In a recent paper published in PLOS One, Saint Louis University professor of physics Jean Potvin, Ph.D., and biologist Alexander Werth, Ph.D. at Hampden-Sydney College, detail for the first time how baleen whales use crossflow filtration to separate prey from water without ever coming into contact with the baleen. Baleen are comb-like keratin plates that have replaced the teeth of the whale’s ancestors about 30 million years ago and play the role of a filtration surface in their mouths. The researchers looked at how this type of feeding affects a whale’s drag as it moves through the water and how this form of filtration is enhanced by a large body size.