Cetáceos they are animal marine pertaining to the order Cetacea of the classroom of mammals. The name of the order drift of the Greek ketos that it means monster marine. The cetáceos are divided in two suborders:
- whales without teeth (they subordem Mysticeti) they are characterized by , that they are structures similar to bolters located in the superior part of and is made of . The whales use "beards" to filter of the water. They understand the greaters of .
- whales with teeth (they subordem Odontoceti) they have and if feeds of e . An ability notable of this group is to locate its canine tooth for ecolocalização.
Table of content
The adaptations of the cetáceos to a way completely is sufficiently well-known: the body is , resembling it of one . previous, also called or paddles, is in form of rows. The tip of the tail possesss two horizontal wolves, that they provide propulsion through vertical. The cetáceos do not possess members , some small ones inside of the body is what it remains of pélvis.
Underneath of exists a layer of fat. It serves as reservoir of and also as isolation. The cetáceos possess one of four chambers. vertebrae of neck they are casting in the biggest part of the cetáceos, what it supplies stability during swimming to the costs of flexibility.
The cetáceos breathe through espiráculos, located in the top of of the animal in order that it can remain submerged. whales without teeth they possess two, while that whales with teeth but they have one espiráculo. When they breathe, the cetáceos launch a water spurt, whose form is a characteristic that helps its identification. Its respiratory system allows them to be submerged during much time without breathing: , for example, can be two hours without breathing.
Especially well-known it is , the animal greater that some time lived. It can reach 30 meters of length and weigh 180 tons.
The cetáceos generally are classified as , even so its feeding can only include , as in the whales without teeth, until great .
As all mammals, the cetáceos also , but cannot be completely unconscious to be able to breathe. The solution for this problem was decided by : but one of its sleeps of each time. The cetáceos sleep about eight hours per day.
generally gives to the light alone one creates. The time of gestation he is long (more of the one than one year in many species), with that one strong linking between mother is associated and creates. In the majority of the whales the maturity occurs late, typically of the seven to the ten years. This strategy of reproduction makes with that they have few filhos(as), combined with one high tax of survival.
is reserved in socket in the body during its to swim, of form will produce it efficient a effect hydrodynamic. The majority of the cetáceos does not keep fixed partners during periodo of acasalamento; in many of especies, the females have accompanying varios in each season of acasalamento. In the birth it creates it leaves first with its tail turned for the water, therefore the drowning risk is minimized. The mothers create bebé espremendo its milk actively fat person in the mouth of create them.
Evolution of the cetáceos
The cetáceos and the Human beings
The majority of the species of great cetáceos is in extinguishing danger, as resulted of the hunting to the whale. However, the afectada species more is river dolphin because of alterations in the rivers where they live.
It hunts to the cetáceos
The cetáceos have been objecto of to the long one of , not only for the meat and fat, but also for and for e cinereous amber of ). In middle of , was verified that many of whales was close to . Then, International commission of the Whales it decreed one moratorium for the commercial capture of whales in 1986. Although to be members of the commission, some countries, as , e ,n6aoaderiramestamorat3oria. Moreover, aborígenes of , e is equally authorized to hunt whales, even so without commercial spirit, but only for subsistence, for reasons .
Accidental capture of whales
Some of cetáceos is captured accidentally in several , especially in fishes of with net of emalhar derivational, reason why this art of fishes internationally was banished, but also, even so in lesser numbers, several you would fish of drag.
Sonar and death of whales in beaches
Some ambientalistas they have supported that sonar it harms the cetáceos seriously, especially the system of great used power for Department of Defense of . Scientists British they had suggested recently in the scientific publication Nature that the sonar can be on to the incidents of deaths of whales in beaches, had the indications of that these whales deceased would have suffered decompression (to see notice of the BBC on the article of the Nature or the article of the Nature - signature requires).
The deaths em.massa of cetáceos in beaches occur of course in some species, in such way that the frequency of these incidents and the number of dead cetáceos in this way, in accordance with registers of last the 1000 years, as much of religious writings, as more recently of scientific comments, have been used esteem the variations in the size of the populations of some species. That esteem is based on the estimated one of that the ratio enters the number of died cetáceos in beaches and the total population of each species is constant in each year. Despite the suspicion of the influence of the sonar in these incidents, that can put in estimated cause the cited one, this method of esteem continues to be used. [ 1 ].
Cetáceos in the culture
Whales in the Bible
mentions whales four times: Génesis 1:21 "and Gods created great whales"; "Porventura am I it sea or a whale, so that you set in guard against me?” (Job 7:12); "Ages equal to the whale in the seio the waters" (Ezequiel 32:2); e "As well as Jonas it was in the womb of the whale three days and three nights..." (Mateus 12:40); (translation of the King version James of the Bible).
Ironicamente, the book of Jonas 1:17 (in the King version James of the Bible and other translations) not "whale" uses the word, mentioning before to the "fish" or "great fish". This detail was used with dramatical effect for Clarence Darrow in its interrogation of the fundamentalist William Jennings Bryan in , in Scopes judgment, such as it is presented in the drama "Inherit the Wind"of Jerome Lawrence e Robert E. Lee.
hunting of whales it is the subject of one of the classics of canón literary of , Moby Dick, of Herman Melville. Melville classified the cetáceos as "a fish of I gush out with a horizontal tail", despite science having suggested another thing in the previous century. Melville recognized "the reasons because Linnaeus of good it would have grado banished the whales of the sea ", but it said that, when it presented its" friends Simeon Macey and Charley Coffin, of Nantucket [...] they had joined themselves in the opinion of that the apresntadas reasons were insufficient. Charley arrived to affirm that they were a nonsense."the book of Melville is part history of adventures, alegoria part and has left ; is essentialmente a complete summary of the knowledge of on biology, cultural ecology and meaning of cetáceos, in particular of , the species of Moby Dick.
A great atracção in the aquatic parks (oceanic) and Zoos that keep small captured cetáceos, maioritariamente dolphins. Because of its capacity of learning, these are tambem used for the military in operations in the sea.
- Whales, Dolphins and Porpoises of Mark Carwardine, published for Dorling Kindersley, 2000. ISBN 0-7513-2781-6. Introductory guide to the cetáceaos.
- Cetáceos net of Portugal - Net of Arrojamento (hindrances) of Cetáceos of Portugal
- Greenpeace - anti-whaling site
- High North Alliance - pro-whaling site
- Whale Evolution
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