Invertebrates
Ghost Crab
Ocypode · also called ghost crabs, sand crabs
A ghost crab freezes against the dry sand, nearly invisible, then breaks into a sprint fast enough to leave a jogging beachgoer behind before vanishing down a burrow dug well above the tideline. For an animal built so thoroughly for life on land, it still cannot cut its ties to the surf completely — its gills need to stay wet, so every so often the sprinting has to end in a dash back toward the water.
Overview
The ghost crab, genus Ocypode, is a fast-running, pale-coloured crab found on sandy beaches across tropical and subtropical coastlines worldwide. It digs deep burrows above the high tide line and feeds on a wide range of beach organic matter.
Built for land, tied to the tide
Despite its speed and its deep, dry burrows, a ghost crab’s gills still require regular moisture to function, forcing even this thoroughly land-adapted crustacean back toward the surf periodically, a reminder of how recently its lineage made the move away from full aquatic life.
Status
Least Concern — common and widespread across suitable sandy beach habitat worldwide, though beach development and heavy foot traffic can reduce local populations.
Ghost Crab: common questions
How fast can a ghost crab actually run?
A ghost crab is capable of running at considerable speed across open sand, with some species able to reach speeds fast enough to outrun a jogging human over short distances, a combination of speed and manoeuvrability that makes it one of the quickest land-dwelling crustaceans known and genuinely difficult to catch by hand.
If a ghost crab lives on land, why does it still need to visit the water?
A ghost crab breathes using gills that must remain moist to function properly, so despite spending much of its time on dry sand away from the surf, it still needs to periodically return to the water's edge or damp sand to keep its gills adequately wet, making regular contact with moisture essential even for this largely terrestrial crab.
How can a ghost crab make a sound?
A ghost crab can produce a rasping or stridulating sound by rubbing specialised ridges located on its claw against another part of its own body, a form of sound-based communication that the crab uses during territorial disputes or other social interactions with nearby individuals.
Why is it called a ghost crab?
The ghost crab gets its common name from its pale, sandy, almost translucent colouration, which blends closely with dry beach sand and allows the crab to seem to disappear or "ghost" away when it freezes or dashes suddenly across an open stretch of beach, making it appear and vanish with startling speed.