白鳍豚英文简介

　　白鳍豚（bái qí tún），在长江里大约生活了2500万年的白暨豚，是中新世及上新世延存至今的古老孑遗生物。白暨豚是鲸类家族中小个体成员，是世界上现有5种淡水豚(拉河豚、亚河豚、恒河豚、印河豚、白暨豚)中存活头数最少的一种。由于数量奇少，白暨豚不仅被列为中国一级保护动物，也是世界12种最濒危动物之一。原属淡水豚科，20世纪70年代末，根据中国科学家周开亚教授的建议，单独设立了白暨豚科。 鲸目白暨豚科白暨豚属的唯一种。

　　白鳍豚的体形呈纺锤形，身长约2-2.5米左右，体重可达200千克以上。嘴部又长又细，背呈浅灰色或蓝色，腹面为纯白色，背鳍形如一个小三角，胸鳍宛如两只手掌，尾鳍扁平，中间分叉，善于游水，时速可达80千米左右。由于长期生活在浑浊的江水中，白暨豚的视听器官已经退化。它眼小如瞎子，耳孔似针眼，位于双眼后下方。但大脑特别发达，声纳系统极为灵敏，头部还有一种超声波功能，能将江面上几万米范围内的声响迅速传入脑中。一旦遇上紧急情况，便立刻潜水躲避。白暨豚耐寒，体温通常在36℃左右。
　　编辑本段分布范围
　　白鳍豚主要生活在长江中下游及与其连通的洞庭湖、鄱阳湖、钱塘江等水域中，通常成对或10余头在一起，喜在水深流急处活动。现有数量稀少，20年前的估计只有300头左右，当时就已面临灭绝的危险。
　　编辑本段生活习性
　　白鳍豚喜欢群居，尤其在春天交配季节，集群行为就更明显。每群一般2-16头。其活动范围广，但对水温条件要求较高，经常在一个固定区域停留一段时间，待水温条件发生改变后，又迁入另一地域。以鱼类为食。
　　白鳍豚喜欢生活在江河的深水区，很少靠近岸边和船只，但它时常游弋至浅水区，追逐鱼虾充饥。它的吻宽细长，上下颌长有130多枚圆锥形的同型齿，可它却懒得咀嚼，只管张口吞下鱼食，消化能力很强。白暨豚往往成对或三五成群一起活动，但人们很少有机会看到它，只有在它露出水面呼吸时才能瞥见一眼。
　　白鳍豚分布在长江中下游干流的湖北枝城至长江口约1600千米的江段内，以鱼为食，喜结群活动，小群约2～3头，大群约9～16头。白暨豚是用肺呼吸的水生哺乳动物，每次呼吸时，头顶及呼吸孔先浮出水面，接着露出背部和低三角形的背鳍，出水呼吸时间约1-2秒钟，潜水时间每次约20秒，长潜时可达200秒。成熟个体最大体长，雌性2.5米，雄性2.3米，体重100～150千克，有恒定体温，总是在36摄氏度左右。
　　编辑本段繁殖习性
　　白鳍豚两年繁殖一次，每胎1仔，出生时体长80厘米左右。新生幼体体色略深.成年白暨豚一般背面呈浅青灰色，腹面呈洁白色，在阳光的照耀下尤其光亮。水平伸展的鳍肢和尾鳍上下两面分别与背面和腹面同色，这样的颜色分布恰好与环境颜色相符。当由水面向下看时，背部的青灰色和江水混为一体很难分辨；当由水底向上看时，白色的腹部和水面反射的强光颜色相近也很难被发现。这使得白鳍豚在逃避敌害、接近猎物时，有了天然的隐蔽屏障。白暨豚寿命可达30多年，雌兽一般在6岁达到性成熟，雄兽为4岁。成年白暨豚每年发情两次，分别在3月至5月，8月至10月。孕期为10至11个月，一胎一仔，偶有两仔。野生状态下，成年白鳍豚雌雄比例为1：1，但雌兽怀孕率一般仅为30％，自然繁殖率很低。
　　每年的冬末春初是白鳍豚的交配期，母豚妊娠期长达1年左右，因此产仔大多在来年的春季。出生后的小白鳍豚靠母亲的乳汁喂养，直到五六岁才算成熟；一般寿命30年。
　　编辑本段身体结构
　　白鳍豚是食肉动物，口中约有130个尖锐牙齿，为同型齿。常在晨昏时游向岸边浅水处进行捕食，一般以整条吞食体长小于6.5厘米的淡水鱼类为主，也吃少量的水生植物和昆虫。呼吸时，头部先出水，然后全部露出水面，在水面游动2米后，再入水中。白鳍豚的视力几乎为零，依靠回声定位了解环境变化的情况，在生物学、仿生学和生理学等方面具有广泛的科研价值。但白鳍豚生性胆小，很容易受到惊吓，一般都远离船只，很难接近，加之其种群数量很少，活动区域广阔，所以在野生状态下对白鳍豚的研究十分有限。
　　白鳍豚皮肤光滑细腻，富有一种特殊的弹性，原理与竞赛式游泳衣着中使用具有弹性的尼龙织料相同，能够减少在水中快速游动时身躯周围产生的湍流。它的尾鳍扁平地分为两叉，两边的胸鳍呈扁平的手掌状，背鳍呈三角形。这四鳍给白鳍豚提供了优良的水中游动时方向与平衡的控制力，再加上光滑高弹性的皮肤与流线型的身躯，白鳍豚在逃避危险的情况下可达每小时60千米的游速。平常它保持着每小时10至15千米的游速。
　　白鳍豚长期生存于长江的浊水中，所以它的视觉和听觉均退化严重，在水中主要以发射声纳接收信号来识别物体。白暨豚的上呼吸道有着三对独特的气囊与一个形似鹅头的喉咙，但是因为生存于水中靠水发音，所以并没有陆地动物在空气中发音所需要的声带。用特制的水听器，可以听到白暨豚发出的“的答”“嘎嘎”等数十种不同的声音。白暨豚发出的声音常为两声一对，发出声音后会安静的等待着回声，从而辨出自己与产生回声的阻碍的距离和大小，并且考虑是否游向目标。它又会在收到回声后的不久发出新的一对声音，稍候又安静一阵等待回声。第二次回声收到后，它便可以分析出目标游动的方向与速度，白暨豚就是这样如人造声纳般的做回声定位。用这独特的声纳系统，它时常还可以在江底的淤泥中捕捉食物，也可以发出人耳听不见的高频率音波，与十多千米外的同伴联系。
　　白暨豚的大脑表面积要比海豚的大，大脑的重量约占总体量的0.5%，其中平均一只重95千克的雄豚，大脑重470克。这等重量已接近大猩猩与黑猩猩的大脑重量，甚至某些学者认为白暨豚比长臂猿和黑猩猩更聪明。

　　Dolphin (bái qí tún), about living in the Yangtze River in the years 2500 and the white dolphin, is the Miocene and Pliocene extension has kept the ancient relict biological. White whales and dolphins are small and medium-sized individual family members, is the world's available fresh water dolphin 5 (La globefish, Asia globefish, Platanistidae India globefish, and the white dolphin), the first to survive for at least a few. As the number of odd little white dolphin and not only China is listed as a protected species, the world's 12 most endangered animals. River dolphin origin, age 70 at the end of the 20th century, according to Chinese scientists, Professor Zhou Kaiya's proposal to set up a separate white dolphin and Branch. Mejiro whale and dolphin and the white section is the only species of dolphin.

　　The dolphin was spindle shape, is about 2-2.5 meters and weighing up to 200 kg and above. Long and thin mouth, back Light gray or blue, pure white for the ventral, dorsal fin-shaped as a triangle, two pectoral fin like the palm of your hand, flat tail fin in the middle fork, good at swimming, the maximum speed of 80 km around . Due to the long-term living in the muddy river, the white dolphin and audio-visual organs have been degraded. Small as it is blind eye, the eye of a needle like ears, eyes at the bottom of the post. However, the brain developed, thus, extremely sensitive sonar system, there is a head ultrasound function, Jiang could face tens of thousands of meters of the rapid introduction of sound mind. In the event of an emergency, they immediately dive to escape. White dolphin and cold, the temperature is usually around 36 ℃.
　　Edit this paragraph distribution
　　The main dolphin living in the middle and lower reaches of the Yangtze River and Dongting Lake and its connected, Poyang Lake, Qiantang River waters, etc., usually in pairs or more than 10 heads together and happy with the current depth of radical activities of the Department. Scarce number of available 20 years ago, estimates that only about 300, at the time was facing extinction.
　　Edit this paragraph living habits
　　Dolphin like gregarious, especially in the spring mating season, is even more obvious acts of the cluster. Each group of 2-16 in the first general. Its wide range of activities, but the higher water temperature conditions, often in the region remain a fixed period of time, the water temperature conditions to be changed, and moved to another area. To fish for food.
　　Like the river dolphin living in the Sham Shui Po District, near the shore and small boats, but it is always around to shallow waters, chasing fish to eat. Its wide kiss slender, long upper and lower 130 more than the same type of conical teeth, it may be too lazy to chew, just swallow the mouth fresh fish, a strong ability to digest. White dolphin and often in pairs or small groups together, but rarely have the chance to see it, it only exposed the surface to breathe in order to catch a glimpse of a time.
　　Dolphin in the middle and lower reaches of the Yangtze River in Hubei Zhicheng to the main stream of the Yangtze River estuary, about 1600 kilometers of the river, to fish for food, hi clustering, a small group of about 2 to 3, the crowd of about 9 to 16. White dolphin is a lung and respiratory aquatic mammals, each breath, his head and breathing surface first hole, then his lower back and dorsal fin of the triangle, the water to breathe for about 1-2 seconds, each time diving around 20 seconds, the long latency of up to 200 seconds. The most mature individual body length, 2.5 m female, male 2.3 meters and weighing 100 to 150 kilograms, there is a constant body temperature, always around 36 degrees Celsius.
　　Edit this paragraph breeding habits
　　Dolphin breeding first two years, Aberdeen 1 per child, born about 80 cm length. Newborn larvae deep color slightly. Dolphin and the general adult white on the back of Green Light gray, white ventral was clean, the sun's shining especially bright. The level of the extended flipper and tail up and down with both sides of the same color on the back and ventral, so that the distribution of color exactly match the color and the environment. When looking down from the surface, the back of the green and gray of the river is mixing it is difficult to distinguish; from the bottom to the point of view when, a white belly and the light reflected from the surface color is also similar to those found to be very difficult. This allows the dolphin to avoid Di Hai, close to the game, with the hidden natural barriers. White dolphin and up to 30 years of life, in general Cishou 6-year-old to reach sexual maturity, Xiongshou 4-year-old. Adult white dolphin and estrus twice a year, in March to May and August to October. Pregnancy for 10-11 months, a one-child class, sometimes two earners. Wild state, an adult male and female ratio of 1:1 dolphin, but Cishou pregnancy rate was only 30% of the normal, natural reproduction rate is very low.
　　Dongmochunchu annual dolphin is the mating season, the mother dolphin pregnancy for up to 1 year or so, so most of the litter in the spring of next year. After the birth of small dolphin feeding by the mother's milk until five or six-year-old is mature; general life expectancy of 30 years.
　　Editor of the physical structure of the paragraph
　　Dolphin is predators, population about 130 sharp teeth, tooth for the same type. Often in the twilight tour shore shallows when Predation for the general to swallow the entire length of less than 6.5 cm of fresh water fish-based, but also eat small amounts of aquatic plants and insects. Breathe, the water head first, and then exposed all of the water, swimming in the water 2 meters, the water re-entry. Dolphin's vision is almost zero, to rely on echolocation to understand environmental changes in biology, physiology and bionics, and so on a wide range of scientific research value. But the dolphin timid nature, are susceptible to shock, usually away from the vessel, it is difficult to close, combined with its small population, vast regional activities, so in a state of wild dolphin research is very limited.
　　Dolphin skin smooth and delicate, full of a special kind of flexibility with the principle of competition-style bathing suit with the use of flexible nylon weave the same material, to reduce the fast swimming in the water when the turbulence generated around the body. Its flat tail fin to be divided into two forks, on both sides of the pectoral fin was like the palm of your hand flat, triangular dorsal fin. This four-fin dolphin to provide excellent swimming in the water when the direction of balance and control, combined with high flexibility of the skin smooth and streamlined body, the dolphin to avoid dangerous situations, up to 60 km per hour speed of travel . It usually maintains a 10-15 km per hour, the travel speed.
　　Long-term survival of the Yangtze River dolphin in the Cho-shui, it's visual and hearing are severely degraded, the water in the main reception to launch sonar signals to identify objects. White dolphin and the upper respiratory tract has three unique shape of a balloon with a goose head of the throat, but to survive in the water by water sounds, and there is no land animal in the air pronunciation of the vocal cords needed. With a special hydrophone, you can hear the white dolphin and issued "A" "quack" and dozens of different voices. White dolphin and the voice of regular twice for a pair of issuing a quiet voice will be waiting for the echo, which detected the echo of their own and have hindered the distance and size, and to consider whether travel to the goal. It will echo the receipt issued shortly after a pair of new voices, and wait quietly for a while waiting for the echo. The second received echo, it will be able to analyze the goal of swimming in the direction and speed, and white dolphin is one such man-made, such as sonar-like echolocation to do. This unique use of the sonar system, which can from time to time in the mud at the end of Jiang's capture in food, can not issue a human face value of the high-frequency sound waves, with more than 10 km outside the peer contact.
　　White dolphin and the surface area of the brain than the dolphin, the weight of the brain accounts for about 0.5 percent of overall volume, of which an average weight 95 kg male dolphin, brain weight 470 grams. This is close to the weight of gorilla and chimpanzee brain weight, and even some scholars believe that white dolphins and chimpanzees and gibbons than smarter.

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