Seychelles has an incredible 32 species of land, shore, brackish water and freshwater crabs. These do not include all the marine crabs that inhabit the sea.
Most people are familiar with the ghost crabs that dig their burrows along the shoreline, and scurry around on the hunt for food, when they think they’re not being watched. Ghost crabs are common shore crabs in many countries. A true crab, or brachyuran, the ghost crab belongs to the family Ocypodidae, which also includes the fiddler crabs. Worldwide, there are roughly 20 species of ghost crabs.
The ghost crab is found on sandy beaches throughout Seychelles. It is a relatively large crab with a pale cream-grey colour and with pronounced “horns” above the eyes. Ghost crabs are largely nocturnal but on less disturbed islands it is active during the day. If they do leave their burrow during daylight, their ability to change colour to match the sand where they live lessens their chances of being seen on such a foray.
When threatened it retreats to the safety of its burrow, running rapidly across the sand. Adult ghost crabs dig deep burrows, comprising a long shaft with a chamber at the end, occasionally with a second entrance shaft.
Ghost crabs are opportunistic scavengers, feeding on living and dead plants and animals including turtle eggs and hatchlings. Feeding mostly occurs at night, which reduces predation by visual predators like shore birds and gulls that might otherwise be capable of exerting considerable pressure on populations of this species.
(Photo credit: Martijn-Hammers)