CARDISOMA GUANHUMI, also known as the BLUE LAND CRAB, is a species of
land crab found in tropical and subtopical estuaries and other
maritime areas of land along the Atlantic coast of the
* 1 Description * 2 Distribution * 3 Diet * 4 Senses * 5 Life cycle * 6 References * 7 External links
The carapace of C. guanhumi can reach sizes up to around 11 cm (4.3 in) and individuals can reach sizes of up to 35 cm (14 in). As with many crab species, males possess dimorphic claws: the larger claw can grow up to around 15 cm (5.9 in) in length, eventually becoming larger than the carapace itself. The eyes are stalked and their colour ranges from a deep blue to a pale grey. Juveniles generally have a brown carapace with orange coloured legs. Females usually appear light gray or white. Adult colours are usually present between 80 g (2.8 oz) and 180 g (6.3 oz). Individuals of the species can weigh over 500 g (18 oz).
Cardisoma guanhumi is found throughout estuarine and other coastal
regions of the Caribbean, and along the Atlantic coast of Central and
South America (south to Brazil). In the United States it can be found
in coastal areas of the
Gulf of Mexico
Cardisoma guanhumi is omnivorous , collecting and eating leaves and fruits close to its burrow whilst also eating insects and carrion. Like many crabs, this species is cannibalistic . They move in the shade during the day and will eschew moving in prolonged direct sunlight to feed at night instead.
Cardisoma guanhumi finds its food using light and sound detectors.
Experiments show that crabs can be drawn out of their burrows to
investigate the sound of falling fruit, once out they initiate a
search for food. Predatory behavior is released in these crabs by
detection of small moving objects. Crabs in the genus
able to detect small vibrations on the ground within the range of
10–1500 Hz and 70 dB.
Guarding the burrow A juvenile blue land crab showing a different coloring
The reproductive cycle is closely linked to seasonal weather patterns
and lunar phase. Heavy rains in the spring initiate migrations. When
this occurs, C. guanhumi begins to gain weight, as more food is
consumed and gathered for the first few weeks of the migratory period.
Males mate with mature females during this time.
C. guanhumi is a slow-growing species compared to most other crabs. It requires more than 60 molts – roughly three times more than other species of crab - to reach its full size. The crab will generally seal the exit to its burrow using mud, 6–10 days before it molts, in order to protect itself from predators. (After molting , crabs are more vulnerable to attack as their shell has not yet hardened.)
* ^ A B Helmut Debelius (2001). Crustacea - Guide of the World (2nd ed.). Frankfurt: IKAN Unterwasserarchiv. * ^ A B C D E F G H K. Hill (July 25, 2001). " Cardisoma guanhumi". Smithsonian Marine Station at Fort Pierce .