Whale than males. Baleen whales have no teeth; instead they have plates of baleen, a fringe-like structure used to expel water while retaining the krill and plankton which they feed on. They use their throat pleats to expand the mouth to take in huge gulps of water. Balaenids have heads that can make up 40% of their body mass to take in water. Toothed whales, on the other hand, have conical teeth adapted to catching fish or squid. Baleen whales have a well developed sense of "smell", whereas toothed whales have well-developed hearing − their hearing, that is adapted for both
Baleen whale contain the Sei whale, Bryde's whale, Eden's whale, the blue whale, and Omura's whale. Cetotheriidae consists of only one living member: the pygmy right whale ("Caperea marginata"). The first descriptions date back to the 1840s of bones and baleen plates resembling a smaller version of the right whale, and was named "Balaena marginata". In 1864, it was moved into the genus "Caperea" after a skull of another specimen was discovered. Six years later, the pygmy right whale was classified under the family Neobalaenidae. Despite its name, the pygmy right whale is more genetically similar to rorquals and gray whales than