Painted Ghost Crab

Painted ghost crabs have been described as opportunistic feeders in three different behaviors: as deposit feeders, scavengers, and predators. Typical food includes organic matter within sand, live organisms, and dead matter from both ocean and terrestrial sources. When adults, painted ghost crabs typically become specialized in deposit feeding and sift through the sand to find organic material as food. They develop specialized claws (or chelae), called truncated claws, which are used to forage in the sand as a makeshift shovel. The presence of truncated claws has been shown to allow a broader diet as the crabs are able to feed on both animals and diatoms. While the major chela of the painted ghost crab is typically the left, the major chela of another crab within the same genus, O. quadrata, has a 1:1 ratio between right and left cheliped laterality.

Both male and female painted ghost crabs dig burrows. The burrows act as important protection for the painted ghost crab, allowing them to avoid predators, rapid environmental changes, and other territorial crabs of the same species. The creation of the burrows includes characteristic behaviors and utilize both wet and dry sediment. O. gaudichaudii have been observed disposing of unwanted or unused sediments when building burrows with a kick, dump, or tamp behavior. Sand dug from the burrows are deposited by kicking or dumping while the deposited sand is manipulated by tamping. Tamping involves applying pressure to the sand using the ambulatory legs and all residents of tamped burrows are males. The majority of females are found in dumped burrows, but some can be found inhabiting kicked burrows. The varying sand disposal behaviors create differing burrow patterns and characteristics.

Adult painted ghost crabs deposit feed on microscopic organic matter found in the sand, reaching their food by digging or foraging through the sand. Juveniles exhibit predatory feeding and commonly prey on small arthropods. All crabs of the Ocypode genus use their mandibles to break food into smaller pieces to aid in ingestion. When adults, painted ghost crabs become specialized in deposit feeding and sift through the sand to find organic material as food. After ingesting the organic matter, the non-digestible particles are formed into pellets that are then excreted from the buccal cavity.

Ghost crabs within the genus Ocypode can be used as bioindicators to the effects of human presence and alterations on coastal environments. This is because they are apex predators in their environment, are present at unvegetated beaches and dunes, and their changes in population and density are easy to calculate by counting the number of burrow holes present and measuring the size of the openings. Human interaction on beaches occupied by painted ghost crabs significantly impacts the habitat's population density. Specifically, mechanical cleaning methods (commonly involving the filtering of sand using motorized vehicles) significantly decrease the density of ghost crabs.