Physical characteristics of crabs:

Although the crab is small, it covers everything. 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 crustaceans by biologists.

Crabs are symmetrical and can be divided into forehead area, eye area, heart area, liver area, stomach area, intestine area and gill area. The two sides of a crab are connected by appendages. 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 chest feet. A pair of appendages at the front end are equipped with powerful claws, which can be used for foraging. The other four pairs of appendages are crab feet. Crabs rely on these four pairs of appendages to walk and move. The way they walk is unique and interesting, and most of them walk sideways rather than straight.

Except monks and crabs, they all walk straight. Based on the characteristics that the two feet at the tail end of crab are less involved in walking? Imitating the walking mode of crabs, a 6-legged lateral moving walking mechanism was developed, and its motion characteristics were studied to meet the requirements of walking on rigid ground and soft ground in agricultural production.

Extended data:

The living habits of crabs

1, looking for food

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

2. Competition

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

3. Reproduction

They rely on the mother crab to give birth to small crabs, and every time the mother crab will lay a large number of eggs, the number can reach more than one million. 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 molting several times, it grows into a big-eyed larva, and after molting several times, it grows into a young crab. The appearance of a young crab is almost the same as that of an adult crab, and it becomes a crab after molting several times. Most sea crabs are directly discharged into the sea without hatching after their eggs mature.

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