Ari Friedlaender
While feeding, whales sometimes roll over to maximize their catch.
To capture enough food for their enormous bodies, blue whales use an extreme technique called lunge feeding: they take enormous gulps of water, then let it pass through comb-like mouth filters called baleen, keeping krill behind for consumption.
And sometimes, a new study reports, they also do an acrobatic roll to help them capture krill more effectively.
Writing in Biology Letters, researchers explain that the whales sometimes roll 180 degrees, so their backs face the seafloor as they accelerate and move forward to open their mouths for a lunge.
?They engulf from right beneath the krill patch so they are less likely to be seen,? said the study?s first author, Jeremy Goldbogen, a comparative physiologist at the Cascadia Research Collective in Olympia, Wash. ?This minimizes the escape of the krill.?
The whales complete their roll, flipping over another 180 degrees, while filtering water through their mouths.
?The whole process can be finished in about 20 to 30 seconds,? Dr. Goldbogen said. That is pretty fast, considering that blue whales are the world?s largest animals.
Dr. Goldbogen and his colleagues studied 22 whales living off the coast of Southern California. Only about half used the technique while they were being monitored, and those whales did it only about 10 percent of the time.
?They may be using it in very small krill patches as a way to minimize the krill escape response,? Dr. Goldbogen said; when there are dense patches of krill, the acrobatic maneuver may not be necessary.
Dr. Goldbogen believes that other lunge feeders may use the technique as well.
?We haven?t observed it yet,? he said, ?but with more research and more tags we?re likely to find it in other closely related whales, like fin whales.?
w.e. episodes idris elba kelsey grammer martin henderson mlk day golden globes 2012 winners
No comments:
Post a Comment