PANZERWELTEN-FORUM

by Ollie (Beastiependent)
translated by Ulli Bauer

Scientific name: Gecarcinus lateralis

Trivial names: Halloween Crab (also: Blackback Land Crab, Red Land Crab, Bermuda Land Crab, Moon Crab)

Systematics: Domain: Eucaryota, kingdom: Animalia, subkingdom: Metazoa (multiple-celled animals), Eumetazoa (true tissue), grade: Bilateria, branch: Protostomia, infrakingdom: Ecdysozoa (molting animals), phylum: Arthropoda (jointed-leg invertebrates), subphylum: Crustacea, class: Malacostraca (higher crustaceans), superorder: Eucarida, order: Decapoda (ten-legged crayfish), suborder: Pleocyemata, infraorder: Reptantia, section: Brachyura (true crabs), superfamily: Grapsoidea, family: Gecarcinidae (land crabs), genus: Gecarcinus, species: Gecarcinus lateralis

Origin/range: West Atlantic (Bermuda, Antilles, Florida, American East coast from Central America to Guyana, west coast of Mexico to Peru)


more pics: http://www.panzerwelten.de/v/Gecarcinus/Halloween/


Description: Carapace, legs and claws orange, back carapace with black spot. There is also a white variant as well as color variations of grey and purple.

Sex differences: Typical for crabs, the males have a narrow, pointed abdominal apron, the female's apron is wide and rounded; moreover, the female's claws are smaller.


Males (l.) have a narrower abdominal apron, females a wide one.

Size: Carapace up to 10 cm wide.

Life span: At least 10 years.

Temperature: tropical (20 to 28 °C).

Tank size/stock: In a 1 meter tank a pair to up to four specimens (given that the tank is well-structured!)

Tank decoration: Terrarium with sand and maybe terrarium humus for burrowing, things to hide and climb on (wood, rocks), moss, nonpoisonous plants (e.g. no ivy), tree leaves (as hideout and food). A small water part (with fresh, brackish or sea water) is possible, but not necessary. A small bowl with water or a little fountain are as good as spraying the terrarium with water from time to time. These land crabs do not need access to water! They take the humidity they need from moist substrate and actually avoid water!



Food: Typical for crabs, they are omnivores.
• Leaves (the main staple of many crabs in nature; mostly oak and beech are fed, however, all European broadleaved tree leaves are possible, also Indian almond leaves), muck, water plants
• Vegetables/fruit: nearly all vegetables and fruit are suitable (peas, lettuce, cucumber, apple, zucchini, pear, banana, grapes, tomato, Brussels sprouts, bell peppers) except for parsley and beans or other kinds that contain Prussic acid or copper; carrots (boiled); potato and rice (boiled) or noodles (uncooked? Don't leave these in the tank for too long a time though, they can be the cause of turbid water and finally lead to a bacteria bloom and oxygen depletion); no citrus fruit due to their high acid content
• Dry food: Catfish tabs, fish (flake) food, food pellets, rabbit, guinea pig and chinchilla food pellets (without copper!), Spirulina tabs, crayfish tabs, Gammarus
• Frozen food: Black, glass and blood worms, Cyclops, brine shrimp, clam meat
• Live food: Earthworms (it's best to cut them into pieces though, or else these worms might burrow in the substrate, possibly also under water, die and rot there unnoticed until it's too late)
• Meat (rarely): Chicken bones with meat rests (rinsed well to prevent too much fat from getting into the terrarium)
• Fish: deep-frozen smelts et.al., tuna fish, sardines, herring etc. fresh or from a can (in their own juice, not in oil)
• Calcium: cuttlebone, smashed eggshells or powdered calcium in self-made food sticks



Behavior: Not very aggressive towards conspecifics, often sit in their burrows or caves for hours or even days, like to burrow (not down to the ground water). Nocturnal (with exceptions), not during the rainy season (in nature).



Reproduction: Seasonal mating, depending on the moon. The larvae are released into the sea after about three weeks and need at least 29 days there to grow to small crabs, going through several zoea and megalopa stages, then return to land. They tolerate a salinity of 50 to 125%, roughly 15 to 40 g of salt per liter. They have already been bred in the laboratory.

Socialization: none, except with Gecarcinus ruricola and G. quadratus (also called Halloween crab).



Additional information:
• This species is sometimes mistaken for Gecarcinus ruricola, which are also called Halloween Crab (or Barbados Moon Crab, Black Crab, Black Land Crab, Purple Land Crab, Carribean Black Land Crab) and have a comparable range. These species are so similar regarding their requirements that they even might be kept in a (sufficiently large) tank together.

• They are land crabs, the most terrestrial of all. Adult animals spend their entire life on land. In nature, they live up to 30 km away from the sea and at heights of over 300 m. They have adapted to life on land so well that they even drown in water and only take to the sea shore for releasing their larvae. This is the result of their significantly smaller gill surface (only 15% of that of aquatic crabs) that thus cannot take up enough oxygen any more in the water (only 1/6 to 1/7 of the air's oxygen content).

• If possible they ought to be given an opportunity to burrow. When kept appropriately, they can only be observed at night, though, only a few are active during the day. G. lateralis prefer given hideouts as caves or holes in rocks, whereas G. ruricola rather burrows.

• For this species, science has described a communication system hitherto unknown in land crabs (however, this behavior has been observed in land hermit crabs, Coenobita sp., belonging to the Anomurans). The information whether the animal is threatening, appeasing or displaying is transmitted by acoustic pulsation via the substrate. This pulsation is produced by stridulation. That usually describes a certain way insects and spiders produce sounds by rubbing two mobile body parts together. It is still in the dark which body parts these crabs use to make sounds.

• Before and after molting, these crabs retreat to their burrows for a period of up to several weeks, during which they don't eat and are, all in all, very inactive. In nature they eat the empty exuvia in their burrow in order to get the calcium they need for forming a new carapace. After molting, crabs, like all crustaceans, are quite soft ("soft crayfish") and need time without being disturbed in order to let their new carapace harden entirely. In order to prevent conspecifics from injuring them they thus need sufficient places to hide. When molting, these animals can - like all crustaceans - replace lost or self-amputated limbs.

• Unique: After molting, crabs of this species are able to "inflate" themselves with intestinal gases in order to stabilize the new, still-soft, larger carapace until it has hardened. Other species are simply known to "pump" themselves up with water. With the help of these intestinal gases, G. lateralis can even move in this phase.

• G. lateralis do not compare to Cardisoma regarding their aggressiveness or their territoriality, i.e. they can easier be kept in groups and it is not compulsive to keep them alone in a tank. However, carapace widths of up to 9 cm are accounted for, thus an adult crab can easily reach a legspan of nearly 30 cm; this should always be kept in mind when choosing the tank. The better the terrarium is structured (many hideouts and possibilities to burrow, several levels, moss, leaves, wood etc.), the more animals can be kept in it. As a guideline you take two to four of these crabs to a 100 cm long tank, whereas the number of females should always exceed that of the males.

• As all crabs, Gecarcinus lateralis are good climbers, thus the terrarium cover has to close off the tank securely.

LINKS:
• This species datasheet as pdf file
• Breathing of Gecarcinus lateralis (in English)
• Density and population structure (in English)
• Behavior and growth of the land crab Gecarcinus lateralis (in English, 26,5 MB ? 150 pages-PDF!)
• Morphological and physiological aspects of coloration in the land crab Gecarcinus lateralis (in English)
• Spiegel-Online: Exoskeleton – intestinal gas helps crabs harden (in German)


These crabs are usually very secretive and just leave their burrows at night.