Animal theory of local cattle
In the woodland or fertile soil of Paipu in Danzhou, Hainan, there is an underground animal called "ground cow", commonly known as "concave butterfly". The largest animal is only as big as a corn kernel. It consists of an oval belly and a small head. After the belly was crushed, it was a pool of blood. There is a crab-like clip in front of the head, which is used for attack or defense. When escaping, most of them drill sand into the ground to hide. Its "home" is concave to the ground like a funnel, all paved with fine sand. It is hidden on one side of the leak in the funnel. If it doesn't move, dig holes and accumulate fine sand, it will be difficult for people to find out where it is, only knowing that it is on one side of the tip of the funnel-shaped "home". It is said to have the efficacy of traditional Chinese medicine, mainly used for promoting blood circulation. It is one of the drug directions for preparing traditional Chinese medicine for treating gallstones, and can drive other drug-induced components to act on gallstones. The price of concave butterfly is very expensive. Newly dug live concave butterflies with a little sand and mud can be sold for RMB per catty in 400 yuan. After processing, steam it with warm fire (carbon fire is also necessary) until it can be ground, and it can be sold at RMB 1000 per catty.