Krill are small, shrimp-like crustaceans found in oceans around the world, particularly in the Southern Ocean surrounding Antarctica. They play a crucial role in the marine food web, serving as a primary food source for various animals, including whales, seals, and penguins. These tiny creatures are typically less than 6 centimeters long and are known for their swarming behavior, forming large groups called swarms. Krill feed on phytoplankton, which are microscopic plants that thrive in sunlight-rich waters. Their abundance makes them vital for maintaining the balance of marine ecosystems.