Horse crabs are found from Hokkaidō to South India, throughout Maritime Southeast Asia and south to Australia. In Malay, it is known as ketam bunga or "flower crab". It lives on shallow sandy or muddy bottoms, less than 50 m deep, where it feeds on seaweeds and predates upon small fish, worms and bivalves. The carapace may reach 15 cm (5.9 in) wide, and 7 cm (2+3⁄4 in) from front to back.

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Distribution map

The carapace can be up to 20 cm wide. They stay buried under sand or mud most of the time, particularly during the daytime and winter. The species is commercially important throughout the Indo-Pacific where they may be sold as traditional hard shells, or as "soft shelled" crabs, which are considered a delicacy throughout Asia. The species is highly prized as the meat is almost as sweet as the blue crab, although P. pelagicus is physically much larger.

Snow crab are caught as far north as the Arctic Ocean, from Newfoundland to Greenland in the Atlantic Ocean, and across the Pacific Ocean, including the Sea of Japan, the Bering Sea, the Gulf of Alaska, Norton Sound, and even as far south as California for Chionoecetes bairdi. Fishing for opilio (and rarely bairdi) crab has been the focus of the second half of all four seasons of Deadliest Catch on the Discovery Channel.^[8]

While blue crabs remain a popular food in the Chesapeake Bay area, the Bay is not capable of meeting local demand. Crabs are shipped into the region from North Carolina, Louisiana, Florida and Texas to supplement the local harvest.

The edible crab is abundant throughout the northeast Atlantic as far as Norway in the north and northern Africa in the south, on mixed coarse grounds, mud and sand from shallow sublittoral to about 100 m. It is frequently found inhabiting cracks and holes in rocks but occasionally also in open areas. Smaller specimens may be found under rocks in the littoral zone.^[12]

Edible crabs are exploited commercially throughout their range. It is illegal to catch crabs of too small a size around the coast of Britain, a conservation measure brought in the 1870s. Crabs with a shell diameter of less than 100 mm should not be taken.

They measure as much as 25 cm (9.8 in) in some areas off the coast of Washington, but typically are under 20 cm (7.9 in).^{[Note 2]} They are a popular delicacy, and are the most commercially important crab in the Pacific Northwest, as well as the western states generally.^[15]

They are named after Dungeness, Washington,^[14] which is located approximately five miles north of Sequim and 15 miles east of Port Angeles. The annual Dungeness Crab and Seafood Festival^[16] is held in Port Angeles each October.

Dungeness crab have recently been found in the Atlantic Ocean, far from their known range, raising concern about their possible effects on the local wildlife.^[17]