When it comes to crabs, perhaps most people have the impression of "hard armor from head to toe, walking sideways, opening teeth and dancing claws with eight feet, and often spitting foam in the mouth", and the afterword we learned before is also "crab walking - rampant and domineering". In fact, not all crabs walk horizontally, there is such a crab that walks straight, it is a short-fingered monk crab.
Short-fingered monk crab (Mictyris brevidactylus), belongs to the genus of monk crabs in the decapod family of monk crabs, also known as monk crabs, soldier crabs, sea pearls, sea monks, pearl crabs, mashed rice crabs, sea spiders, blue angels, wave crabs and so on. They have a spherical carapace, rounded, pleasant sky blue, with a striking white claw and a foot, the foot and the cephalothorax are red, quite gorgeous, like a sapphire ring, making them stand out in their class. The average weight is only about 2 grams, the two claws are so large, there is no obvious difference between male and female, you need to open the abdomen to distinguish, if there is a specialization of the abdominal limbs into a rod-shaped handover is a male crab.
Because the carapace is round, the short-fingered monk crab walks in a very different way from other crabs, not to run amok, but to go straight forward. They prefer to inhabit the tunnels of intertidal sand, filter the organic matter and algae in the sandy mud for food, and then make the remaining sand mud into round mud particles to spit out, leaving small mud beads on the mud beach called feces.
Juvenile crabs and female crabs have weak mobility, often hiding in the hole, slightly exposed double claws to feed on the surface of the soil, filtered after the feces piled up on the surface, this feeding method such as gopher digging tunnels, so called "tunnel feeding". Adult male crabs usually go out in groups to feed at low tide, often reaching hundreds of them, like an army marching, full of momentum, which can be said to be an imposing and cute blue regiment on the mudflat. Once in danger, the body will be erected on its side, while digging the sand with its feet, it will rotate the body in a spiral manner, and gradually bury it in the sand, like a screw, into the emergency hiding place. However, each mud cave can only accommodate one short-fingered monk crab, and if it is invaded by the same kind, the two sides will fight.
Source: Aquatic Animal Health Assessment
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