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The orca's teeth are very strong, and its jaws exert a powerful grip; the upper teeth fall into the gaps between the lower teeth when the mouth is closed. The firm middle and back teeth hold prey in place, while the front teeth are inclined slightly forward and outward to protect them from powerful jerking movements.
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 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.
The genus Orcinus was published by Leopold Fitzinger in 1860, [4] its type species is the orca named by Linnaeus in 1758 as Delphinus orca.Taxonomic arrangements of delphinids published by workers before and after Fitzinger, such as John Edward Gray as Orca in 1846 and Orca (Gladiator) in 1870, are recognized as synonyms of Orcinus.
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 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 ...
Cetacea (/ s ɪ ˈ t eɪ ʃ ə /; from Latin cetus 'whale', from Ancient Greek κῆτος () 'huge fish, sea monster') [3] is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises.
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