Crabs are one of those creatures that fire the imagination. They are alien and monstrous in some settings, yet fun and cute in others–who can resist a hermit crab? If we look at the stars, there is a whole constellation named in honor of these animals. Certain crabs can also make a very tasty meal! This page takes a look at some the most interesting types of crabs and how they live. It is not so much an exploration of the different families of crabs as an examination of what kinds of places crabs live with examples of individual species. There is also an overview of the species that are most important to human beings whether as food, as a pest or simply as objects of curiosity.
European Spider Crab
The European Spider Crab or Maja squinado is a weird-looking migratory crab species found in the Atlantic Ocean and Mediterranean Sea. They migrate during autumn with some crabs covering more than 160 km in eight months. This crab is the subject of commercial fishery, with over 5,000 tonnes caught annually. This edible crab is also known commonly as Spiny Spider Crab or Spinous Spider Crab.
Red Frog Crab
The Red Frog Crab is a unique-looking crab species. Its scientific name is Ranina ranina. It is also commonly known as Spanner Crab. It can grow up to 15 cm in length and weigh as much as 900 grams. It is sold at a price of 400-500 pesos per kilogram in the Philippines.
It has a purplish-brown carapace, pinchers predominately white with several rows of rough protrusions along top edge. The highly prized dungeness crab is a common inhabitant of sandy substrates throughout the Northwest. Dungensess crabs molt in summer. I have witness massive motling events involving thousands of male dungeness crabs in the Cape Flattery area. And yes, these crabs can pitch very hard.
Purple Shore Crab
Coloration can vary, but typically purple bodu and legs with yellow blotches. No hair on legs. It is often difficult to avid this species when turning over rocks on a rocky shoreline. This species is seldom seen by divers, but is a common encounter for beachcombers.
Puget Sound King Crab
The rugged looking Puget Sound king crab is the largest crab in Northwest waters. I commonly note this species in the San Juan Island, and less often in the Cape Flattery area. It has a large, pronounced bumps on carapace top. Adults are predominately orange or orange/red with a mix of white, yellow and purple markings. Juveniles are often a red and/or orange.
Blue Swimmer Crab
It buries itself in mud or sand as it waits for the high tide, then emerges and swims strongly in search of food. A pair of flattened legs at the back of the crab make great paddles. It will eat shellfish, algae and small fish.
The Blue King Crab
The Blue King Crab or Paralithodes platypus is another large crab species. It can be found near St. Matthew Island, the Diomede Islands and the Pribilof Islands in Alaska and along the coast of Russia and Japan. Blue King Crabs from the Pribilof Islands are the largest of all the king crabs. They can attain weight of up to 8.2 kg and are commercially harvested.
The Columbus Crab (Planes minutus) clings onto weeds or other floating material like goose barnacles and, sometimes, even loggerhead turtles. It eats algae and invertebrates. In the Pacific, there are two similar species–the Brown Pacific Weed Crab and the Blue Pacific Weed Crab. Not much is known about these creatures but they have the ability to change color to suit their backgrounds and escape being noticed. They are quite small at around 3 inches across, fully grown.
These are the biggest land dwelling crabs. They can weigh up to 4 kg (9.0 lb) and are about the size of a cat. They will eat almost any kind of food they come across, from fruit to dead animals. They are even capable of opening and eating a coconut, hence their name.
Chionoecetes bairdi is a crab species that can be found in the Bering Sea. It is also commonly known as Tanner Crab. Commercially, it is called Snow Crab. It can live over a decade and can weigh as much as 1.8 kg.
Atlantic Rock Crab
Atlantic Rock Crab or Cancer irroratus is a colorful crab species that can be found in the eastern coast of North America. This edible crab is fish commercially.
Jonah Crab or Cancer borealis is a commercially significant crab species that can be found on the Atlantic coast of North America. This crab with strong claws but not very aggressive has been fished on a small scale since the 1970s. Around 1,500 tonnes of Jonah Crabs are being caught annually.
It has unusual shovel-like “nose”, relatively short legs, large orange pinchers. Typically covered in sponges. The sharpnose crab is easily distinguished by its unique wide rostrum (nose, if you will). This crab is often hard to detect as it is usually covered in small invertebrates. There is nothing like t ravelling with friends.
Longhorn Decorator Crab
Orange colored body, with two long and parallel horns. Carapace has small spines. Long walking legs. This little crab is a relatively modest decorator.
Green Shore Crab
A common crab found by beachcombers who turn over rocks. When exposed, this little crab often scampers and hides under the closest rock. The crab in this picture has given up on fleeing and assumed a defensive position. Typically green body with white tipped pinchers. Tiny hairs on legs.
Graceful Kelp Crab
Blue pinchers with orange tips. Bumps on carapace, but no spines. Broad “hook” on first carapace tooth on either side. Medium length horns that have significant space between them and slightly diverge. This crab does decorate, but unlike the graceful decorator crab, it tends to keep the decoration simple and only decorate its rostrum. Also not the blue pincher tipped with orange.