海豚是如何睡覺的?
文章來源:未知 文章作者:enread 發布時間:2020-03-26 08:46 字體: [ ]  進入論壇
(單詞翻譯:雙擊或拖選)

海豚在很多方面都和人類很像。比如說海豚有和人類很像的特殊的呼吸系統,唯一的不同是海豚能不呼吸氧氣在水下呆很長時間。但是海豚使如何做到睡覺不溺水呢?
Since Dolphins are like human being in so many ways. For example, dolphins have a special respiratory system  just like humans. The only difference is that dolphins are able to stay underwater for a long time without breathing oxygen. But how do dolphins manage to sleep without drowning?
 
Generally, dolphins sleep with only one brain hemisphere in slow-wave sleep at a time, thus maintaining enough consciousness to breathe and to watch for possible predators1 and other threats. Earlier sleep stages can occur simultaneously2 in both hemispheres. In captivity3, dolphins seemingly enter a fully4 asleep state where both eyes are closed and there is no response to mild external stimuli5. In this case, respiration6 is automatic; a tail kick reflex keeps the blowhole above the water if necessary. Anesthetized dolphins initially7 show a tail kick reflex. Though a similar state has been observed with wild sperm8 whales, it is not known if dolphins in the wild reach this state. The Indus river dolphin has a sleep method that is different from that of other dolphin species. Living in water with strong currents and potentially dangerous floating debris9, it must swim continuously to avoid injury. As a result, this species sleeps in very short bursts which last between 4 and 60 seconds.


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1 predators 48b965855934a5395e409c1112d94f63     
n.食肉動物( predator的名詞復數 );奴役他人者(尤指在財務或性關系方面)
參考例句:
  • birds and their earthbound predators 鳥和地面上捕食它們的動物
  • The eyes of predators are highly sensitive to the slightest movement. 捕食性動物的眼睛能感覺到最細小的動靜。 來自《簡明英漢詞典》
2 simultaneously 4iBz1o     
adv.同時發生地,同時進行地
參考例句:
  • The radar beam can track a number of targets almost simultaneously.雷達波幾乎可以同時追著多個目標。
  • The Windows allow a computer user to execute multiple programs simultaneously.Windows允許計算機用戶同時運行多個程序。
3 captivity qrJzv     
n.囚禁;被俘;束縛
參考例句:
  • A zoo is a place where live animals are kept in captivity for the public to see.動物園是圈養動物以供公眾觀看的場所。
  • He was held in captivity for three years.他被囚禁叁年。
4 fully Gfuzd     
adv.完全地,全部地,徹底地;充分地
參考例句:
  • The doctor asked me to breathe in,then to breathe out fully.醫生讓我先吸氣,然后全部呼出。
  • They soon became fully integrated into the local community.他們很快就完全融入了當地人的圈子。
5 stimuli luBwM     
n.刺激(物)
參考例句:
  • It is necessary to curtail or alter normally coexisting stimuli.必需消除或改變正常時并存的刺激。
  • My sweat glands also respond to emotional stimuli.我的汗腺對情緒刺激也能產生反應。
6 respiration us7yt     
n.呼吸作用;一次呼吸;植物光合作用
參考例句:
  • They tried artificial respiration but it was of no avail.他們試做人工呼吸,可是無效。
  • They made frequent checks on his respiration,pulse and blood.他們經常檢查他的呼吸、脈搏和血液。
7 initially 273xZ     
adv.最初,開始
參考例句:
  • The ban was initially opposed by the US.這一禁令首先遭到美國的反對。
  • Feathers initially developed from insect scales.羽毛最初由昆蟲的翅瓣演化而來。
8 sperm jFOzO     
n.精子,精液
參考例句:
  • Only one sperm fertilises an egg.只有一個精子使卵子受精。
  • In human reproduction,one female egg is usually fertilized by one sperm.在人體生殖過程中,一個精子使一個卵子受精。
9 debris debris     
n.瓦礫堆,廢墟,碎片
參考例句:
  • After the bombing there was a lot of debris everywhere.轟炸之后到處瓦礫成堆。
  • Bacteria sticks to food debris in the teeth,causing decay.細菌附著在牙縫中的食物殘渣上,導致蛀牙。
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TAG標簽: 英語科普 睡覺 海豚
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