Dungeness+crab

Kingdom: Animalia Phylum: Arthropoda Class: Malacostraca Order: Decapoda Infraorder: Brachyura Superfamily: Cancroidea Family: Cancridae Genus: Cancer Species: C. magister

The Dungeness Crab, or master crab, is about 8 inches big, altough it can grow up to 10 inches. It is the most commercially important crab to the Pacific Northwest. These crabs must molt their shells every so often in order to grow, this is called ecdysis. The shell is normally fairly wide and long and very hard. All 5 pairs of legs are also covered in this same type of shell. The Dungeness Crab uses its claws as both a defense and to tear its large food apart. It uses its legs to pass the food to its mouth. The crab’s stomach, which is called a gastric mill, is lined with "teeth"-like structures. Its diet consists mostly of clams and other crustaceans, although, this crab is a very good scavenger. When the Dungeness Crab feels threatened it buries itself completely in the sand to hide.

Mating for these crabs is very strange. The males are attracted to the females through pheromones that are in the female’s urine. The males "hugs" the female so that she is underneath and there tummies are touching and their heads face each other. This "hug" can last for several days. The actual mating doesn't happen until the female has molted. She shows that she is ready to mate by urinating on or near the male’s antennae. After several months the female lays the eggs and they stay on the underside of her belly for 3-5 months until they hatch. The baby goes through 5 different larvae stages. After ten molts or about 2 years the crab reach adult hood.

Although these crabs are thought to be only in the Pacific Northwest, they have been turning up in the Atlantic, Ocean. This concerns scientist about their effect on local wildlife.

By: Jon