A krill is a tiny crustacean that serves as a food source for many animals in marine ecosystems all over the world. Most krill are under 2 inches long and look similar to shrimp.
Krill are vital to the bottom of the food chain in the oceans because nearly every marine animal eats krill or eats another organism that feeds on krill. The biggest consumers of krill are whales, penguins, fish, squid and seals, which collectively consume over half of all krill in the world. On average, 379 million tons of krill are present in the ocean at any given time, and they reproduce fast enough to continually replenish.