Evolution of cetaceans "Caperea marginata") all have derived characteristics presently unknown in any cetothere and vice versa (such as a sagittal crest). The adaptation of echolocation occurred when toothed whales (Odontoceti) split apart from baleen whales, and distinguishes modern toothed whales from fully aquatic archaeocetes. This happened around 34 million years ago in a second cetacean radiation. Modern toothed whales do not rely on their sense of sight, but rather on their sonar to hunt prey. Echolocation also allowed toothed whales to dive deeper in search of food, with light no longer necessary for navigation, which opened up new food sources. Toothed whales
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,