1. Lighting: Illuminate the crab's abdomen with a flashlight. If you see that there is no hollow body, it is a crab with full crab yellow. 2, the navel is round: the crab yellow is the female crab, first pick the crab yellow. The female crab is unique in that the navel is oval or round, and the male crab is in the shape of the Yangtze River Delta. Look at the position of the navel, it is more prominent, and you can see a yellow substance, that is, crab yellow feet.

1, lighting:

Shine a flashlight on the crab's abdomen. If you see a solid body without a hollow body, it is a crab with a full crab yellow.

2, navel convex:

Crab yellow is a female crab, so you should pick the female crab first. The female crab is unique in that the navel is oval or round, and the male crab is in the shape of the Yangtze River Delta. Look at the position of the navel, which is more prominent. There is a yellow substance, which is the crab yellow foot.

Extended data:

Crab is a crustacean, belonging to the mollusk class Decapoda. Its body is protected by a hard shell and it breathes through its gills. Taxonomically, it is the same kind of animal as shrimp, lobster and hermit crab. Most kinds of crabs live in the ocean or offshore areas, and some live in fresh water or land. Common crabs are Portunus trituberculatus, Portunus trituberculatus, Eriocheir sinensis and Eriocheir sinensis (Eriocheir sinensis, Eriocheir sinensis and Eriocheir sinensis).