露脊鯨
Right whale dolphins are cetaceans belonging to the genus Lissodelphis. It contains the northern right whale dolphin ("Lissodelphis borealis") and the southern right whale dolphin ("Lissodelphis peronii"). These cetaceans are predominantly black, white beneath, and some of the few without a dorsal fin or ridge. They are smaller members of the delphinid family, oceanic dolphins, and very slender. Despite scientists being long acquainted with the species (the Northern species was identified by Titian Peale in 1848 and the Southern by Bernard Germain de la Cépède in 1804), little is known about them in terms of life history and behaviour.