Why does the giant salamander cry like a child?

The giant salamander is a rare animal unique to China, which is only distributed in some rivers in China. It is also called "giant salamander" because its cry is like a child crying.

The giant salamander is the largest amphibian in existence. Generally, it is .6-.7 meters long, and the largest can reach 1.8 -2 meters, weighing 2-25 kilograms. It looks very strange, with a large flat head, a large mouth, but small eyes and nostrils, and a large tail with a flat side behind it. The whole body is smooth, without scales, four legs are short and fat, and the front legs are like baby's arms.

The giant salamander lives in streams with clear water, low water temperature and many deep pools at an altitude of 1,2-1,3 meters, and lives in caves and crevices. The caves are spacious and flat. When swimming, the limbs cling to the abdomen and move forward by swinging the tail and body to pat the water. It also has the ability to climb trees with its limbs. Because the eyes are afraid of light, they sleep during the day and come out for activities and foraging at night. They mainly feed on fish, shrimp, crabs, insects, snakes and frogs. It generally does not take the initiative to attack when foraging, but waits for the food to be delivered to the door. Its teeth can't be chewed. After food is swallowed, it can be digested slowly in the stomach. It is very resistant to hunger. It can survive without eating for several months, and hibernate like a frog in winter.

giant salamanders usually breed in June-August. Female giant salamanders lay their eggs in caves and attach them to rocks in slow-flowing places, each time they can lay hundreds of eggs, and after 21 days, the eggs naturally hatch into larvae. Larvae grows very slowly, reaching .2m long and weighing less than 1g after 3 years.

The giant salamander has been hunted by people for a long time. Although it has been listed as a national second-class protected animal, poaching still occurs. At present, the number of giant salamanders is very rare, and in some places, giant salamanders have even disappeared.

The giant salamander is the largest and most precious amphibian in the world. Its cry is very similar to that of children, so people call it "giant salamander", which is a national second-class protected aquatic wild animal and a key development variety of agricultural industrialization and characteristic agriculture. It is a genetically protected species of wild animals

Chinese name: giant salamander

Latin scientific name: Andrias davidianus

common name: giant salamander, mermaid, baby fish, pike, foot fish, crow fish, Taxonomic status of la dog

: Fauna in animal kingdom → Chordata in CHORDATA → Vertebrata in Vertebrata → Amphibia in Amphibia → Caudata in Cauda → Cryptobranchoidea in Cryptobrachidae → Andrias in Andrias. → Andrias davidianus

National key protected animal level: level II

IUCN: to be determined (I)

Endemic species: yes

endangered level: endangered

Protection measures: artificial breeding, national level, existing protected areas

. Recently, scientists have studied that the giant salamander breathes through its gills when it is a child, and breathes through its lungs when it grows up. The giant salamander lives in streams in mountainous areas, and lives in caves with clear water quality, low sediment concentration, rapid water flow and backwater. The giant salamander has a flat and blunt head, a large mouth, underdeveloped eyes and no eyelids. The front part of the body is flat, and gradually turns to lateral flat at the tail. There are obvious skin folds on both sides of the body, the limbs are short and flat, and the fingers and toes are slightly webbed. The tail is round with fins above and below it. The body color of giant salamander can change with different environment, but it is generally grayish brown. The body surface is smooth and scaleless, but there are various stripes and mucus. The ventral color of the body is light

The giant salamander is fierce and carnivorous, and feeds on aquatic insects, fish, crabs, shrimps, frogs, snakes, turtles, rats and birds. The predation mode is "waiting for the rabbit". The giant salamander usually lives in the crevices of the mountain stream, and the cave is below the water surface. At night, it stays quietly in the stone pile at the beach mouth. Once it finds the prey passing by, it makes a sudden attack. Because the teeth in its mouth are sharp and dense, it is difficult for the prey to escape after entering its mouth. Its teeth can't be chewed, just open its mouth and swallow the food, and then slowly digest it in the stomach. Giant salamander has a strong hunger tolerance, and it will not starve to death if it is kept in cool water for two or three years without eating. It can also overeat, and a full meal can increase one-fifth of its weight. When food is scarce, there will be cannibalism, even feeding on eggs

Chinese giant salamander is distributed in all provinces and regions except Xinjiang, Tibet, Inner Mongolia, Jilin and Taiwan Province, mainly in the mountains and streams of the middle and upper reaches of the Yangtze River, Yellow River and Pearl River.

The natural distribution of the origin of Chinese giant salamander is mainly concentrated in four regions in China: First, Zhangjiajie, Jiangyong, Yueyang and Xiangxi Autonomous Prefecture in Hunan; The second is Fangxian and Shennongjia in Hubei; The third is Ankang, Hanzhong and Shangluo in Shaanxi; The fourth is Zunyi, Guizhou, Yibin, Wenxing and other places in Sichuan. Others are scattered in Hefeng, Enshi, Hubei, Jing 'an, Jiangxi, Liuzhou, Yulin, Wenxian, Gansu, Lushi, Haoxian, Henan, and Qiandongnan, Guizhou. Among them, Yanxiang in Guiding County, Guiyang, Guizhou has become the "hometown of giant salamander in China". According to statistics, there are about 9, giant salamander natural resources, most of which are in hilly and mountainous areas, and the resources are even more insufficient in economically developed areas due to the intensification of industrial pollution. Female salamanders lay eggs from July to August every year, and the eggs are laid in rock caves, with more than 3 eggs per tail, and the rest of the rearing tasks are handed over to male salamanders. Male salamanders bend their bodies into a semicircle and surround their eggs to avoid being washed away by water or being harmed by enemies. They hatch young salamanders after 2-3 weeks, and after 15-4 days, the little "giant salamanders" disperse their lives before the male salamanders are willing to leave. The life span of giant salamander is also the longest among amphibians. Under the condition of artificial feeding, it can live for 13 years. Because of its tender meat and fresh taste, it has been hunted by people for a long time. The number of producing areas has dropped sharply, and some producing areas are on the verge of extinction. At present, the reality is that the giant salamander is a precious wild resource, mainly because of human factors, especially the loss of living environment, habitat destruction and over-utilization, which have caused a serious threat to the survival of giant salamander, resulting in a sharp decline in population and a doubling of its distribution area, and it is in an endangered state.

China has a vast territory, complex landforms, numerous rivers and lakes, and diverse climate, which provides superior natural conditions for the formation and development of various organisms and ecosystem types, thus becoming one of the countries with the richest biodiversity in the world. China's ecosystem mainly includes six types: forest, grassland, desert, farmland, wetland and ocean. Among them, forest is the most important terrestrial ecosystem, which contains a large number of biological species and is the most diverse ecosystem type. There are many kinds of forests with complete functions in China, which have a particularly important impact on the environment and climate in China and even the whole world. Forests in China are distributed from north to south according to climatic zones, including cold temperate coniferous forests, temperate coniferous and broad-leaved mixed forests, warm temperate deciduous forests and coniferous forests, and subtropical evergreen broad-leaved forests.

the wild resources of Chinese giant salamander. Some people estimate that the total stock in China is 5,, and the real wild giant salamander may not reach 5, in nature. Of course, the more realistic number needs to be evaluated by in-depth investigation and study. Artificial breeding of giant salamanders The annual breeding volume in China is reported to be 1,, and now the artificial breeding has exceeded 2,.

We should attach great importance to saving and protecting the germplasm resources of giant salamander, because only when there is "planting" can there be seedlings, otherwise, it will become passive water and trees without roots. That is to say, the breeding of giant salamander seed should first start from the source of germplasm resources, and quickly establish a Chinese giant salamander germplasm resource bank and a Chinese giant salamander original seed breeding base to completely solve the "provenance" problem of giant salamander seed breeding.

the first giant salamander ecological park in China started construction recently in sanzhaolun national demonstration forest park in Jing' an county, Yichun city, Jiangxi province. With a total investment of 15 million yuan and an area of 8 hectares, this project is a key construction project of the Ministry of Agriculture.

the first phase of this project will be completed in October this year, which can form the capacity of breeding 5, giant salamanders and rescuing 1, giant salamanders every year. The ecological park integrates the protection of giant salamander resources, breeding and viewing, tourism and leisure, cultural exchange and development and utilization, and has set a precedent for the comprehensive protection, development and utilization of giant salamander resources in China.

Jing' an County, Yichun City, Jiangxi Province, is the main producing area of Chinese giant salamander resources and the unique "hometown of giant salamander in China". The county was the first in the country to issue a notice to protect giant salamanders, the first to set up a giant salamander nature reserve, the first to set up a special giant salamander research institute, and the first to artificially breed the first, second and third generations of giant salamanders. In 21, Jing 'an designated the giant salamander as the county mascot to be protected.

The heart structure of giant salamander is special, and some reptilian characteristics have appeared, which is of great research value.

Chinese giant salamander is a second-class protected animal, which has high economic value and wide development and utilization prospects in food, health care, medicine and appreciation, so it has attracted much attention from all walks of life.

The giant salamander is a traditional precious medicinal animal. Modern clinical observation shows that giant salamander has the effects of nourishing yin and tonifying kidney, enriching blood and promoting qi circulation, and has remarkable curative effects on anemia, cholera and malaria. At the same time, giant salamander is also an economic animal with high edible value, with tender meat, unique flavor and high nutritional value. Its meat protein contains 17 kinds of amino acids, 8 of which are essential for human body.

1. Design and construction of giant salamander culture pond

Giant salamander lives in mountain streams at an altitude of 3-8 m, and has the characteristics of liking shade and being afraid of wind, being quiet and being afraid of shock, being clean and being afraid of dirt. Therefore, it is best to build artificial giant salamander culture pond by imitating the living conditions of giant salamander in nature.

1.1 requirements for selection of farm site

1.1.1 requirements for water resources

According to the analysis results of water samples collected by our institute for many years, the overall requirements for water for giant salamander breeding are: sufficient water sources, non-toxic and harmless, and meeting the standards for fishery water use. Specifically, in terms of water source, it is better to use clear, cool and flowing water such as mountain stream water, reservoir water and groundwater, so that irrigation and drainage can be done freely; The water temperature should be strictly controlled within ~ 28℃, preferably 1 ~ 22℃. In terms of water quality, it is required to be rich in dissolved oxygen, above 3.5 mg/L, and the PH value is 6.5 ~ 7.5. The total hardness, total alkalinity, chloride, sulfate, silicate and ammonia nitrogen in the water can not exceed the fishery water standard.

1.1.2 environmental requirements

the environment around the aquaculture pond should be quiet, cool and fresh, surrounded by mountains, lush trees, sparsely populated and relatively independent. In addition, the transportation is convenient, and the local fish, shrimps, crabs or animal offal are rich in bait resources.

1.2 Design and construction of the farm

The growth of giant salamander has obvious stages and metamorphosis process, so the breeding pond for artificially breeding giant salamander should be designed and constructed in stages. The area of its culture pond should depend on the size of the giant salamander, with .5 ~ 1m2 for the juvenile giant salamander (within 1 year of tadpole stage), 1 ~ 2m2 for the juvenile giant salamander (1 ~ 2 years of juvenile giant salamander) and 2 ~ 4m2 for the adult giant salamander (2 ~ 4 years of adult giant salamander). The shape of the giant salamander culture ponds in each stage is preferably rectangular or oval, and the length-width ratio is 3: 2. Its height is required to be two to three times of the total length of the giant salamander. The periphery and bottom of the culture pond should be smooth, and the top should be equipped with escape prevention facilities or covered with escape prevention nets. Multiple caves can be designed in the pond to facilitate the giant salamander to hide, and independent irrigation and drainage facilities should be built in each culture pond to ensure that the water level can be effectively adjusted. The whole farm should establish perfect facilities to prevent the giant salamander from escaping, stealing and harming.

2. Rearing and seedling identification of giant salamander

2.1 Disinfection of breeding ponds

Newly-built breeding ponds, especially cement ponds, must be soaked for more than two months, and fry can only be released after its alkalinity disappears. For the original culture pond, disinfection drugs generally use 1PPM bleaching powder or .5PPM 9% crystal trichlorfon to kill harmful organisms such as bacteria or parasites, and then rinse with clean water and inject fresh water before stocking the fry.

2.2 sterilization of the giant salamander species

In order to prevent the giant salamander species from bringing pathogenic microorganisms into the culture pond, all the stocked giant salamander species should be soaked in water with .2g or .5g of methylene per cubic meter of water for 5 minutes, and then the liquid medicine and the giant salamander species should be gently put into the culture pond.

2.3 seedling identification

2.3.1 difference between giant salamander seedling and other seedlings

in amphibians. In the order Uradae, the species of Hynobiidae, Hylobonidae and so on are very similar to those of the giant salamander. The main difference between them is the comparison of their morphological characteristics, which mainly includes the following three points: Hylobiidae, Hylobiidae and Hylobiidae. High-quality giant salamander fry should be healthy, muscular, with no scars and parasites on the body surface, and intact external gills before metamorphosis. On the other hand, it is inferior giant seedlings.

2.4 stocking density

the stocking density of giant salamander culture pond depends on the specifications of giant salamander culture, water source, water body, bait and other factors. Under normal circumstances, it is considered that giant salamander has a small range of activities, weak feeding ability and a relatively large stocking density in the seedling stage, which is convenient for centralized management and feeding. In the adult stage, the giant salamander has a large range of activities, strong feeding ability and mutual aggression, so its stocking density should be small. According to our years' breeding practice, the stocking density is 6 ~ 1 fish/m2 in the seedling stage and 5 ~ 2 fish/m2 in the adult stage. When stocking, the specifications should be kept as neat as possible, and the difference between individuals should not be more than .5 times.

3, aquaculture management

3.1 Feeding bait

Fresh fish, shrimp, crab, frog and animal viscera are the best bait for giant salamander, and the feeding bait should be "four fixed", that is, "timing, positioning, quality and quantity", just like feeding bait for fish culture. At regular intervals, according to the activity status of giant salamanders, feeding is mostly carried out in the evening; Positioning, the bait should be placed near the giant salamander cave to facilitate the lazy giant salamander to feed; Qualitative determination, the giant salamander has strict requirements on the quality of the bait, and the variety of the bait should not be changed too much to avoid the giant salamander refusing to eat; Quantitatively, the giant salamander is gluttonous, and the feeding amount should be from less to more, step by step, generally 1 ~ 15% of the body weight, and the specific feeding should be appropriately adjusted according to the water temperature, weather conditions, giant salamander individuals and so on. In addition, when feeding the giant salamander bait, we should try our best to keep the giant salamander from being frightened and avoid spitting.

3.2 regulating water quality

the water quality in the giant salamander pond should always be kept fresh and pollution-free, with high transparency and dissolved oxygen, and the PH value is between 6.8 and 7.8. In the actual breeding process, it is necessary to remove residual bait and excrement in time, adjust the water quality with quicklime regularly, and keep the pool water flowing for a long time.

3.3 Adjust the water temperature and light

The giant salamander has strict requirements on the water temperature. If it exceeds its tolerance, it will cause the giant salamander to hibernate or sleep in summer. In hot summer and cold winter, measures must be taken to reduce or increase the temperature to ensure that the giant salamander has a suitable water temperature growth environment. In addition, the giant salamander is photophobic and raises.