King crabs are any of the species of crabs that belong to the taxonomic Family Lithodidae, which has 14 genera and 40 species total. The best known king crab is the Alaskan King Crab. All crabs are crustaceans, so they have a hard exoskeleton that protects them, 5 sets of legs (only only 4 may be visible), and antennae. Usually when people think of king crab, they think of a nice and tasty dinner. What they don't think about is what they do for our community. Crabs help keep the population of certain creatures down as well as providing others with food. 
Crabs have bilateral symmetry, which means that both halves are identical on the outside (not technically on the inside). Crabs have 5 sets of legs: 1 pair of chelipeds and 4 pairs of legs. The chelipeds are used for catching food, defense, mating, and many other uses. Crabs have a large shield called an exoskeleton, which covers their entire body for protection. Every so often the crabs must shed their exoskeleton because it gets too big, then they just grow a new one. The mouthparts of the crabs are called mandibles. King Crabs are omnivorous, meaning they eat plants and animals, even each other!
King Crab reproduction is much more aggressive and unusual than normal animal reproduction. They have internal fertilization. Males seek out females who have not yet molted. The male then grabs hold of the female and begins mating with her when she molts. The male gives the female a sperm packet called spermatophores and the female keeps them in holding areas called spermathecae. After this the male will not leave the female until she grows back her shell. Certain types of female crabs will store their packets for long periods of time before using them. Also, crabs do not have to mate in order to reproduce. Female crabs carry their own sperm packets that they can use to fertilize eggs if no mate is found. 
King Crab are a normal part of our ecosystem. They help keep the population of sea stars and other invertebrates at a reasonable level.  As adults, a King Crab's diet includes echinoderms and barnacles, worms, mollusks, and sponges. They usually live at 190 ft below the surface and usually prefers mud bottoms.  At about 2-4 years old, the crabs stop living alone and seek out large groups of crabs called pods. These pods are formed in the attempt to get predators to leave them alone. After a year or two they will then go out and seek mates. Predators to King Crab are: certain fish (such as halibut), octopi, sea otters, certain worms, humans (of course), and even other King Crab, proving that they are cannibals. 
- Main Article: Molting
King Crabs have shells that do not grow, so they must shed their shells periodically to get bigger. This process is called Molting. Crabs molt around 27 throughout their lives. King Crabs shells do not grow as the crabs do (like our skin does with us) because their shells are too hard. So the crabs pull themselves out from their old shells (even the eyes have transparent shells) and take in water. During this time the crab is much more meaty look because there is nothing protecting it. It then takes out three days to regrow the new shell, if the crab survives long enough. This is a regular process.
Spider Crab on top of a Tasmanian King Crab
- northwest-seafood.com Information on King Crab
- anatomy and taxonomy of the King Crab by Marine-Life
- Reproduction by NOAA
- Life style by NOAA
- Life style Answers
- serc.si.edu Molting