Humpback Whale Feeding Using Baleen (IMAGE) Smithsonian Caption Baleen is the soft, hair-like structure on the upper mouth of whales, such as the humpback whale in this photo, which allows them to trap prey in their mouth. When whales first evolved, they used teeth to chew their food, just like their land-dwelling ancestors. As time went on, many descendants of these early whales continued to chew their food, inheriting this trait from their predecessors. But as the oceans around them changed and animals evolved, entirely new feeding strategies arose, including baleen filter feeding. Peredo and Pyenson see studying whale evolution as key to understanding their survival in today's rapidly changing oceans. Like the emergence of baleen, tooth loss in whales is evidence of adaptability, suggesting that whales might be able to adapt to challenges posed in the ocean today. Still, Peredo cautions, evolutionary change may be slow for the largest whales, which have long life spans and take a long time to reproduce. Credit Ari S. Friedlaender/University of California, Santa Cruz under NOAA permit Usage Restrictions News-media use of these photos in relation to this study is permitted with attribution. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.