Ghost crab

Ghost crab
Ocypode cordimana Batemans Bay, New South Wales, Australia
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Infraorder:	Brachyura
Superfamily:	Ocypodoidea
Family:	Ocypodidae
Genus:	Ocypode Weber, 1795
Species
See text

Ghost crabs, also called sand crabs, are crabs of the genus Ocypode, common shore crabs in many countries. In the eastern United States, Ocypode quadrata is frequently seen scurrying along beaches between sunset and dawn.

These crabs are called ghosts because of their ability to disappear from sight almost instantly, scuttling at speeds up to 10 miles per hour, while making sharp directional changes. These creatures have two black eyes, with sharp 360° vision which they use to see flying insects and catch them in mid air. The ghost crab, however, cannot see directly up, so it must burrow into the ground to prevent birds from catching it.

The ghost crab tunnels down four feet into the ground at a 45° angle, creating 1-2 inch wide holes, which speckle the beach. At dusk, these crabs will sprint to the ocean in order to obtain oxygen from the water which washes over their gills, and in June, females will release their eggs into the ocean. Ghost crabs hibernate during the winter, holding their breath for six weeks, by storing oxygen in sacs near the gills.

The common ghost crab or smooth-handed ghost crab (Ocypode cordimana) is found on the northern Australian coast from the Kimberley region of Western Australia to New South Wales, being particularly common in New South Wales. It is also found in the Indo-Pacific region.

Characteristics of the genus include one claw being larger than the other, but not as profoundly as for the male fiddler crab.

Species

• Ocypode ceratophthalmus
• Ocypode cordimana
• Ocypode cursor
• Ocypode pallidula
• Ocypode quadrata
• Ocypode ryderi

External references

Australian Department of Environment and Heritage page on Ocypode cordimana