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
Whaling in Japan of extinction within a few decades according to IWC population estimates. In Japan, not only humpback, minke, and sperm whales, but many other smaller toothed whales, including species such as western gray, the endangered North Pacific right, and northern fin whales have been targets of illegal captures utilizing harpoons for dolphin hunts or intentionally drive whales into nets. Reports are later filed with administrative organs or research institutions as cases of "entanglements where fishermen tried their best to save whales". Products from internationally protected species' meat can also be found on markets even today mostly originating as "by-products" of entanglements,