Portal:Cetaceans
The Cetaceans Portal
Cetacea (/sɪˈteɪʃə/; from Latin cetus 'whale', from Ancient Greek κῆτος (kêtos) 'huge fish, sea monster') is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel themselves through the water with powerful up-and-down movement of their tail which ends in a paddle-like fluke, using their flipper-shaped forelimbs to maneuver.
While the majority of cetaceans live in marine environments, a small number reside solely in brackish water or fresh water. Having a cosmopolitan distribution, they can be found in some rivers and all of Earth's oceans, and many species inhabit vast ranges where they migrate with the changing of the seasons.
Cetaceans are famous for their high intelligence, complex social behaviour, and the enormous size of some of the group's members. For example, the blue whale reaches a maximum confirmed length of 29.9 meters (98 feet) and a weight of 173 tonnes (190 short tons), making it the largest animal ever known to have existed.
There are approximately 89 living species split into two parvorders: Odontoceti or toothed whales (containing porpoises, dolphins, other predatory whales like the beluga and the sperm whale, and the poorly understood beaked whales) and the filter feeding Mysticeti or baleen whales (which includes species like the blue whale, the humpback whale and the bowhead whale). Despite their highly modified bodies and carnivorous lifestyle, genetic and fossil evidence places cetaceans as nested within even-toed ungulates, most closely related to hippopotamus within the clade Whippomorpha. (Full article...)
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Baleen makes up baleen plates, which are arranged in two parallel rows that look like combs of thick hair; they are attached to the upper jaws of baleen whales. It is composed of keratin, which is the same substance that makes up human hair and nails. Whales use these combs for filter feeding. Whales are the only vertebrate group to use this method of feeding in great abundance (flamingos and crabeater seals use similar methods, but do not have baleen), and it has allowed them to grow to immense sizes. The Blue Whale, the largest animal ever to live, is a baleen whale.
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More did you know...
- ...the Humpback Whales song is produced by them forcing air through their massive nasal cavities
- ...baleen from the Mysticeti whales mouths was used to stiffen parts of women's stays and dresses, like corsets
- ...the Sperm Whale was named after the milky-white substance spermaceti found in its head and originally mistaken for sperm.
- ...the Beluga Whale's milkfat is so high, the calf gains up to 2 kilograms per day on the diet. It is so fatty that the colour is green.
- ...the Blue Whale has the largest penis of any animal on earth, estimated at over 2 m (more than 6½ feet)
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- ... that one of the first researchers to propose dolphin-assisted therapy for humans later renounced it?
- ... that the South Asian river dolphin is nearly blind and relies on echolocation for navigation?
- ... that Celia Kaye won the Golden Globe Award for Most Promising Newcomer in 1965 for her starring role in Island of the Blue Dolphins?
- ... that one can swim with humpback whales in the Niue Nukutuluea Multiple-Use Marine Park?
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