Unlike toothed whales that hunt for individual prey, baleen whales -- including the blue whale, the largest animal on Earth -- eat an enormous quantity of food in one big gulp. When a blue whale opens its mouth 80 degrees, it can hoover up large schools of tiny crustaceans called krill, consuming as much as 1,100 lbs. (500 kg) at a time. And for a blue whale, a single mouthful of food can contain 457,000 calories, making each foray a relatively efficient and satisfying meal.
A whale of an appetite:
- Instead of teeth, filter-feeding whales use baleen, which are plates with frayed edges in the upper jaw that filter out tiny seafood from the water.
- Baleen whales' feeding efficiency is unprecedented, says researcher Robert Shadwick. “When they take a gulp of water, they are filling their mouths with the amount of water equal to their own body mass.”
- Plates of baleen are made of keratin, a protein found in hair, fingernails, and feathers.