On many tropical and subtropical beaches, a small, pale runner darts across the sand at dawn and dusk — the ghost crab. Named for its pale color, rapid movements and sudden disappearances into sand burrows, the ghost crab is a familiar yet little-noticed guardian of the coastline. From Cox’s Bazar to Kuakata, these tiny crustaceans play outsized roles in keeping shorelines clean, signaling beach health, and shaping coastal ecology.

Size and appearance
Ghost crabs are compact — typically 2–5 cm across the carapace — with coloration that blends into sandy shorelines: pale grey, white or sandy brown. Their stalked eyes rise above the body on long eyestalks, giving them excellent vision for spotting predators and prey. One claw is usually larger and sturdier than the other, used for feeding and defense.

Speed and behavior
Despite their small size, ghost crabs are fast: observers report startling bursts of speed that let them cover large distances across loose sand in seconds. They are primarily nocturnal, emerging at dusk or dawn and becoming especially visible during full-moon nights. Highly wary of light and noise, they quickly vanish into burrows at the first sign of disturbance.

Burrows and habitat
These crabs live in deep, vertical burrows dug into the dry part of the beach. Burrow depths can reach up to a metre and provide shelter from heat, predators and high tides. The presence, depth and density of burrows are often used by scientists as indicators of a beach’s ecological condition.

Diet and ecological role
Ghost crabs are omnivores and opportunistic scavengers. They feed on dead fish, small invertebrates, algae and organic debris washed ashore. By consuming carrion and decomposing material, they help keep beaches clean and reduce foul odors. Their feeding and burrowing activities also aerate beach sands and influence nutrient cycling — important processes for shoreline ecosystems.

Reproduction and life cycle
Breeding generally occurs in warmer months. Females release hundreds of eggs, which hatch into planktonic larvae that spend time in the sea before returning to the shore and maturing into juvenile crabs. This marine-to-terrestrial life cycle ties ghost-crab populations closely to both coastal and nearshore ocean conditions.

Threats and conservation
Ghost crabs face growing pressures from human activities: coastal development, artificial lighting, beachfront pollution and heavy foot or vehicle traffic can destroy burrows and alter behavior. Light pollution, in particular, disrupts nocturnal activity and can reduce feeding and breeding success. Scientists recommend reducing beachfront lighting, restricting vehicle access in sensitive areas, and conserving undisturbed stretches of sand during breeding seasons to protect these animals.

Why they matter
Though small, ghost crabs are valuable ecological indicators. Healthy, active populations point to functioning beach ecosystems; declines may warn of habitat degradation. Protecting ghost crabs means protecting the broader coastal environment they help sustain.

What visitors can do
Beachgoers can help by avoiding trampling dune and burrow areas, sticking to marked paths, disposing of waste responsibly, and supporting local efforts to limit night-time lighting on beaches. Simple changes in behavior can preserve both the delicate life at the shoreline and the natural beauty that draws people to it.