Cetacea and two (external) limbs that are modified into flippers. Though not as flexible or agile as seals, cetaceans can swim very quickly, with the killer whale able to travel at in short bursts and the fin whale able to cruise at . Dolphins are able to make very tight turns while swimming at high speeds. The hindlimbs of cetaceans are internal, and are thought to be vestigial. Baleen whales have short hairs on their mouth, unlike the toothed whales. Cetaceans have well-developed senses—their eyesight and hearing are adapted for both air and water, and baleen whales have a tactile system
Toothed whale Seas. The global UNEP Convention on Migratory Species currently covers seven toothed whale species or populations on its Appendix I, and 37 species or populations on Appendix II. All oceanic cetaceans are listed in CITES appendices, meaning international trade in them and products derived from them is very limited. Numerous organisation are dedicated to protecting certain species that do not fall under any international treaty, such as the Committee for the Recovery of the Vaquita, and the Wuhan Institute of Hydrobiology (for the Yangtze finless porpoise). Various species of toothed whales, mainly dolphins, are kept in captivity, as well as