The mouths of whales filter krill for food via sheets of feathered horn, or baleen.

Baleen whales have specialized structures that enable them to efficiently consume small organisms, especially tiny shrimp-like crustaceans called krill. Krill swarm in huge clouds in the ocean, where baleen whales scoop them up, water and all, and send them through a baleen filter-feeding system.

Mostly made of keratin—the same substance found in human fingernails and hair—baleen is similar to the bristles on a brush. It lines the whale’s upper jaw in plate-like structures with fringy tips. In baleen whales, these structures replace the bony teeth that are found in toothed whales. When a baleen whale consumes a huge mouthful of krill, small fish, and water, it partially shuts its jaws and then presses its tongue against its upper jaw to force the water through the baleen, leaving the krill and fish on the inside of the filter for the whale to swallow.

This strategy was co-contributed by EcoRise Youth Innovations.

Watch blue whale feeding behavior

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Scientists at Oregon State University used a research drone to capture footage of blue whale feeding behavior. At 0:35‑0:50 this video shows how the whale enlarges its mouth to capture krill. The rest of the video discusses how whales make choices about what's worth the energetic cost of eating.

Last Updated November 16, 2017