The way to see if a crab is alive is as follows:

One, smell:

The most direct way to determine if a crab is alive or dead is to smell it. Whether it is a sea crab or a river crab, there is usually a fishy smell, which is inevitable, but a dead crab will smell a little bit stinky because it has begun to decompose and rot, and this smell can not be covered up, so it is easy to smell out.

Second, look at the eyes:

The dying crab may not have much vigor, or it can't move because its body is tied up, but its eyes can move. Observe its eye stalks, or touch some of them directly, live crabs can move on their own, while the eyes of dead crabs will not move, this method of judgment is also more accurate.

Three, pour some water:

The crab is breathing with gills, which may not be obvious in the air, but as long as there is water, it is easy to see. Pouring a little water on its mouth will automatically open it if it is still alive, while it will not react if it is a dead crab. Also, living crabs will spit bubbles when they breathe.

Fourth, untie the rope:

Generally bought crabs are tied up with rope, which restricts its activities, plus the low temperature preservation causes it to be dormant, so it is not easy to say whether it is dead or not. You can put it in a room temperature environment, and untie the rope, wait a while to see if it will crawl, alive generally will move a little.