Limulus is a marine arthropod, xiphophora, which is a national second-class protected animal. Shaped like a crab, it is green-brown or dark-brown, covered with a hard shell and has four eyes, two of which are compound eyes. There are two small eyes of 0.5mm in the front of the head and breastplate, which are the most sensitive to ultraviolet rays and are only used to perceive brightness.

Although horseshoe crab can push its body to swim by flapping its gills downward, it usually bends its body into an arch, dives into the mud, and then pushes its body forward with its tail sword and its last foot.

Living habits

It has a wide range of feeding habits, mainly animals, and often feeds on benthic and woody small crustaceans, small mollusks, annelids, starworms and sea bean sprouts. Sometimes I eat some organic crumbs. Limulus amebocyte lysate has always been human food and natural enemy of soft-shelled crabs. If it is juvenile horseshoe crab, the food is mainly unicellular algae, rotifers, larvae of harvest insects and copepods. If you are an adult, you can eat shrimp and small fish. The most distinctive thing is that the blood of horseshoe crabs is blue.

It is a warm benthic arthropod, inhabiting the shallow sea area with a water depth of 20-60 meters, and likes to dive in sand caves, only exposing the tail of the sword. The horseshoe crabs are the most abundant in the harbor waters, which are in the middle depth water in winter and on the mudflats in the intertidal zone in summer.