Cardisoma guanhumi

Distinguished from other Cardisoma species by geographic range (Atlantic coast of Americas only) and adult coloration pattern. C. carnifex (Indo-Pacific) and C. hirtipes (Indo-Pacific) occupy different ranges. Within range, distinguished from the blackback land crab (Gecarcinus lateralis) by burrow depth and habitat preference—C. guanhumi constructs deeper burrows (to water table) in lower supratidal zones versus G. lateralis in higher intertidal areas. Color change with size is diagnostic: smaller crabs orange/brown, larger crabs blue/gray.

Large-bodied terrestrial crab with carapace width reaching up to 15 cm and body mass exceeding 500 g. Carapace color varies ontogenetically and sexually: juveniles typically brown with orange legs; adult males deep blue to dark brown with dimorphic claws where the larger cheliped may exceed carapace width; adult females pale gray to white. Stalked eyes. Sexual maturity in coloration generally achieved between 80–180 g body mass.

Coastal supratidal and terrestrial habitats adjacent to estuaries, mangroves, and maritime forests. Constructs deep burrows in sandy-loam soils that extend to the water table, providing access to moist substrate and enabling survival away from surface water. Found in natural coastal scrub, mangrove edges, and increasingly in human-modified environments including urban areas and agricultural croplands where suitable burrowing substrate persists.

Atlantic coast of tropical and subtropical Americas: from Brazil and Colombia north through Caribbean islands, Gulf of Mexico, Bahamas, and Bermuda to northern limit at Ponce Inlet and Vero Beach, Florida. Northern range limited by winter water temperatures below 20°C affecting larval survival.

Reproductive migrations triggered by heavy spring rains. In Florida, spawning season extends June–December peaking October–November; Bahamas July–September; Venezuela July–November. Nocturnal surface activity year-round in suitable climates; diurnal movement avoided due to desiccation risk.

Omnivorous: consumes leaves, fruits, and seeds near burrow entrances; actively preys upon insects and other small invertebrates; scavenges carrion. Cannibalism documented. Food detection mediated by light and sound sensors; crabs respond to auditory cues of falling fruit and ground vibrations (10–1500 Hz, 70 dB threshold).

Slow-growing and long-lived: requires >60 molts to reach maximum size, approximately three times more than comparable crab species. Pre-molt burrow sealing with mud occurs 6–10 days before ecdysis to reduce predation risk during vulnerability period. Reproduction internal; females carry fertilized eggs externally July–August. Eggs hatch after ~2 weeks into planktonic larvae requiring immediate release to saltwater. Larval development: five zoeal stages and one megalopa stage; laboratory development time 42 days from hatching to first crab stage, potentially shorter in wild. Multiple spawns possible annually.

Nocturnal foraging to avoid desiccation; diurnal activity restricted to shaded microhabitats. Constructs and maintains permanent burrows with characteristic architecture including inclined entrance tunnel and large terminal chamber. Pre-molt burrow sealing behavior reduces predation risk. Reproductive migrations occur during spring rains with mass movements of adults toward coastal release sites. Acoustic and vibrational sensitivity enables detection of food resources and predators.

Keystone burrower in low-latitude supratidal habitats; burrowing activity modifies soil structure, drainage, and aeration in coastal ecosystems. Large terminal chambers serve as organic matter repositories and microhabitats. Potential prey for larger vertebrates; carrion consumption contributes to nutrient cycling.

Historically and currently exploited as food resource throughout range; meat high in protein (14–22.6%) and minerals with low lipid content. Subject to fisheries regulations including closed seasons, minimum size limits (64 mm carapace width in Puerto Rico), and protected area prohibitions. Population declines from overharvesting and habitat loss have prompted conservation listings in Puerto Rico, Colombia, and other jurisdictions. Increasing occurrence in urban and agricultural landscapes suggests adaptability to human-modified environments, though long-term size reduction in harvested populations indicates exploitation pressure.

• Gecarcinus lateralissympatric blackback land crab; distinguished by shallower burrows in higher intertidal zones and different color pattern (black carapace with purple claws)
• Cardisoma carnifexcongeneric species of Indo-Pacific distribution; allopatric but morphologically similar; distinguished by range
• Cardisoma hirtipescongeneric Indo-Pacific species; allopatric; distinguished by range and habitat preferences

• land crab
• terrestrial crab
• burrowing crab
• omnivore
• nocturnal
• mangrove-associated
• fisheries species
• threatened species
• keystone species
• urban adapter

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Thin Layer Drying Kinetics of Salt Water Crab (Cardisoma Guanhumi)
• The Burrow Habitat of the Land Crab, Cardisoma guanhumi (Latreille)
• Observations On the Feeding Behavior of Cardisoma Guanhumi (Latreille) in Southern Florida1)
• Long-term monitoring of crab Cardisoma guanhumi (Decapoda: Gecarcinidae) captures in Jobos Bay Estuary, Puerto Rico
• MORPHOMETRY OF BLUE LAND CRAB (CARDISOMA GUANHUMI) BURROWS: ICHNOLOGICAL CONTEXT AND PALEOENVIRONMENTAL IMPLICATIONS
• Parámetros de crecimiento de Cardisoma guanhumi en el departamento del Magdalena, Colombia
• Distribution of calcium in the land crab Cardisoma guanhumi during shell wound recalcification
• Variation in the adult sex ratio and morphological traits of Cardisoma guanhumi (Latreille, 1828) in contrasting habitats in the southwest of the Gulf of Mexico
• Is the threatened land crab Cardisoma guanhumi conquering human‐dominated systems?
• Variation in the Adult Sex Ratio and Morphological Traits of Cardisoma guanhumi (Latreille, 1828) in Contrasting Habitats in the Southwest of the Gulf of Mexico.