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They may be numerous, with some dolphins bearing over 100 teeth in their jaws. At the other extreme are the narwhals with their single long tusks and the almost toothless beaked whales with tusk-like teeth only in males. [20] In most beaked whales the teeth are seen to erupt in the lower jaw, and primarily occurs at the males sexual maturity. [21]
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. However, developing mysticetes do not produce tooth enamel because at some point this trait evolved to become a pseudogene. This is likely to have occurred ...
Baleen whales have no teeth; instead, they have plates of baleen, fringe-like structures that enable them to expel the huge mouthfuls of water they take in while retaining the krill and plankton they feed on. Because their heads are enormous—making up as much as 40% of their total body mass—and they have throat pleats that enable them to ...
In terms of length, blue whales have often been compared to three school buses lined up back to back. These whales measure 90-100 feet long and are estimated to weigh from 200,000-352,000 pounds ...
Generally their teeth have evolved to catch fish, squid or other marine invertebrates, not for chewing them, so prey is swallowed whole. Teeth are shaped like cones (dolphins and sperm whales), spades , pegs , tusks or variable (beaked whale males). Female beaked whales' teeth are hidden in the gums and are not visible, and most male beaked ...
The degree of calcification varies between species, with the sei whale having 14.5% hydroxyapatite, a mineral that coats teeth and bones, whereas minke whales have 1–4% hydroxyapatite. In most mammals, keratin structures, such as wool , air-dry, but aquatic whales rely on calcium salts to form on the plates to stiffen them. [ 58 ]
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The family Balaenidae, the right whales, contains two genera and four species. All right whales have no ventral grooves; a distinctive head shape with a strongly arched, narrow rostrum, bowed lower jaw; lower lips that enfold the sides and front of the rostrum; and long, narrow, elastic baleen plates (up to nine times longer than wide) with fine baleen fringes.