Crabs are generally covered with a thick exoskeleton, composed primarily of calcium carbonate, and armed with a single pair of chelae. Crabs are found in all of the world's oceans, while many crabs live in fresh water and on land, particularly in tropical regions.
As a Food:
Crabs are eaten in many countries around the world. They are used in many different dishes, including bisque, curry and crab cakes, as well as cooked whole, steamed, boiled, baked or fried. Some species, such as soft shelled crabs, are eaten whole (generally after molting). Crab is considered a delicacy in many countries and is often substituted with cheaper imitation crab meat, which may contain a small amount of real crab meat, but is mostly made from artificially flavored fish.
Health Benefits of Crab:
Crabs are good sources of chromium, which works with insulin in the metabolism of sugar helping the body to maintain normal blood glucose levels. Studies indicate chromium helps to raise the levels of HDL (or "good" cholesterol), which can reduce the risk of coronary artery disease and strokes. It is especially beneficial for diabetics.
Crab and shellfish also contain goodly amounts of selenium, a trace element of critical importance that works as an antioxidant, detoxifying potentially carcinogenic substances such as mercury, cadmium, and arsenic which could lead to tumors.
Crabs, like all shellfish, are also rich in omega-3 fatty acids, which it gets from phytoplanktons and algae. Omega-3 fatty acids, help in reducing the stickiness of blood platelets, thus making red blood cells more flexible and ensuring smoother flow. Omega-3 helps to reduce the level of tri-glycerides and LDL (low-density lipo-proteins), which choke up artery walls as deposits.