The tidal crab is a genus of the phylum arthropods, the family Carapaceae, the decapods, and the family Sand Crab, with about 100 species.
Tidal crabs are widely distributed in the intertidal zone around the world except Antarctica, with tropical and subtropical distribution being the most widespread.
Tidal crabs are small and nest on sandy and muddy areas in the intertidal zone, or in lagoons and coastal swamps.
The most characteristic feature of the tide crab is its double claw, which varies greatly in size. However, only male tide-catching crabs have such an appearance, and the female tide-catching crabs have small claws.
The male crab that is the larger is called the courtship claw, and the smaller one is called the feeding claw. As the name suggests, the main role of the large claw is courtship. During the breeding season, male tide crabs will wave large claws for courtship, which looks like it is attracting tides, so it has the name of the tide crab.
This large claw is crucial for male tide-inducing crabs. When competing for female tide crabs, they will use large claws to wrestle for a point, while female tide crabs will prefer male crabs that have a stronger and more powerful one.
If the large chelation is broken during the duel or other accidents, a small claw will grow back on the broken part the next time it molts (molt), and the remaining small chelation will gradually become larger during several moults, forming a new large chelation.
The small claws of the tide crab are used for feeding. They will use small claws to clamp the sediment up and put it in their mouths, and the algae, fungi and microorganisms in the sediment will be screened out by the filter feeding organs, and the remaining sediment will be spun into a ball of mud and spit out. Therefore, when the tide crab eats, it will leave a mud ball on the ground, which is quite spectacular.
The lifespan of the tidal crab is two to three years. Because they are small and distinctive, they are kept as pets by some people.