Krill are planktonic crustaceans and their larvae that constitute the principal food source for baleen whales, such as the Humpback, Fin, and Minke whales shown here. Most krill are only 1-2 centimeters long (visually similar to a miniature shrimp), but their combined biomass worldwide is among the largest for all species.

Krill are endangered by the warming climate and by overfishing (for dietary oil supplements, animal feed, and food products like sauces).