Agkistrodon halys is one of the most widely distributed and numerous poisonous snakes in China, and there are many disputes about its subspecies classification. This argument lasted for more than 60 years, mainly because of the lack of sufficient evidence to convince the other side. Therefore, 560 samples of moths and snakes were compared with the data collected by Maki( 193). According to the number of scales, head shape, color spots and distribution areas, it is determined that Chinese snakes can be divided into three subspecies: intermediate subspecies, short-tailed subspecies and Japanese subspecies. Intermediates are mainly distributed in the north of Qinling Mountains, starting from Inner Mongolia in the east and reaching Xinjiang in the west. Zoogeographically, they belong to the west of Palaearctic Meng Xin Region and the sub-region of North China Loess Plateau. The short-tailed salamander is mainly distributed in the south of Qinling Mountains, and its southern boundary is about 26 north latitude, which belongs to a part of Central China and Southwest China in the Oriental world. Shanxi, Hebei, Shandong and Northeast provinces are the same distribution areas of these two subspecies. Smith (1943) extended the southern boundary of Agkistrodon halys to an island in Beibu Gulf, which was a serious mistake. The island he said is called Xiaolongshan Snake Island, which is actually a snake island, in the west of the southern tip of Liaodong Peninsula, not the west of Leizhou Peninsula. Qinling Mountain is the main watershed between the Yellow River and the Yangtze River. From Paleozoic to now, it has been playing a role in dividing the north and south of China. Therefore, in the geographical distribution of animals, it is considered as a natural barrier between Palaearctic realm and Oriental realm, which is not only effective for birds and animals, but also more effective for the distribution of snakes. However, from Funiu Mountain to the east, the eastern part of Qinling suddenly drops and borders the North China Plain. The short-tailed subspecies distributed in the south of Qinling Mountains met with the middle subspecies of Palaearctic realm through this area, forming a coextensive distribution area of the two subspecies. An obvious and interesting example is that in Shaanxi, Yangxian and Zhouzhi are very close, but separated by Taibai Mountain and shouyangshan, the main peaks of Qinling Mountains. Agkistrodon halys collected in Nanyang County, Shannan Province is a short-tailed subspecies, while Agkistrodon halys collected in Zhou Bei, Shannan Province is an intermediate subspecies, which shows that Qinling Mountain has played a geographical isolation role for these two subspecies. Japanese subspecies are only distributed in Taiwan Province Province, China, and are the same as those produced in Japanese archipelago. There are a lot of intermediaries in two places. One is located in the west of Heilongjiang, near Zhuoshan Station in Mongolia. There are six hills in the north of the station, about 3 kilometers long and one or two kilometers wide. It's a quarry of the railway bureau, and the mining of 1 ~ 3 hill was stopped because there were too many poisonous snakes. The other is Snake Island, with an area of only about 1 km2. In the past, someone (Hasegawa Hideyoshi, 1932) estimated that there were 500,000 poisonous snakes on the island, which was obviously an exaggeration. 1957 after the investigation on the island, we estimated that there were about 50,000 vipers. Recently, the scientific research team in Shedao, Liaoning Province made a survey on the number distribution on the island, and thought that there were about 20,000 existing Agkistrodon halys, which was close to our current estimate. Because of the fire and overfishing on the island after 1959, a considerable number of Agkistrodon halys were lost. Agkistrodon halys mostly live in plains, hills and mountains, and inhabit stone piles, grasslands, ditches, graves, bushes and fields. The caves of short-tailed salamander are mostly on sunny slopes, with a diameter of 1 .5 ~ 4.5cm and a depth of about1m, and most of them are old caves dug by frogs and mice. Most of the agents in Snake Island live in crevices, grass and branches, motionless, with their heads up to the sky. When the bird stopped near it, it quickly attacked the bird. There are several poisonous snakes in a small tree. There are 2 1 on the Luan tree more than two meters high and 25/on the cherry tree. When birds are scarce, they often lurk in grass and cracks. For example, there are few birds on the island from June 5438 to September 0957. Of the 4 13 Agkistrodon halys caught, 54.52% were caught in grass, 43.6 1% were caught in rocks, and only 1.87% were caught in trees. Effect of temperature on Agkistrodon halys Temperature is the main factor that determines the activity of Agkistrodon halys. The borer can move normally at 2 ~ 38℃, and the optimum temperature is 20 ~ 30℃. In Zhejiang, the lowest temperature for catching it in the wild is 9℃. In snake island, when the temperature is above 4℃, the mesothelium comes out and moves. Effect of light on Agkistrodon halys The reaction of Agkistrodon halys to light changes with temperature. Avoid light when it is hot, and turn to light when it is cold or warm. In the 12 months of the whole year, its occurrence rate at noon 12 is the lowest in July, followed by August. On the contrary, the occurrence rate of midnight is the highest in July, followed by June, indicating that its activity frequency is not only related to light, but also to temperature. Effect of Rain on Agkistrodon halys Light rain has no effect on the activities of Agkistrodon halys in Snake Island, but when the rain clears up and the weather is wet, more people climb trees. It is not so much the influence of rain as the food, because birds are most active at this time. The poisonous snake that climbs the tree will not leave because of the wind and rain. In Zhejiang, there are more trees in rainy days and after rain, but in Guizhou, there are more activities in sunny days than in rainy days, probably because Guizhou is a plateau with low temperature. Agkistrodon halys need drinking water very much, and lack of drinking water will shorten their life. The mussel in the snake island can suck dew on the petals of Dianthus northeast, and can also suck stagnant water on the ground. During the captivity, it was also observed that Agkistrodon halys often drank water. Some people (Lop, 1970) think that water is a powerful stimulus to the chemoreceptors of snakes without water. The feeding habit of Agkistrodon halys is an omnivorous species, which is an important reason for its wide distribution. They mainly feed on vertebrates, including loaches, eels, frogs, lizards, birds and mice. Some vipers found spiders in their stomachs, probably because they swallowed frogs. Viper snake island mainly eats small migratory birds. In 82 autopsies, there were 2 1 species of birds, belonging to 3 orders and 8 families, mainly arboreal species of passeriformes. Agkistrodon, which moves on the ground, also preys on quail, yellow-footed three-toed quail, thrush and other terrestrial birds, and also attacks the larger sparrow hawk, mountain dove, black pillow Huang Peng and so on, but it cannot be swallowed. The bodies and remains of these birds can often be found in Snake Island. Occasionally, I will swallow Rattus norvegicus. The newborn baby viper, with a total length of 280 ~ 330 mm, can swallow big birds such as yellow eyebrow and Ye Ying, but it mainly feeds on centipedes, long-headed centipedes and rats. It is the first time in the world that moths and snakes eat centipedes. Reproductive habit of Agkistrodon halys The sex ratio of Agkistrodon halys is 100(○ 10): 98. On the island, the mating of Agkistrodon halys can be seen in May, August, September and June in 5438+1October, both in the morning and in the afternoon. One of them was found on the branches of Phyllanthus urinaria at an altitude of 150 meters on June 6 10: 30 in 65438. It was cloudy and the temperature was 16.6℃. At first, the male snake lay on the back of the female snake, and his tail was wrapped around the branches and the tail of the female snake. Soon, the female snake finished mating, and the male snake leaned forward slightly and nodded frequently. When the male snake head approached the female snake head, the female snake slightly looked up and nodded until 10: 48. The directional behavior of Agkistrodon halys has the ability of directional activity. Throw it into the sea, and it can swim towards the island. It works every time. The investigation of Snake Island in Liaoning Province also found that Agkistrodon halys has the ability to return to its original habitat. The marked viper can return to the original branch the day after leaving the tree, waiting to catch birds. I've seen several cases where the viper was frightened and left, and soon returned to its original place. Interestingly, a poisonous snake on the yellow elm tree, 1973, got down from the tree at 4 pm on September 29, climbed up the tree from its base at 6: 45 the next day, climbed up and down, passed nine branches up and down for 53 minutes, and finally reached the original branch and stopped at its original position. 10 year 10 6, after a lapse of 6 days, he still lives in his original place. Strangely, in June of 1974, the snake was found on the original branch more than 8 months later. It can be seen that its orientation ability is strong. The venom of Agkistrodon halys and its poison, the weight of poisonous glands and the length of fangs increase with the total length, but when the total length exceeds 800 mm, it decreases. The weight of poison gland is 50 ~ 3 10 mg, with an average of 163 mg, and there is no difference between men and women. The length of fangs is 4.5 ~ 10.0 mm, with an average of 7.3 mm for females and slightly longer for males. The fangs of short-tailed Agkistrodon halys are 3.5 ~ 65 mm long, with an average of 5. 1 mm, which is much shorter than that of intermediate Agkistrodon halys because it is smaller and shorter. The detoxification amount of the bite of the intermediate Agkistrodon halys (600 mm long) is 82.4 mg, and that of the short-tailed Agkistrodon halys (645 mm long) is 50.8 mg. The amount of detoxification is not only different from subspecies, but also related to the size of snakes. For example, the total length of Agkistrodon brevicaudatus is 300 ~ 399 mm, the average dry weight of detoxification is 6.24 mg, 400 ~ 499 mm is 17.45 mg, and over 500 mm is 3 1.98 mg. Moreover, the amount of detoxification varies with the physiological state and environment of snakes. A full poisonous snake has little detoxification. About 20% of poisonous snake bites have no clinical symptoms, which is related to this. For bitten animals, warm-blooded animals are often more resistant than warm-blooded animals. For people, there are differences among individuals, and people who are sensitive to snake venom have greater toxic reactions. For poisonous snakes themselves, the main function of venom is to prey on and digest food, followed by defending natural enemies. Therefore, Porges( 1953) thinks that the biological significance of snake venom is mainly from the physiological and biochemical point of view. Viper is no exception. This is not difficult to understand, because poison glands evolved from salivary glands. Animals killed by Agkistrodon halys are prone to decay, which is related to digestive enzymes in venom, especially proteolytic enzymes. Although Agkistrodon halys has the ability to resist the same kind of snake venom, when the poison is large, symptoms of poisoning will also appear, and mutual biting or self-biting will also lead to poisoning and even death. It is strange that the bitten viper drinks a lot of water. Other poisonous snakes are also poisoned by mutual biting or self-biting.