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The orca (Orcinus orca), or killer whale, is a toothed whale and the largest member of the oceanic dolphin family. It is the only extant species in the genus Orcinus and is recognizable by its black-and-white patterned body. A cosmopolitan species, it inhabits a wide range of marine environments, from Arctic to Antarctic regions to tropical seas.
The orca is known to prey on numerous other toothed whale species. One example is the false killer whale. [69] To subdue and kill whales, orcas continually ram them with their heads; this can sometimes kill bowhead whales, or severely injure them. Other times, they corral their prey before striking.
In comparison, the modern killer whale has teeth around 8 cm (3.1 in) in height and 2.5 cm (0.98 in) in diameter. [3] Like the modern killer whale, the tooth lacks a coat of cementum. However, unlike the modern killer whale, O. paleorca had a circular tooth root as opposed to an oval, and the pulp extended more towards the back than the front. [2]
The scientists also discovered signs of orca tooth rake marks on the dorsal fin of a fin whale (Balaenoptera physalus). While there are no observations of orcas hunting fin whales, orcas are known ...
Later species reduced the number of toes, and developed teeth more suited for grinding up grass and other tough plant food. Rhinocerotoids diverged from other perissodactyls by the early Eocene. Fossils of Hyrachyus eximus found in North America date to this period. This small hornless ancestor resembled a tapir or small horse more than a rhino.
The common name was chosen because the part of the tooth that protrudes from the gums (unlike the strap-like teeth of strap-toothed whales) has a shape similar to the tip of a flensing spade as used by 19th-century whalers. Despite the rather similar dentition, the spade-toothed whale and strap-toothed whale seem to be only distantly related.
That means baleen whales make their sounds with their larynx, as do humans, while toothed whales - including dolphins, porpoises, killer whales and s Scientists discover the anatomy behind the ...
The transition from teeth to baleen is proposed to have occurred stepwise, from teeth to a hybrid to baleen. It is known that modern mysticetes have teeth initially and then develop baleen plate germs in utero , but lose their dentition and have only baleen during their juvenile years and adulthood.