Problem description:
Crocodile turtle is a rare turtle, which looks like a turtle and a crocodile.
Analysis:
Crocodile turtles are divided into big crocodiles and small crocodiles. The big crocodile is also called the convex-backed crocodile, and the small crocodile is also called the flat-backed crocodile. Small crocodiles are divided into four subspecies. The main difference between a big snapping turtle and a small snapping turtle is that its back shield is protruding. With the increase of age, the big snapping turtle is always more obvious, while the young snapping turtle is more obvious in its infancy, but less so in its adult stage. Crocodile turtles originated in North America and so on. , and introduced to China from 1996. They look strange. Their tail spines are particularly like crocodiles. In terms of growth rate, snapping turtles grow slowly when they are young, and grow faster when they reach 250 grams. Under the condition of artificial temperature control, it only takes 1 year to grow from 250 grams to 2500 grams, and the largest individual in nature reaches 100 kilograms. Small snapping turtles grow slowly below 50g, and it takes about 80 days to grow from 7g to 50g. Under the condition of temperature control, it takes only 1 year for a 50-gram snapping turtle to grow to 2500 grams or a 7-gram snapping turtle to grow to 1.500 grams. In the natural state, small snapping turtles can grow to more than 23 kilograms. The difference in growth speed between the big snapping turtle and the small snapping turtle is mainly caused by different habits. The snapping turtle is lazy and not good at taking the initiative to eat. It lures small fish with its earthworm-like "tongue". Small snapping turtles can take the initiative to eat, and naturally grow faster than big snapping turtles. Therefore, China breeds more small snapping turtles than big snapping turtles.
1 Biological characteristics of snapping turtles
Classification status of 1. 1
Crocodile turtles belong to Chordata, Vertebrate, Reptilia, Tortoise, Tortoise and Tortoise. The scientific name of snapping turtle is Macroclemys, and the English name is Alligator snapping turtle. ; The scientific name of the little snapping turtle is Chelydra Serpentina sap. The English name is common snapping turtle. The four subspecies of the small snapping turtle are: 1) Acutirostis South American snapping turtle, also known as fake snapping turtle; 2) osceola Florida snapping turtle, which can grow to 17 inch and weigh 45 pounds; 3)rossignonii Chinese and American snapping turtles, also known as snapping turtles; 4)serpentina North American snapping turtle, also known as kowtowing turtle.
1.2 country of origin
Mainly distributed in North and Central America, especially in the southeastern United States. Miami is an important origin of snapping turtles. Crocodile turtles in the United States are called "South Tortoise" and "North Tortoise" because of their different distribution areas. Their body colors are divided into "yellow back" and "black back". Yellow-backed snapping turtle is resistant to high temperature, while black-backed snapping turtle is resistant to low temperature. China mainly imports from Florida. Except for a few crocodiles, most of them are small crocodiles. Currently distributed in Beijing, Shanghai, Jiangsu, Zhejiang, Jiangxi, Hainan, Guangdong, Guangxi, Hunan, Shandong, Sichuan and other places.
1.3 Suitable temperature range
Normal living is at 2℃~38℃, normal overwintering is above 1℃, shallow hibernation is below 12℃, deep hibernation is at 6℃, a little activity is at 15℃~ 17℃, and normal feeding is at 18℃.
1.4 body type and maximum record
The snapping turtle has a primary size of 8~ 10g, a general adult size of 6 1~76cm, 77~9 1kg, and the maximum recorded size is 79cm and 107kg (Brookfield Zoo, Chicago, USA). The average shell length of young snapping turtles is 3.3cm and their weight is 7.2g (minimum 3. 1cm, 5.8g and maximum 3.7cm, 14.8g), while the average shell length of adult snapping turtles is 3 1~46cm and their weight is 23~36kg. In nature, the largest individual can reach more than 38 kilograms. Different from ordinary turtle eggs (oval), small crocodile turtle eggs are spherical and white, with a diameter of 23~33mm and an egg weight of 7~ 15g.
1.5 shape features,
The upper jaw of snapping turtle looks like an eagle's beak and has a big hook. It has many tentacles on its head, neck and abdomen. Its shell has three raised longitudinal ridges, which are brown. Each shield has a protrusion, a brown belly, a shield on the top and a long tail. It has a wormlike appendage at the bottom of its mouth. It often lies in the water with its mouth open and uses it to lure nearby fish.
The upper jaw of a small snapping turtle looks like a hook, but the hook is very small, with only a few tentacles. The back nail is brown or dark brown with three longitudinal ridges. The rib shield is slightly raised, and the ridge gradually wears away with time. The upper abdomen is gray, without edge shield, and the tail is slightly shorter. The most striking feature is that there is a serrated ridge on the back of the tail, also called the tail spine.
1.6 Gender differences
The female carapace of snapping turtle is square, the tail base is thin, the reproductive hole is close to the rear edge of the carapace, the male carapace is rectangular, the tail base is thick and long, and the reproductive hole is far from the rear edge of the carapace.
In addition to the above characteristics, the female is located in or flush with the first hard spine of the tail, while the male is located outside the first hard spine of the tail.
1.7 Living habits
The basic habits of big snapping turtles and small snapping turtles are similar. Usually it is not easy to fight in water, but it can be rushed and bitten on land. The big snapping turtle can suddenly attack other animals, and the small snapping turtle can use its body to turn around to find the target, and even chase after it. Fingers and toes are webbed, aquatic, inhabiting deep rivers, lakes and bogs, and occasionally touching salt water areas. Crocodile turtles have good adaptability to shallow water and deep water under artificial breeding conditions, but they should be given shallow water environment because of their poor swimming ability in larval stage. Crocodile turtles are carnivorous, feeding on fish, shrimp, frogs, salamanders, small snakes, ducks, waterfowl, aquatic plants and fruit drop. Like night activities and food intake. The reproductive habits of big snapping turtles and small snapping turtles are not exactly the same. The mating period of American snapping turtle is 4- 1 1 month, and there is ovulation. In the middle and lower reaches of the Yangtze River in China, the spawning period is from May to August (the spawning time can be advanced and extended in high temperature areas), and generally, every spawning is 15-40. The actual situation changes according to the size and development degree of the mother turtle, which can be seen in the breeding season. /kloc-0 spawns many times a year. I have seen 9 kg parents lay 1 10 eggs a year, all of which are fertilized and hatched. The mating period of American crocodiles is February-April, and the spawning period is April-June, with each spawning10-52. Under natural conditions, the incubation period of the eggs of the big snapping turtle and the small snapping turtle is 9~ 18 weeks, and it will be longer when the weather is cold and dry. Artificial temperature control can shorten the incubation period of snapping turtle eggs, and snapping turtles can hatch after 60 days at 32℃.
2 farming techniques
2. 1 turtle pond construction
The new turtle farm should be built in a place with good water source, quiet environment and convenient transportation. The main body of turtle farm includes turtle farm itself, dining table, land, water intake and drainage system, overflow port and so on. The land is mainly used for turtles to rest, and the land of parent turtle farms is partly used for building spawning grounds.
The turtle pond is a brick cement structure, and the pond is polished with cement slurry to prevent the turtle skin from being scratched. Generally, it is a rectangle with a length from east to west and a width from north to south, and it can also be built into a circle. The size should be adapted to local conditions, with a depth of 50~80cm and the deepest part not exceeding 120cm. 8~ 10cm anti-escape pool, also known as calendering. The rectangular tank bottom is arranged in a high and low inclined plane, and the circular tank bottom is arranged in a pot bottom shape, which is convenient for sewage discharge.
Dining table13 enters the water, 2/3 comes out of the water, and it is inclined at 30 degrees with the water. In fact, the underwater part is also called the approach slope, and the water part is the dining table. If it is a turtle pond, the water part of the dining table can also guide the turtle to climb to the spawning ground. It is reasonable to set the dining table in the north of Guitang facing south. The width of the dining table is about 2m, and the length is 80% of the length of the pool. The spawning ground is 2~3m wide and the same length as the feeding table, and it is filled with 20~30cm fine sand. Building a shelter above the spawning ground is beneficial for turtles to lay eggs in rainy days.
The diameter of the inlet and outlet pipes should be at least 10cm, which can speed up the inlet and outlet of water and help clean up sewage. It should be noted that the water outlet should be located below or near the food table, because there is the most dirt near the food table, and turtles like to excrete near the food table after eating. The overflow port is located at the highest water level above the wall of the turtle pond, which is convenient for discharging organic suspended solids and flood discharge in rainstorm season.
After the turtle pond is completed, it should be soaked in clean water for at least 1 week to remove alkalinity. Then use 150ppm quicklime for disinfection, and only fresh water can be released.
2.2 Crocodile turtle breeding
2.2. 1 female turtle selection
Parent turtles generally choose wild original species, requiring good health, no trauma and internal injuries, over 5 years old, with specifications of over 2.5kg, preferably 4~5kg. If artificially propagated snapping turtles are used for seed production, healthy turtles over 4 years old and over 6 kilograms must be selected as breeding turtles. Whether a sexually mature female turtle is pregnant with eggs can be checked by eyes, hands and light, and the male turtle is lively and active. Both female and male turtles should be agile and touch their heads. Crocodile turtles should immediately open their mouths and whine to show their ferocity. The mother turtle's contraction of her legs and feet by hand strongly indicates that she is in good health. Carefully observe whether the turtle's head and neck are flexible, check whether the neck is swollen, open your mouth to see if there is a fish hook in the throat, and check whether there is a fish hook in the turtle with a metal detector. The ratio of male to female depends on the size of the turtle. Take wild soft-shelled turtle as an example. In general, the ratio of 2: 1 is suitable for small parents of about 2.5kg, the ratio of 3: 1 is suitable for medium parents of about 4kg, and the ratio of 4: 1 is suitable for large parents above 5kg.
2.2.2 Parent turtle breeding
In order to promote the gonad development of parent turtles, keep the environment quiet and the water quality excellent, discharge sewage and replenish fresh water in time, disinfect turtle ponds, parent turtles and water bodies, and use microecological agents to make beneficial bacteria dominant. Disinfectants and microecological agents cannot be used at the same time. Commonly used drugs include residual quicklime, chlorine dioxide, PVP-I, hydrofluoric acid, Nosaxin, etc. Commonly used microecological agents are photosynthetic bacteria and Nosacin. Use fresh animal bait, such as miscellaneous fish, shrimp, snails, earthworms, etc. Put an end to feeding spoiled bait. Animal bait can be disinfected by soaking in salt. If it is a wild parent turtle, the feeding time is mainly at night, accounting for 70% of the daily feeding, and the remaining 30% is released in the morning and gradually domesticated for daytime feeding. You can if you don't domesticate, but the workload will increase at night. Parent turtles raised artificially are fed/kloc-0 times in the morning and afternoon, 40% in the morning and 60% in the afternoon. Parent turtles have high nutritional requirements for feed, and vitamins and minerals can be added to the feed. The method is to inject nutrient solution into the bait fish, and green additives beneficial to the gonad development of the parent turtle can be used, such as traditional Chinese medicine, mold preparation, bioactive chromium, microecological preparation and so on.
2.2.3 Hatching of turtle eggs
Collection of tortoise eggs. After 9: 00 am the next day after spawning at night, it is usually collected in the afternoon. Newly collected snapping turtle eggs should be marked in the incubator and recorded separately. The collection box can be directly used as an incubator. The box is paved with sand in advance, with a thickness of about 10cm, and the eggs of snapping turtles should be handled with care. At the end with white fertilization spots, the animal pole is placed upward, and the boundary between the animal pole and the plant pole is obviously a normal fertilized egg. If the boundary is unclear and fertilization points are scattered, it means that the egg is not fertilized enough and no unfertilized eggs can be seen. Experience shows that unfertilized eggs are attached to the sand on the surface of snapping turtle eggs, while fertilized eggs are attached to smooth surfaces. Why should snapping turtle eggs be handled lightly? Because snapping turtle eggs don't have protein mesentery, careless operation will affect hatching.
Incubator. Food containers, wooden boxes and foam boxes can be used instead. The height of the container is over 65,438+00 cm, the crocodile eggs cover 65,438+0 layers, and the eggs are placed in the middle of the sand. The sand under the egg is 3cm thick, the sand around the egg is 3cm thick, and the egg is covered with 4cm. The spacing between eggs is about 1cm. For ventilation, bottom sand 1/2. It is also feasible to use sponge instead of sand as culture medium.
Culture temperature control equipment. Automatic heating and temperature control device (ZL * * * * * * * * X) National patent, reliable and practical. The power and temperature of the equipment can be adjusted, and it runs automatically without special care.
Incubation room is built with a corner of the house, or it can be specially built. The key is to use thermal insulation materials, to place thermal insulation materials on the walls around the incubation room, to set up incubation racks indoors, and to put the incubation boxes on the racks with a certain distance between them, which is convenient for watering and moisturizing. Another method is to put the incubator directly on the ground, then put bricks on the four corners of the incubator, and then put the second incubator on the bricks, so as to stack it layer by layer. Another method is to directly lay 1 layer of sand on the floor of the incubator, and correspondingly lay 1 layer of eggs in the sand, and set 1 sink on one side of the sand bed, so that young turtles can automatically climb into the sink after hatching. In addition, a special incubator is used to simulate the hatching of scarabs. Small incubators are placed layer by layer in the incubator, and temperature control equipment and small fans are used in the incubator.
Temperature, humidity and ventilation are the three elements of snapping turtle hatching, and they are also the eternal theme of all turtles hatching. The hatching rate of snapping turtles needs to be controlled at a constant temperature of 32℃. The young turtles will hatch in about 60 days, and the sand temperature is inconsistent with the air temperature. Generally, the sand temperature is controlled at 32℃ and the air temperature is about 35℃. Humidity control includes absolute humidity and relative humidity. Absolute humidity means that the water content in sand is about 8%, which is released by hand rubbing. The relative humidity of the air in the incubation room can be measured by a hygrometer. The main way to maintain the relative humidity of 85% required by snapping turtles is to spray water from time to time manually. Spray water as much as possible in the early stage of incubation, and spray water as little as possible in the later stage, and keep it dry to prevent the formed young turtles in fertilized eggs from being affected by too much water. Moreover, excessive watering is not conducive to the breathing and ventilation of fertilized eggs.
The larvae belong to the temporary rearing period within 1~2 weeks after hatching, and the yolk sac of the newly hatched larvae is gradually absorbed in about 2 days and enters the artificial temporary rearing process. The open feed for young turtles can be egg yolk, pig liver, red worms and special compound feed. Plastic pots can be used as temporary breeding containers, and the density is about 0/00 per square meter/kloc. Be careful that the water is not too deep, preferably 2~3cm, which is limited to the turtle's back. Too deep a water level can easily lead to drowning, because young turtles have just hatched and their swimming ability is poor. Because the water level is shallow, the water quality is easy to deteriorate, so it is necessary to change the water frequently. The container is small, and the water is changed 1~2 times a day. If it is raised temporarily in a large special pool, it is generally changed every 48 hours 1 time.
2.3 Industrialized turtle breeding
After the end of the temporary rearing period, the young turtles enter the stage of industrial reproduction. At present, it is mainly through the technical means of automatic temperature control in the factory to put young turtles in the best environment, accelerate the growth rate and shorten the breeding cycle. After the young turtles hatch in batches, they gradually enter winter. Under natural conditions, young turtles are too poor to survive the winter, resulting in many deaths. Under artificial conditions, given the best temperature and complete feed, and taking necessary ecological control measures, young turtles can be raised in the greenhouse in winter and spring, and the specifications can reach about 500 g. When the temperature rises in summer, they will be moved out of the greenhouse and raised in an open-air pond in the natural environment, and in a few months they will grow into commercial turtles of1500 g. Practice has proved that the growth of young turtles is slow, and the growth rate of snapping turtles is accelerated when they reach more than 250 grams. When the size reaches 500 grams, it grows faster when it is moved to the outdoor feeding stage, with an average weight gain of 200 grams per month, which is amazing. In other words, it only takes 1 year for the snapping turtle to grow from about 7g to1.500g.. If cultured at natural temperature, not only the survival rate is low, but also it takes three years to reach the specification of 1.500g commercial turtle. Therefore, industrialized breeding of snapping turtles can shorten the breeding cycle by 2 years. The market is ever-changing, and early output is beneficial to seize opportunities, reduce unit costs and improve competitiveness.
Basic points of industrial breeding of snapping turtle: 1) shed construction. Adopting energy-saving greenhouse not only saves investment, but also saves heat energy after improving thermal insulation performance. The method of using two layers of film to sandwich insulation materials on the roof and four walls to sandwich insulation materials, paying special attention to the indoor ground must be paved with insulation materials, so as to ensure the insulation and energy-saving effect of the greenhouse. In fact, the principle of building a turtle greenhouse is the same as that of building a cold storage, and the insulation effect should be ensured. 2) Temperature control device. Advanced patented technology can be used in both small and large greenhouses. The automatic hot water circulation energy-saving heating device in soft-shelled turtle greenhouse has obtained the patent certificate issued by China National Intellectual Property Administration with the patent number of ZL * * * * * * * * .4. The biggest feature of this patent is that anthracite is used to automatically heat the air in the greenhouse and the water in the regulating pool. The key is the automatic circulation of hot water to ensure the need of isothermal water change. The daily coal consumption is only 500 grams per square meter, and the energy saving effect is remarkable. 3) Oxygen-increasing equipment. Greenhouse is characterized by high temperature, high density and high pollution. Aerobic treatment is helpful to improve water quality, help organic matter decompose and reduce pollution. Generally, every 500 square meters of greenhouse is equipped with a 2.2 kW aerator. 4) The water inlet and outlet system and the bottom of the pond should have a certain inclination, which is the same as the outdoor turtle pond construction requirements. It is simple and feasible to insert a PVC pipe with a diameter of 10cm into the drainage pipe to stop water and draw out the drainage. 5) The setting of the dining table. Put asbestos shingles into turtle pond obliquely, underwater 1/3, and water surface 2/3. Feeding begins under the table and gradually moves to the water for feeding, which is beneficial to observe the feeding situation and reduce the residual bait. 6) Disinfection and disease prevention. After being diluted with quicklime slurry regularly, it spills all over the pond, and the turtle water is automatically disinfected regularly with advanced ozone generator, which has good effect and low cost. 7) Feed distribution. It is best to make your own feed, buy a small feed production unit and use advanced feed formula. The basic components of crocodile turtle feed are white fish meal, α-starch, plant protein, minerals, vitamins, probiotics and prebiotics. Other green feed additives can be added to promote the growth of crocodile turtles, reduce the occurrence of nutritional diseases and improve the survival rate of culture. 8) Feeding management. Young snapping turtles are fed with compound feed during the growing period. If it is powdery feed, add water, corn oil and fish oil to make soft particles or balls and put them on the dining table. If the cultured species is the snapping turtle, the puffed feed floating on the water surface is fed to form power bait to lure the inactive snapping turtle to swallow. Feed it twice a day, and the amount of each feed should basically be eaten within 2 hours, leaving only a little. When the water quality changes and the ammonia concentration is high, change the water in time. Conditional turtle farms can use classical hydrochemical analysis methods or modern instruments to automatically detect water quality, and can use computer monitoring to track the activities of snapping turtles in greenhouses and take immediate measures when problems are found. Modern technology has realized automatic test, automatic water change, automatic analysis and automatic alarm. During the feeding process, special attention should be paid to "isothermal water exchange". When the young turtles are moved from outdoor to indoor, the temperature should be gradually raised, and when the young turtles are moved outdoors, the temperature should be gradually lowered, and the temperature balance should be paid attention to. Always remember the words of 12 in the whole process of breeding: "environmental regulation, structural regulation and biological regulation", and savor it carefully.