English introduction to Baiji dolphin

Baiji dolphin (bái qí tún), the Baiji dolphin, has lived in the Yangtze River for about 25 million years. It is an ancient relic of the Miocene and Pliocene epochs that has survived to this day. The Baiji dolphin is a small individual member of the cetacean family. It has the smallest number of surviving dolphins among the five existing freshwater dolphins in the world (La river dolphin, Asian river dolphin, Ganges river dolphin, Indus river dolphin, and Baiji river dolphin). Due to its extremely small number, the Baiji dolphin is not only listed as a first-level protected animal in China, but also one of the 12 most endangered animals in the world. Originally belonging to the freshwater dolphin family, in the late 1970s, based on the suggestions of Chinese scientist Professor Zhou Kaiya, the Baiji family was established separately. The only species of the genus Baiji in the cetacean family Baijiidae.

The body shape of the white-tip dolphin is spindle-shaped, about 2-2.5 meters long, and its weight can reach more than 200 kilograms. The mouth is long and thin, the back is light gray or blue, and the ventral surface is pure white. The dorsal fin is shaped like a small triangle, the pectoral fin is like two palms, the tail fin is flat and bifurcated in the middle. It is good at swimming and can reach a speed of about 80 kilometers per hour. . Due to living in turbid river water for a long time, the baiji dolphin's audio and visual organs have deteriorated. Its eyes are as small as a blind man, and its ear holes are like pinholes, located behind and below its eyes. But the brain is particularly developed, the sonar system is extremely sensitive, and the head also has an ultrasonic function that can quickly transmit sounds within tens of thousands of meters on the river surface into the brain. In the event of an emergency, dive immediately to escape. Baiji dolphins are cold-tolerant, and their body temperature is usually around 36°C.

Edit this paragraph's distribution range

White-sided dolphins mainly live in the middle and lower reaches of the Yangtze River and the Dongting Lake, Poyang Lake, Qiantang River and other waters connected to it, usually in pairs or more than 10 individuals. At the same time, they like to move in places with deep water and rapid currents. The current population is rare. It was estimated that there were only about 300 animals 20 years ago. At that time, it was already in danger of extinction.

Edit this paragraph's living habits

White-sided dolphins like to live in groups, especially during the spring mating season, the swarming behavior is more obvious. Each group usually has 2-16 animals. It has a wide range of activities, but has high requirements for water temperature conditions. It often stays in a fixed area for a period of time, and then moves to another area after the water temperature conditions change. Feed on fish.

The white-tip dolphin likes to live in the deep waters of rivers and rarely gets close to the shore or boats. However, it often swims to shallow waters to chase fish and shrimp to satisfy its hunger. Its snout is wide and slender, and its upper and lower jaws have more than 130 conical teeth of the same shape. However, it is too lazy to chew. It just opens its mouth to swallow the fish food, and its digestive ability is very strong. Baiji dolphins often move together in pairs or small groups, but people rarely have the opportunity to see it. They can only catch a glimpse when it comes out of the water to breathe.

White-finned dolphins are distributed in the 1,600-kilometer stretch from Zhicheng, Hubei Province to the Yangtze Estuary in the middle and lower reaches of the Yangtze River. They feed on fish and like to move in groups. Small groups are about 2 to 3 individuals, and large groups are about 9 to 16 heads. The Baiji dolphin is an aquatic mammal that breathes with lungs. Every time it breathes, the top of its head and breathing holes surface first, and then its back and low triangular dorsal fin are exposed. It takes about 1-2 seconds to breathe out of the water, and the diving time is about 20 seconds, up to 200 seconds during long dives. The maximum body length of mature individuals is 2.5 meters for females and 2.3 meters for males. They weigh 100 to 150 kilograms. They have a constant body temperature, always around 36 degrees Celsius.

Edit this paragraph’s breeding habits

Baiji dolphins breed once every two years, with one calf per litter, and the body length is about 80 centimeters at birth. Newborn larvae are slightly darker in color. Adult Baiji dolphins are generally light blue-gray on the back and pure white on the belly, which is particularly bright under the sunlight. The upper and lower surfaces of the horizontally extending flippers and tail fin are the same color as the back and ventral surfaces respectively. This color distribution exactly matches the color of the environment. When looking down from the water surface, the blue-gray color on the back blends with the river water and is difficult to distinguish; when looking up from the bottom of the water, the white belly is similar in color to the strong light reflected from the water surface and is difficult to detect. This gives the baiji dolphin a natural hiding barrier when escaping from enemies and approaching prey. Baiji dolphins can live for more than 30 years. Females generally reach sexual maturity at 6 years old, and males at 4 years old. Adult Baiji dolphins come into estrus twice a year, from March to May and from August to October. The gestation period is 10 to 11 months, with one litter and one litter, and occasionally two litters. In the wild, the male-to-female ratio of adult baiji dolphins is 1:1, but the pregnancy rate of female animals is generally only 30%, and the natural reproduction rate is very low.

The late winter and early spring of each year is the mating period of the white-skied dolphins. The gestation period of the female dolphins lasts for about one year, so most of the calfs are born in the spring of the following year. After birth, the calf is fed by its mother's milk and does not mature until it is five or six years old; its average lifespan is 30 years.

Edit this paragraph's body structure

The white-tip dolphin is a carnivore, with about 130 sharp teeth in its mouth, all of the same type. It often swims to the shallow water of the shore to hunt at dawn and dusk. It usually devours whole freshwater fish less than 6.5 cm in length. It also eats a small amount of aquatic plants and insects. When breathing, the head comes out of the water first, and then the whole body is exposed to the water. After swimming 2 meters on the water, enter the water again. The white-tip dolphin has almost zero vision and relies on echolocation to understand environmental changes. It has extensive scientific research value in biology, bionics and physiology. However, baiji dolphins are timid by nature and are easily frightened. They generally stay away from ships and are difficult to approach. In addition, their population is small and their activity areas are vast. Therefore, research on baiji dolphins in the wild is very limited.

The skin of the baiji dolphin is smooth and delicate, and is rich in a special kind of elasticity. The principle is the same as the elastic nylon fabric used in competitive swimming suits, which can reduce the turbulence around the body when swimming quickly in the water. Its tail fin is divided flat into two forks, the pectoral fins on both sides are flat palm-shaped, and the dorsal fin is triangular. These four fins provide the baiji dolphin with excellent direction and balance control when swimming in the water. Coupled with its smooth and highly elastic skin and streamlined body, the baiji dolphin can swim at a speed of 60 kilometers per hour while escaping from danger. . It usually maintains a swimming speed of 10 to 15 kilometers per hour.

The white-tip dolphin has lived in the turbid water of the Yangtze River for a long time, so its vision and hearing have been severely degraded. It mainly uses sonar to identify objects in the water. The upper respiratory tract of the Baiji dolphin has three unique pairs of air sacs and a throat shaped like a goose head. However, because it lives in water and relies on water to make sounds, it does not have the vocal cords required by land animals to make sounds in the air. With a special hydrophone, you can hear dozens of different sounds such as the "dack" and "quack" made by the Baiji dolphin. Baiji dolphins often make two sounds in a pair. After making a sound, they will wait quietly for the echo to identify the distance and size of the obstacle that generates the echo, and to consider whether to swim towards the target. It will make a new pair of sounds shortly after receiving the echo, and then stay quiet for a while waiting for the echo. After receiving the second echo, it can analyze the direction and speed of the target's swimming. This is how the Baiji dolphin performs echolocation like artificial sonar. Using this unique sonar system, it can often catch food in the mud at the bottom of the river, and it can also emit high-frequency sound waves that are inaudible to human ears to communicate with its companions more than ten kilometers away.

The brain surface area of ??the Baiji dolphin is larger than that of the dolphin, and the weight of the brain accounts for about 0.5 of the total mass. The average brain of a male dolphin weighing 95 kilograms weighs 470 grams. This weight is close to the brain weight of gorillas and chimpanzees, and some scholars even believe that the baiji is smarter than gibbons and chimpanzees.

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, extreme

ely 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 th

an 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 Yang

tze River dolphin in the Cho-shui, its 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 percen

t 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.