This is Scientific American's 60-second Science, I'm Susanne Bard.During the summer, blue whales in the Northeastern Pacific spend their days feeding on massive amounts of tiny plankton called krill.In fact, krill is all they eat.“It really is remarkable that such a small animal is able to sustain the largest life form that’s ever existed on this planet.”Stanford University marine ecologist Will Oestreich.“And to maintain themselves at that body size, they have pretty extreme feeding habits.”A blue whale consumes many tons of krill every day.Eating keeps the ocean giants occupied during daylight hours, when they dive hundreds of feet below the surface, where krill congregate in dense swarms.But at night, when their prey disperse, the whales start to sing.“And they’ll sing for 10, 12 hours straight.”The song you just heard was sped up 10 times.“Which brings the sound up more into human hearing range.”Speeding up the song enables researchers to more easily study whales’ deep and resonant songs, which can be heard by other whales across vast distances in the ocean.“It’s very likely that song in blue whales is related to some sort of reproductive function, whether that’s attracting a mate or warding off other males.”Since 2015, the Monterey Bay Aquarium Research Institute has been recording the songs of blue whales with an underwater microphone attached to the seafloor.
