第1个回答 2020-12-31
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.