Crabs
These are all so-called "true crabs".
True crabs are crustaceans with extremely reduced tails, which are carried folded under the body. Males are generally larger than females. Presented here are just the most common of many local species. Sizes quoted below are body width. Hermit Crabs are listed elsewhere. They are not closely related.
| AG - antennal gland DG - digestive gland E - eye H - heart HG - hindgut M - midgut | O- oesophagus S - stomach SG - supra-esophageal ganglion TG - thoracic ganglion (nerve) VNC - ventral nerve cord |
A female crab sees a male crab walking in a straight line Amazed by the crab's rare gait, she is smitten. She asks him to marry her, and he happily agrees. The next day, she notices that he is walking normally in a zigzag pattern. She is shocked. She asks him why he is walking in this manner now. He replies, "Baby, I can't be that drunk always, can I?"
These crabs have the last pair of legs modified into paddles, with which they are remarkably fast and agile sideways swimmers. Apart from this, they retain the walking and burrowing abilities of other crabs. Swimming crabs are bad-tempered creatures that aggressively defend themselves. Large ones can pinch very painfully, so handle with care!
Blue Crab ( Blue-claw )
Callinectes sapidus
Profile by Bill Figley
and Ray Townsend
Size:
to 9" across
Range:
Cape Cod to Texas
Habitat:
Bays and estuaries, sometimes found in freshwater, spend their winters in the mud.
More: Swimming Crabs ...
Lumped together here are what might be considered to be "normal" aquatic crabs. There are many other similar types. The claws of many crabs are good eating - break one off and let the crab go, it will grow a new one. Never take both - you'll kill it.
More: Bottom Crabs ...
Spider Crabs Libinia emarginata are scavengers. Although they are fearsome-looking, they are actually slow-moving, and their usual claws-out threat display is mostly bluff. Spider Crabs have relatively small round bodies (to 4"), long legs, and rather weak claws. They are found subtidally to at least 160 ft, on any type of bottom, and are very common in rivers and inlets. They often cover themselves with detritus for camouflage, and can also burrow in soft sediments.
More: Spider Crabs ...
Ocypode quadrata
Uca spp
These small crabs are largely terrestrial. Female Fiddler Crabs lack the huge claw of the male, which is very strong but is used only in dance-like territorial displays. Several species in the area differ mainly by habitat. Fiddlers prefer marshes and stream banks, where huge colonies riddle the peat with tunnels near the waterline. Almost entirely terrestrial, you will find Ghost Crabs skittering across the beaches at night. Placed in the water, they may even drown! Both grow to a body size of approximately 1 inch.
More: Beach Crabs ...
These animals are lumped together here because they all have hard external shells. Crustaceans and Mollusks are not closely related at all. This is more of a restaurant classification than a scientific one.
- American Lobster
- Crabs ...
- Other Crustaceans ...
More: Marine Shellfish ...