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
Abralia suggest that these may not form natural groupings. They have worldwide distribution in tropical and subtropical seas. They spend the day at depths below 600m and at night they move to less than 200m in depth. These quid are important prey species for large fish such as tuna and billfish as well as toothed whales. The following species are currently recognised and are divided into six subgenera: Abralia Abralia is a genus of squid comprising around 20 species from the family Enoploteuthidae. They are small squid which can be found in the epipelagic to mesopelagic zones while some species are