| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 1,508,915,731 visitors served. |
|
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
whale |
Also found in: Dictionary/thesaurus, Medical, Wikipedia, Hutchinson | 0.07 sec. |
|
whale, aquatic mammal of the order Cetacea, found in all oceans of the world. Members of this order vary greatly in size and include the largest animals that have ever lived. Cetaceans never leave the water, even to give birth. Although their ancestry has been much debated, DNA studies and skeletal evidence from extinct early whales indicate that whales evolved from the ancestors of artiodactyls, a group that includes hippopotamuses, cows, pigs, and deer.
Characteristics and BehaviorLike other mammals, whales breathe air, are warm-blooded, and produce milk to feed their young. Their adaptations for aquatic life include a streamlined form, nearly hairless skin, and an insulating layer of blubber, which can be as thick as 28 in. (70 cm) in some Arctic species. The forelimbs of whales are modified into flippers, and the hind legs are reduced to internal vestiges. Many species possess a dorsal fin. The tail is flattened into horizontal flukes and is used for propulsion. The head is very large, with a wide mouth and no external neck. Whales have one or two nostril openings, called blowholes, located far back on the top of the head; the nostril valves close and the lungs compress when the whale dives. Most whales must surface every 3 to 20 min to breathe, but some, like the sperm whale sperm whale, largest of the toothed whales , Physeter catodon, found in the Atlantic and Pacific oceans. It is also called cachalot. Male sperm whales may grow to more than 70 ft (21 m) long and females to 30 ft (9 m). Most large whales travel in small schools, or pods, but some, like the fin whale, swim alone or in pairs; small cetaceans form schools of up to several thousand individuals. Most large whales are found in open ocean, where they migrate thousands of miles between feeding and breeding grounds. Dolphins frequently live in coastal waters. A few dolphin species are found in tropical rivers. Females of most species give birth to a single calf every two to three years. Gestation periods range from 9.5 to 17 months. The newborn calf is pushed to the surface by the mother or by another adult; it is able to swim almost immediately and is nursed for 6 to 12 months. Some large whales are believed to have lived 100 years or more in the wild. Types of WhalesThere are two major groups of whales—the toothed whales (suborder Odontoceti) and the toothless baleen whales (suborder Mysticeti). Toothed WhalesToothed whales include two families that are widely distributed, the beaked and bottlenose whales (family Ziphiidae) and the sperm whale, or cachalot (family Physeteridae); the beluga beluga (bəl Toothed whales range in length from 4 to 60 ft (1.3–18.5 m). They catch fast-moving prey, like fish or squid. Many species use echolocation (sonar) for underwater navigation and hunting. They have a single blowhole and a wide throat to accommodate large prey. Some of the larger ones, like the sperm whale, can dive as deep as 1 mi (1.6 km). Toothless WhalesThere are three families of baleen whales: the right whale right whale, name for whales of the family Balaenidae. They were so named by whalers, who for centuries considered them "the right whales" to hunt, because they float when killed and because they yield enormous quantities of oil and of baleen. Baleen whales are large species, usually over 33 ft (10 m) long. They are filter feeders, living on shrimplike krill, plankton, and small fish. They lack teeth but have brushlike sheets of a horny material called baleen, or whalebone, edging the roof of the mouth. With these strainers and their enormous tongues, tons of food can be separated from seawater. Baleen whales have narrow throats and paired blowholes. Male humpbacks produce a repeated pattern of sounds called a song during the mating season; the purpose is not clear, as all males in a group sing basically the same song. WhalingAll species of large whales have been drastically reduced in numbers by centuries of intensive whaling. An indefinite ban by the International Whaling Commission on commercial whaling of all large whales gradually went into effect following the 1984–85 season, and large portions of ocean have been designated whale sanctuaries. With these and various other protective efforts, some species have begun to return to acceptable numbers, but others, especially the right and blue whales, are still rare and endangered. After decades of protection the number of E Pacific gray whales seems to have returned to its estimated prewhaling level. Only the small minke whale exists in populations great enough for sustainable whaling to be considered. Whale products include whale oil whale oil, oil extracted from the blubber and other parts of certain species of whales. It varies in composition, color, and the degree of fishy odor according to the method and extent of refining. ClassificationWhales are classified in the phylum Chordata Chordata (kôrdā`tə,–dä`–) BibliographySee R. Ellis, The Book of Whales (1980) and Dolphins and Porpoises (1989); L. Watson, Sea Guide to Whales of the World (1981). whaleAny of dozens of species of exclusively aquatic mammals found in oceans, seas, rivers, and estuaries worldwide but especially numerous in the Antarctic Ocean. Whales are commonly distinguished from the smaller porpoises and dolphins and sometimes from narwhals, but they are all cetaceans. See also baleen whale; toothed whale. whale 1. any of the larger cetacean mammals, excluding dolphins, porpoises, and narwhals. They have flippers, a streamlined body, and a horizontally flattened tail and breathe through a blowhole on the top of the head 2. any cetacean mammal 3. Slang a gambler who has the capacity to win and lose large sums of money in a casino whale former symbol of demonic evil. [Animal Symbolism: Mercatante, 26] See : Demon whale many species in danger of extinction, owing to massive hunting. [Ecology: Hammond, 290] See : Extinction whale lures fish to mouth with sweet breath. [Animal Symbolism: Mercatante, 27] See : Treachery How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
|
| ? Mentioned in | ? References in periodicals archive | ||
|---|---|---|---|
| In 1986, a 14-foot long male false killer whale and a six-foot long female Atlantic bottlenose dolphin at Honolulu's Sea Life Park Hawaii became the proud parents of Kekaimalu, the first "wholphin" ever born in captivity. Samples of false killer whale had an average total mercury level of 46. The researchers determined that 137 of the samples came from nine species of toothed whales, including false killer whales, pilot whales, and several species of dolphins and porpoises. |
| Encyclopedia |
| Free Tools: |
For surfers:
Browser extension |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup | Partner with us |
|---|