| Ghost crabs | |
|---|---|
| Ocypode quadrata | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Infraorder: | Brachyura |
| Family: | Ocypodidae |
| Genus: | Ocypode Weber, 1795 [1] |
| Type species | |
| Cancer ceratophthalmus Pallas, 1772 |
|
Ghost crabs, also called sand crabs, are crabs of the genus Ocypode, common shore crabs in many countries. Characteristics of the genus include one claw being larger than the other, but this difference is not as marked as in male fiddler crabs.
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Ghost crabs dominate sandy shores in tropical and subtropical areas, replacing the sandhoppers that predominate in cooler areas.[2] They breathe through gills, which they periodically wet with seawater.[2] They must also return to the ocean to release their eggs, which develop into marine larvae.[2]
Adult ghost crabs dig deep burrows, comprising a long shaft with a chamber at the end, occasionally with a second entrance shaft. They remain in the burrow during the hottest part of the day, and throughout the coldest part of the winter.[2] They emerge mostly at night, to feed on mole crabs and coquina clams, although they will also eat a wide range of items, including carrion, debris and turtle hatchlings.[3]
The name "ghost crab" derives from the animals' nocturnality and their pale colouration;[2] only O. gaudichaudii is brightly coloured.[4] The scientific name Ocypode is derived from the Greek roots ocy- ("fast") and ποδός (podos, "foot"), in reference to the animal's speed.[5]
The gait of O. ceratophthalmus alters as its speed increases. It can walk indefinitely using all four pairs of walking legs, occasionally alternating which side leads. At higher speeds, the fourth pair of legs is raised off the ground, and at the highest speeds, the crab runs, using only the first and second pairs of walking legs.[6]
There are 28 species in the genus:[1]