Horseshoe Crab.pdf

The horseshoe crab is a marine animal with a history dating back 600 million years, with 26 phyla of marine organisms found in the ocean. It has 10 eyes, including two pairs of true eyes, and can polarize light, concentrate it, and detect infrared and ultraviolet lights. The crab's unique physiology and optic nerves have inspired developments in navigation, solar energy collectors, and video systems.

The horseshoe crab has a patchy distribution pattern, with highly specialized methods for detecting habitats for reproduction and dispersal. There are four species with confirmed morphology, and three genera worldwide, with Malaysia having an abundance of three species. The crab's blood, or haemolymph, turns blue when exposed to air and is used to diagnose endotoxins.

The horseshoe crab has various uses, including its tail spines being used as spear tips, its carapace being used as a hat or ladle, and its eggs being regarded as a delicacy. The meat of its appendages is also eaten in some parts of China. Pregnant women in Singapore eat the egg mass for immunity for their foetus. The crab's unique characteristics have contributed to its long survival, with an ability to tolerate wide ranges of salinity, temperature, desiccation, and submergence.