Balaenoptera musculus

The largest animal known to have ever lived, blue whales grow up to 30 meters (100 feet) in length. Blue whales, or Balaenoptera musculus, grow to such enormous sizes (up to 140 tonnes, perhaps twice the mass of the heaviest-known dinosaur) lunge-feeding on tiny krill, tiny arthropods less than an inch long. They feed by engulfing enormous volumes of water in a pleated throat pouch that balloons outward (see feeding image below), then as they expel the water they strain the tiny krill out on their baleen plates - tooth-like projections made of keratin that have replaced their actual teeth.