A Few Random Things About Ghost Crabs

I've had a few questions lately about ghost crabs, so I thought I might put down a few words about them.














A true crab, the ghost crab belongs in the family Ocypodidae, which also includes the fiddler crabs. Worldwide, there are roughly 20 species of ghost crabs, but O. quadrata is the only one found on the east coast of the United States. The species is a small straw-colored or grayish-white crab, measuring about 5 cm (2 inches) across the back at maturity. Ocypode has
the greatest terrestrial adaptation of any crab in South Carolina, returning only occasionally to the water to wet its gills. It can also moisten its gills by extracting water from damp sand, using fine hairs near the base of its walking legs to wick ground water up onto the gills through
capillary action. Despite this semi-terrestrial existence, the ghost crab’s link to the sea is a critical one that provides not only moisture for its gills, but also the necessary means for development of larvae that are hatched from eggs that the females release at the water’s edge.

Although rarely seen in the winter, during the rest of the year O. quadrata is common or abundant on outer beaches and on more protected harbor beaches near coastal inlets along the coast of South Carolina . Rarely has the species been the target of quantitative study in our state and, despite its abundance, nothing is known of trends in its population status here. Quantitative measures of the population size in South Carolina are nonexistent, although estimates based on burrow counts or nocturnal transect counts could provide a
good measure of abundance. Such efforts have not been undertaken across a wide geographic area within the state.

Ghost crabs are largely nocturnal in nature and it is rare to catch a glimpse of them during the
day. Most feeding activity occurs at night, which reduces predation by visual predators like shorebirds and gulls that might otherwise be capable of exerting considerable pressure on populations of this species. In the event that they do leave their burrow during daylight, their ability to change color to match the sand where they live lessens their chances of being seen on such a foray.

The burrows dug by ghost crabs may be up to 1.3 m deep (4 feet). Their habits of periodically
closing the burrow opening with sand during the hottest part of the day and of remaining within
the burrow through the colder months provide sufficient protection from the climatic extremes
that fully aquatic species rarely encounter. These burrows, which take different shapes beneath
the sand, are found from near the high tide line to a distance as great as 400 m (0.25 mile) from
the ocean. A distributional gradient based on crab age is typical for this species, with younger
crabs generally burrowing closer to the shore than older individuals

Found { http://www.dnr.sc.gov/cwcs/pdf/Ghostcrab.pdf}