The common soft-shelled turtles in China mainly include Chinese soft-shelled turtle, soft-shelled turtle, spotted soft-shelled turtle and giant salamander. The Chinese soft-shelled turtle is about 30cm long, flat and generally oval, with basically the same appearance color, and no bright spots and light spots. The head is thick, the front end is triangular, the snout is tubular, and the snout is equal to the eye diameter. The nails on the back are dark green or yellowish brown, and the nails on the abdomen are grayish white or yellowish white, which is relatively smooth. The limbs are flat, each with five toes and webbed toes.

1. How many varieties of soft-shelled turtle are there?

The common species in China are soft-shelled turtle, soft-shelled turtle, soft-shelled turtle and giant salamander. Introduction is as follows:

1, Trionyx sinensis

(1) is about 30cm long, flat and oval, with nails on the back and abdomen. The whole body is covered with leathery skin, soft and without horny shield. The appearance color is basically the same, and there is no bright spot. The head is thick, the front end is triangular, the snout is tubular and relatively long, and the snout is longer, which is equal to the eye diameter. The eyes are located on the back sides of the nostrils, there are no teeth in the mouth, and the neck is cylindrical, slender and free to stretch. The nails on the back are dark green or yellowish brown, and the nails on the abdomen are grayish white or yellowish white, which is relatively smooth. The tail is short, the limbs are flat, each with five toes (the inner three toes have sharp claws) and webbed between the toes. The hind limbs are more developed than the forelimbs.

(2) Usually inhabit rivers, lakes and swamps, ponds, reservoirs and other fresh water areas where the water flow is gentle and fish and shrimp are flourishing.

2. Eriocheir sinensis

(1) The back plate is about118.5-315 mm long and 97.5-255mm wide, and is generally oval.

(2) The head is relatively large and the back of the head is smooth; The front of the head is thin, the snout is prominent, there is a snout (about 8.5-9 mm long), and the nostrils are located at the top of the snout; The eyes are very small, and the distance between the two orbits is less than the diameter of the orbit (9.5mm). The upper jaw protrudes from the lower jaw and has fleshy lips, in which the lips on both sides of the upper jaw are separated and split in the middle, and the beak can be seen.

(3) There is leathery skin on the surface of the dorsal disc, and the front edge is turned backward to form a developed marginal ridge with a row of large and prominent Mylabris; There is a longitudinal ridge in the center of the dorsal disc, extending from the front end to the rear edge of the bony backboard, and irregular nodules are distributed on both sides (the nodules at the rear edge of the dorsal disc are large and dense).

(4) The ventral surface is smooth, the upper web is long, the front of the inner web is tangent (at an acute angle), and both sides of the inner web point backward and outward; The lower corner of the sword net is round.

(5) The limbs are flat and round, with webbed toes and three claws.

(6) Usually inhabit in the sand and mud of streams, ditches, rivers, shallows and ponds.

3. turtle

(1) The back plate is about 36-57cm long, the back plate is rectangular, and the width of the back plate is only slightly smaller than the length, generally circular.

(2) The body is flat and slightly raised. The back is smooth and shiny, dark olive, dotted with many yellow spots, and there are a lot of small yellow spots between the larger yellow spots, sometimes surrounded by small yellow spots, forming irregular circles, while others form narrow lines; In the part corresponding to the bone nail, yellow stripes form criss-crossing lines or radial lines. The head, neck and back of limbs are all black with irregular yellow stripes, which is one of the main characteristics of turtles.

(3) The abdomen is grayish white, and there are only two undeveloped calluses at the joint between the tongue plate and the lower plate.

(4) The skull is flat, wide and short, of medium size, with short and round bone kiss, and the mandibular joint is narrower than the maximum orbital diameter without central ridge; The basal sphenoid bone is connected with the jawbone, and the yoke bone is in contact with the squamous bone. Between the first pair of ribs, only 1 laminate is separated, and the eighth pair of ribs degenerates and does not meet at the midline. 7-8 texture layers form a continuous 1 row; The tongue web is separated from the lower web and does not merge; The front webbed is small, separated from each other, and webbed between toes.

(5) They usually live in the freshwater areas of the Yangtze River Basin and the Red River Basin.

4. catfish

(1) is the largest turtle, with a body length of about 600m, a small head, a short and round nose and mouth, less than half of the eye diameter, nostrils in the nose and mouth, a wide and smooth head and back, and a tail beyond the skirt.

(2) The back is flat, wide and round, with Oracle Bone Inscriptions on the back, flat front edge, slightly concave rear edge and dense distribution of concave markings; There are 8 vertebral plates * * *, the front four are hexagonal, the fifth vertebral plate is oval or nearly rectangular, the back three short sides face forward, and only the eighth vertebral plate is small pentagon; There are 8 pairs of ribs, and the eighth rib has no obvious degradation. Except for 1 and 8 ribs, the outer edge of ribs is larger than the inner edge, especially the second and seventh ribs. The upper web is small and the left and right sides are not tangent; The tips of the inner webs are at acute angles or intersect.

(3) The back of the body surface is olive with yellow spots on it, and the abdomen is white.

(4) They mainly live in inland and slow-moving freshwater rivers and streams.

How many years does it take for two or three catties of soft-shelled turtle to grow?

1, the growth rate of soft-shelled turtle depends on the variety, sex and food richness of soft-shelled turtle.

2. If it is in the wild and there is enough food, it will take at least 5 years to grow to about 3 kg. If it is farmed artificially, it will take about 3 years to grow to about 3 kg.

3. The growth rate of Japanese species is about 20% faster than that of China soft-shelled turtle, and pearl soft-shelled turtle is faster.

4. When the weight 100-300g, the growth rate of female turtles is faster than that of male turtles; 300-400 grams, the growth rate of the two is basically similar; 400-500g, the male turtle grows faster than the female turtle; 500-700g, the growth rate of male soft-shelled turtle is almost 1 times that of female soft-shelled turtle.