The biggest feature of the crab is a pair of claws of great size, and the large claws placed on the front chest resemble the shield of a samurai. The tide crab will make the action of dancing large claws, so it is called the tide crab. The purpose of this "tide-stirring" action is to intimidate the enemy with a large claw, or to court.
Morphological characteristics
While foraging, both eyes stand tall and observe movements around. Evacuate quickly as soon as the situation is discovered. The biggest feature of male crabs is a pair of claws of very different sizes, the large one called mating claws, bright colors, and special patterns. It weighs almost half the body and is more than three times the diameter of the crab's carapace; the small claws are extremely small and are used for feeding, called feeding claws, which scrape small particles rich in algae and other organic matter on the surface of the silt and send them into the mouth. If the male unfortunately loses a large claw, a small claw will grow in the original place, and the original small claw will grow into a large claw instead, performing the same function. The female crab is about the same size and shape as the male crab, but both claws are quite small and symmetrical, knuckle-shaped, and both are feeding claws. Males are brighter in color than females , and include coral red , bright green , golden yellow , and light blue.
Busy tide crabs on the beach
Characteristics of life
Tide-catching crabs inhabit salt and brackish water beaches, survive in muddy areas, live in cave dwellings, and often have dedicated burrows, but are often replaced every few days. The depth of the burrow is related to the groundwater table, the depth of the hole can reach 30 cm, and the bottom of the cave generally needs to reach the wet soil. Many male crabs also build a semicircular umbrella-shaped cover that covers the opening of the hole. The activity of the tidal crab has a certain pattern with the rise and fall of the tide, stopping at the bottom of the cave at the high tide, moving to the beach after the low tide, feeding, repairing the cave, and finally occupying the cave and preparing to mate.
Tidal crabs and mudskippers compete for territory
Big Ao takes the lead
The male crab has the iconic action of dancing the large claw at high tide, which has a variety of meanings: such as a warning effect, if a male crab approaches another family's territory, the "landlord" will shake the large claw as a warning signal; or he will also use the large claw to slap on his carapace or silt ground, warning through sound. For example, the big fish is sometimes also a courtship tool, and some kinds of tidal crabs use this slapping sound to attract female crabs into the hole. If two male crabs compete for territory or the opposite sex, the large claw becomes a powerful fighting weapon.