WASHINGTON—The first study to methodically calculate how much food blue whales and some other similar-looking types eat has yielded a simple answer: a whole lot. The blue whale, the largest animal on Earth, eats about 16 tons of krill daily in the North Pacific, gobbling up these tiny shrimp-like crustaceans with a filter-feeding system in the mouth using baleen plates made of keratin, the substance found in people’s fingernails, scientists said on Wednesday. “That is roughly the weight of one fully loaded school bus,” said study co-author Nick Pyenson, curator of fossil marine mammals at the Smithsonian Institution’s National Museum of Natural History in Washington. The researcher’s calculated daily food intake for seven baleen whale species, tracking 321 individual whales in the Atlantic, Pacific, and Southern Oceans from 2010 to 2019. These gigantic marine mammals were found to eat up to three times more food than previous estimates that were …