Blue whales execute 360 degree rolls to capture prey
World’s largest predators – the blue whales – execute acrobatic 360-degree rolls while feeding on their small crustacean krill prey.
Blue whales are now the only known rorqual whales – the largest group of baleen whales – that can complete a full circle roll. Other whales only go around 90-150 degrees.
Considering that blue whales grow close to 100 feet long and can weigh around 397,000 pounds, the feat is quite an achievement. The massive mammals manage the trick in two steps, the ‘Discovery News’ reported.
The first phase starts with an “180 degree roll prior to mouth opening, when the lunge occurs as the whale opens its mouth and engulfs the prey-laden water, which in this case is krill,” lead author Jeremy Goldbogen said.
For the second phase, there’s “a further 180-degree roll in the same direction to complete the 360-degree spin. This maneuver is powered by several powerful fluke strokes and the tilting of the animal’s flippers.”
Goldbogen, a postdoctoral researcher at Cascadia Research Collective, and his colleagues discovered the move after attaching suction cup multi-sensor tags to blue whales foraging in the waters off of southern California.
Researchers recorded the full circle move not only when whales were feeding, but also when the marine mammals were in a searching mode between lunges.
“We think that this behaviour improves the whale’s chances of engulfing the most amounts of krill possible,” Goldbogen said.
Because of their enormous size, blue whales can be easily detected by krill. If they attack krill from below, however, they might be able to avoid being seen, Goldbogen said.
The study was published in the Royal Society Biology Letters.