go unnoticed. Indeed, when turning, the whale tries to collect water with nutritious krill when it gets below. This may sound strange, but the whale's sheer size explains why these animals primarily feed on krill.
“We believed that blue whales feed on krill because they have huge bodies and limited maneuverability,” Goldbogen explained. “It is because of the size that the whale cannot keep up with the fish and other larger marine life.”
Nevertheless, krill is good at hiding, but when a whale opens its incredibly huge mouth, tons of water enter it along with a large number of small living creatures that can't to escape.
Researchers have previously noticed that crocodiles also perform special maneuvers while hunting, but their body weight is much less than that of whales. Goldbogen and his colleagues are going to assess in the near future how much energy a whale needs to perform its hunting maneuvers. It is likely that whales may use different acrobatic techniques.