"Nine females and ten males" refers to September female crab and October male crab. Also known as "the navel in September and the tip in October".

The umbilical cord is a female crab, and the umbilical cord is a male crab. It means to eat female crabs in September and male crabs in October. Therefore, in September of the lunar calendar, the digestive glands and ovaries of the female crabs grow into crab roe to prepare for the winter and the need for reproduction in the coming year (crab roe becomes crab roe in spring).

Life habits:

Looking for food

Crabs spend most of their time looking for food. They are generally not picky eaters. They can eat all the food they can get with their claws. Small fish and shrimp are their favorite, but some crabs eat seaweed, even animal carcasses and plants.

compete

Crabs eat other animals, and other animals may also eat crabs. For example, humans regard crabs as delicacies, and waterfowl also eat crabs. Some fish also like to eat crab feet like humans. Young and underage crabs may be preyed by other marine life when they float in the sea in groups, so crabs have to lay a lot of eggs when laying eggs to ensure the survival rate of crabs.

breed

They rely on the mother crab to give birth to small crabs, and every time the mother crab will lay a lot of eggs, the number can reach more than millions. After these eggs hatch in the abdomen of the mother crab, the larvae can leave the mother and float around with the coastal current.

After several times of molting, it grows into a big-eyed larva, and the big-eyed larva grows into a young crab after several times of molting. The appearance of the young crab is almost the same as that of an adult crab, and it becomes a crab after several times of molting. Most marine crabs are discharged directly into the sea without hatching after their eggs mature.

Body shape introduction:

Although the crab is small, it is all-sided. After removing the hard shell of the crab, we can find that the body part of the crab is protected by a shell. These shield-like shells are called carapace by biologists.

Crab body is symmetrical, which can be divided into forehead area, eye area, heart area, liver area, stomach area, intestine area and gill area. Both sides of the crab's body are connected by appendage. The appendages of the head are called tentacles, which have the functions of touch and smell. Some appendages have the function of mouth, which is used to tear food and send it into the mouth.

Crab chest has five pairs of appendages, which are called pectoral feet. A pair of appendages at the front are equipped with strong claws, which can be used for foraging. The other four pairs of appendages are the feet of crabs. The crabs rely on these four pairs of appendages to walk and move. They walk in a unique and interesting way, and most of them walk sideways instead of straight ahead. Except for monks and crabs, they walk straight.