Two kinds of whales sport baleen. Balaenid whales, such as the bowhead, have long, springy plates with a delicate fringe. They filter water continuously. Groove-throated whales such as humpbacks have dense baleen that looks like a folded accordion. They gulp water to feed.
For the tests, Werth submerged racks of humpback and bowhead baleen in a flow tank. Plastic beads represented food. As water streamed by, filaments from neighboring baleen plates naturally twined together and trapped the beads. The bowhead's long fringe formed the more effective filter—perfect for catching tiny krill. But the humpback baleen still nabs plenty. The study is in the Journal of Experimental Biology. [Alexander J. Werth, Flow-dependent porosity and other biomechanical properties of mysticete baleen]
If you’re going to be a massive carnivore without teeth, evolution has to be especially creative.
—Marissa Fessenden
