November 14, 1998 (September 26) Tiger years, the experts said river dolphin of the rare species will be extinct in 20 years. the the



Scientific name: Lipotes THE INGESTION AND ACCUMULATION OF ZINC, COPPER (Miller, 1918) Chinese river dolphin
baiji (b��i the and j�� t��n), at the national level to protect animals, also known as white dolphin, dolphin white flag. Vertebrate door, Mammalia, Cetacea, toothed whales sub-projects. Originally the freshwater dolphin Branch, the late 1970s, according to the recommendations of the Chinese scientists, Professor Zhou Kaiya, set up a separate baiji Section. Cetacea baiji Division baiji only species of the genus. For the Chinese specialties freshwater toothed cetaceans, located in the Yangtze River middle and lower reaches. Also found in the Dongting Lake, Poyang Lake, Qiantang. Lanes are spindle-shaped, the body length of 1.5 to 2.5 meters and weigh up to 230 kilograms; were beak-like snout, narrow and long, the snout slightly upturned; frontoparietal significant uplift; eyes are small and located in the altercation below; ears minimal the shape of the eye of a needle in the eye after below; dorsal fin was low isosceles triangle, is located in the back middle slightly on; flippers wide, end obtuse, concave trailing edge of the caudal fin crescent-shaped; dorsal gray or blue-gray. underside white, the back, tail fin dorsal fin, flipper are gray or green-gray, respiratory, head first water spray ejected, the caudal fin is not water. The baiji good diving, but easily maneuver the ship's propeller wounded died. Usually paired activities. Eating fish, benthic fish can be captured with a long beak.
baiji live mainly in the middle and lower reaches of the Yangtze River and its connectivity Dongting Lake, Poyang Lake, Qiantang River and other waters, usually in pairs or more than 10 heads together, happy with the water depth at the rapid current activities. Gregarious, especially in the spring mating season, the cluster behavior is even more obvious. Group generally 2-6 head. Wide range of its activities, but the the hydrological conditions require higher, often stay in a fixed area, pending hydrological conditions change, and move into other geographical. Fish for food. Baiji two years to breed once per litter Aberdeen, about 80 cm body length at birth. Hatchling body color is slightly darker, the adult the baiji general the back pale blue-gray, the ventral was clean white and bright, especially in the sunshine. Horizontal stretch flippers and tail fins up and down both sides of the back and ventral same color, so the color distribution coincided with the environment color match. When looking down from the water, the blue-gray back and river mixed as a whole it is difficult to distinguish; similar color, white belly and surface reflected glare from the bottom to the point of view it is difficult to be found. This makes the baiji and escape predators near their prey, natural concealment barrier. The baiji a life span of 30 years, females generally in the 6-year-old to reach sexual maturity, a stallion to 4 years old. Adult baiji estrus twice per year, respectively in March to May and from August to October. Pregnancy for 10-11 months, a baby born Aberdeen, occasionally two earners. The wild state adult baiji male and female ratio is 1:1, but the the females pregnancy rate generally only 30%, the low rate of natural reproduction.
baiji carnivores, about 130 sharp teeth in the mouth, the same type of teeth. Often swim toward the shore in shallow water at dawn and dusk when prey is generally less than 6.5 cm in length to the entire swallowed body mainly freshwater fish, also eat small aquatic plants and insects. Breathing, the head of the first water, then all out of the water, swimming in the water 2 meters, reentry water. The baiji's vision is almost zero, rely on echolocation to environmental change, with a wide range of research in biology, bionics and physiology. The baiji timid and easily frightened, and generally away from the vessel, it is difficult to close, in addition to the small number of its population, the active area is broad, so in the wild state dialogue dolphin research is very limited. [1 $ dj��.c��m]
white dolphin skin smooth and delicate, full of a special kind of flexibility, the principle and competition-style swimsuits used in flexible nylon fabric can reduce fast swimming in the water body around the turbulence generated. Its tail fins flat into two fork on both sides of the palm-shaped pectoral fins were flat, triangular dorsal fin. Baiji these four fins to provide control over the direction and balance excellent swimming, plus the smooth high elasticity of the skin with a streamlined body, Lipotidae per hour in the case of escape dangerous 60 one thousand meters of swimming speed. Usually maintained swimming speed of 10-15 km per hour. (1 $ dj��.c��m and)
Lipotidae long-term survival in the Yangtze Choshui. Com) (history so it's visual and auditory serious degradation in the water main to launch sonar receiver signal object recognition. Has three unique shape of goose head airbags and a throat baiji upper respiratory tract, but because to survive in the water the pronunciation by water, and there is no land animals in the air in the pronunciation of the vocal cords. With a special hydrophone, you can hear the baiji issued "A" dozens "quack" sound. The sound of the baiji often one pair or two will sound quiet waiting for the echo, which distinguish themselves and produce echo barriers of distance and size, and considering whether to swim to the target. It will after receiving the echo soon issue a new sound, wait quiet a while waiting for the echo. After the second echo is received, it will be able to analyze the swimming direction and speed of the target, the baiji is like to do, such as man-made sonar echolocation. Unique sonar system, it is often in the silt of the river bottom to catch food, can also send high-frequency sound waves inaudible, with more than a dozen kilometers away companion. of
baiji dolphin's large brain surface area than brain weight accounted for 0.5% of the overall amount of the average a weight of 95 kg male dolphin brain weighs 470 grams. Such as the weight is close to the gorilla and chimpanzee brain weight, and even some scholars believe that the baiji is smarter than gibbons and chimpanzees.