Baleen is a filter-feeding system found in some species of whales, such as blue whales and humpback whales. It consists of long, flexible plates made of keratin, the same material as human hair and nails. These plates hang from the upper jaw and help the whale capture small prey like krill and small fish from the water. When a baleen whale feeds, it takes in a large mouthful of water and then pushes the water out through the baleen plates. The baleen traps the food inside, allowing the whale to swallow its meal. This unique adaptation enables baleen whales to thrive in various ocean environments.