Blue whales can grow to 90 feet -- that's longer than a tennis court. Getting that big requires a lot of fuel, says Jeremy Goldbogen, a postdoctoral researcher at the Cascadia Research Collective. That's why Goldbogen studies the whales' dining habits
. They feed on krill, slurping in millions of the mini crustaceans along with hundreds of thousands of pounds of water in a single gulp. With the help of data tags and a National Geographic Crittercam, Goldbogen and colleagues found that blue whales do underwater acrobatics while they eat
-- specifically a move they coined "the blue whale barrel roll."
Footage: National Geographic Crittercam, Greg Marshall, Jeremy Goldbogen Photos: Ari Friedlaender, Martin Dee, Shutterstock, NOAA, Fisheries and Oceans Canada, Moira Galbraith Illustration: Carl Buell Music: Chris Breemer/Debussy