2. If the turtle's hind nail is sunken, its mental state is good, its eating activities are all normal, and its limbs crawl smoothly, it is likely to be the brand of malnutrition of its larvae, so it is no problem to buy such a turtle.
3. The limbs crawl smoothly without shaking. A relatively healthy turtle can recover quickly and forcefully by gently dragging its limbs. When crawling, its tail often swings from side to side, which is also a very important feature to observe the turtle's health.
Extended data:
Turtles are divided into head, neck, trunk, tail and limbs: the special morphological structure that is significantly different from other reptiles is that it has a turtle shell, and its wide and short body is contained in the turtle shell. Tortoise shell is composed of arched carapace and flat carapace: the carapace extends at the side of the body and is connected with the carapace through seams or ligaments. This extended part is called the nail bridge. The head, limbs and tail extend from the edge of the turtle shell and can generally be retracted into the shell (except for flat-breasted turtles). The carapace and carapace are composed of two layers: the inner layer is composed of several bone plates and the outer layer is composed of several horny shields.