Filter feeder gap between the two rows of baleen plates lets the water in together with the prey, while the baleens filter out the water. Rorquals such as the blue whale, in contrast, have smaller heads, are fast swimmers with short and broad baleen plates. To catch prey, they widely open their lower jaw — almost 90° — swim through a swarm gulping, while lowering their tongue so that the head's ventral grooves expand and vastly increase the amount of water taken in. Baleen whales typically eat krill in polar or subpolar waters during summers, but can also take schooling fish, especially
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