Caribbean hermit crab
715458
225240966
2008-07-12T17:18:24Z
Invertzoo
4863204
removed common name list from synonym category in taxobox. Synonym is only for other Latin names applied to the same species
{{Taxobox
| name = Caribbean hermit crab
| image = Hermit-Crab.JPG
| image_width = 220px
| regnum = [[Animal]]ia
| phylum = [[Arthropod]]a
| subphylum = [[Crustacean|Crustacea]]
| classis = [[Malacostraca]]
| ordo = [[Decapoda]]
| subordo = [[Pleocyemata]]
| familia = [[Coenobitidae]]
| genus = ''[[Coenobita]]''
| species = '''''C. clypeatus'''''
| binomial = ''Coenobita clypeatus''
| binomial_authority = ([[Johan Christian Fabricius|Fabricius]], 1787)
}}
The '''Caribbean hermit crab''' ('''''Coenobita clypeatus'''''), also known as the ''tree crab'', the ''tree-climbing crab'', the ''[[soldier crab]]'', and the ''purple pincher'', is a species of land [[hermit crab]] which lives in the [[Arabian Sea]], the [[Caribbean Sea]], southern [[Florida]], [[Venezuela]], and the [[Bermuda Islands]].
[[image:Crabitat.JPG|thumb|left|Suitable "crabitat"]] This species is commonly sold in the United States as a pet. The last of its common names is due to the distinctive purple claw. In captivity they can live to be over 30 years old (and over 40 years in exceptional cases).
Caribbean hermit crabs are [[omnivorous]] [[scavenger]]s who live in colonies of 100 or more in inland areas, and who like to hide in caves or the roots of a tree. They prefer a [[relative humidity]] level between 70% and 78%, and a temperature of 24[[Celsius|°C]] (75[[Fahrenheit|°F]]).
[[image:CoenobitaClypeatus.JPG|thumb|left|Caribbean Hermit Crabs, like other crabs, are [[nocturnal]]]]
==Physical description==
[[Image:Coenobita_clypeatus1.jpg|thumb|left|''Coenobita clypeatus'']]
''Coenobita clypeatus'' is a member of the phylum [[Arthropod]]a and the class [[Malacostraca]]. They can be 17 [[millimetre|mm]] in length. The color varies from a pale red to a dark brown or burgundy.
The eyestalks are round and white, with a black or brown stripe on the bottom. The eyes are oval in shape. The abdomen is short and fat. There are four walking legs, four tiny legs to hold the shell in place, a small pincher, a large purple pincher, and four [[Antenna (biology)|antennae]].
Although these [[hermit crab]]s live on land, they have [[gills]], rather than [[lung]]s. The high [[relative humidity]] of their native environments, plus water carried in the shell, allows their modified gills to remain wet and thus to function properly in extracting oxygen from the air.
==Anatomy==
<gallery>
image:Hermit Crab Eye Stalks.jpg|Eyes
Image:Hermit Crab Gills.jpg|Modified Gills
image:Hermit Crab Abdomen.JPG|Abdomen
image:Shell-Legs Hermit Crabs.jpg|4th leg that grabs the shell
Image:6th legs Hermit Crab.jpg|5th leg that grabs the shell
image:Abdomen-thorax Hermit Crab.JPG|Abdomen-Thorax Connection
Image:Mouth-Hermit crab.jpg|Mouth and antennae connection
image:Hermit crab claws.JPG|Claws (pincers)
</gallery>
==Shell usage and shell fights==
The land [[hermit crab]] uses a [[animal shell|shell]] to protect its delicate body. The shell is sometimes that of a land [[snail]] when it is young, but is usually that of a marine snail. When a marine snail dies, the soft parts decompose or are eaten and the empty shell often washes up onto the shore. The hermit crab can then find and occupy the shell. Larger shells are necessary as the crab grows, but that growth is quite slow.
[[image:Crab-Shells.JPG|thumb|left|Hermit Crab [[Shell]] Variety]]
Hermit crabs are very particular about their shells. Shell switching is not uncommon as the crab searches for the perfect shell. A desired characteristic of a shell is an opening about the size of the large claw, plus about 2½–3 mm (1/10 [[inch|in]] to 1/8 in) all around (more for larger crabs). When threatened, the crab withdraws into the shell and blocks the entrance with the large claw.
Fierce shell fights can occur when the shell supply is not adequate. The loser often dies since many hermit crabs will not release their grip on their shell until they are torn apart. The loss of limbs in shell fights is common, but may not result in death especially since the hermit crab can choose to drop ([[autotomy|autotomize]]) a limb to disengage from the conflict.<br><br><br>
===Shells used by ''Coenobita clypeatus''===
When choice of shells is available, ''C. clypeatus'' seems to prefer intact undamaged shells with [[circle|circular]] or [[oval]] openings and a smooth [[mother-of-pearl]] interior. However in a pinch, they will use whatever they can find that they can fit into, even discarded, man-made items such as plastic glasses, broken bottles or tiny one-person jam jars.
Some of the snail (class [[Gastropoda]], phylum [[Mollusca]]) shells with circular/oval openings available for their use in the wild include :
*Superorder [[Vetigastropoda]] - Order under revision
:*turban shells (genus ''[[Turbo (gastropod)|Turbo]]'', family [[Turbinidae]]) - Examples:
::*Filose Turban (''Turbo cailletii'') - Region: Western Atlantic Ocean - [http://zipcodezoo.com/animals/t/turbo_cailletii.asp ZipCodeZoo entry] - [http://www.gastropods.com/0/Shell_2440.html Picture] - [http://www.gastropods.com/0/Shell_2440.html Picture]
::*Channeled Turban (''Turbo canaliculatus'') - Region: Western Atlantic Ocean - [http://zipcodezoo.com/animals/t/turbo_canaliculatus.asp ZipCodeZoo entry] - [http://www.gastropods.com/6/Shell_1576.html Picture]
::*Chestnut or Knobby Turban (''Turbo castanea'') - Region: Western Atlantic Ocean - [http://zipcodezoo.com/animals/t/turbo_castanea.asp ZipCodeZoo entry] - [http://www.shellmuseum.org/Sanibel/shells_castanea.html Picture]
:*West Indian Topshell shells (''[[Cittarium pica]]'', family [[Trochidae]] - was ''Turbo pica'') - also called the Magpie, the West Indian Topsnail, or erroneously the West Indian Whelk. Over fishing of this snail (Bermuda) has been known to negatively effect the Caribbean hermit crab population. - Region: Indonesia, Bermuda - [http://zipcodezoo.com/animals/c/cittarium_pica.asp ZipCodeZoo entry] - [http://www.gastropods.com/4/Shell_24.html Picture]
*Superorder [[Caenogastropoda]] - Order [[Sorbeoconcha]]
:*periwinkle shells (genera ''[[Littorina]]'', ''[[Littoraria]]'', or ''[[Echinolittorina/Nodilittorina]]'' ; family [[Littorinidae]]) - Examples:
::*White-Spotted Periwinkle (''Echinolittorina/Nodilittorina meleagris'') - Region: N.America, Western Atlantic Ocean - [http://zipcodezoo.com/animals/n/nodilittorina_meleagris.asp ZipCodeZoo entry] - [http://www.gastropods.com/4/Shell_1804.html Picture]
::*Dwarf Brown Periwinkle (''Echinolittorina/Nodilittorina mespillum'') - Region: N.America, Western Atlantic Ocean - [http://zipcodezoo.com/animals/n/nodilittorina_mespillum.asp ZipCodeZoo entry] - [http://www.gastropods.com/5/Shell_1805.html Picture]
::*Mangrove Periwinkle (''Littoraria angulifera'') - Region: North America, Western Atlantic Ocean - [http://zipcodezoo.com/animals/l/littoraria_angulifera.asp ZipCodeZoo entry] - [http://www.gastropods.com/3/Shell_1803.html Picture]
::*Common Periwinkle (''Littorina littorea'') - Region: North America, Caribbean, Europe, India, etc. - [http://zipcodezoo.com/animals/l/littorina_littorea.asp ZipCodeZoo entry] - [http://www.gastropods.com/5/Shell_995.html Picture]
:*"tulip shell" shells (genus ''[[Fasciolaria]]'', family [[Fasciolariidae]]) - Examples:
::*Yellow Tulip Shell (''Fasciolaria bullisi'') - Region: Western Atlantic Ocean - [http://zipcodezoo.com/animals/f/fasciolaria_bullisi.asp ZipCodeZoo entry] - [http://www.gastropods.com/3/Shell_3343.html Picture]
::*Hunter's Tulip Shell (''Fasciolaria lilium hunteria'') - Region: Western Atlantic Ocean - [http://zipcodezoo.com/animals/f/fasciolaria_lilium_hunteria.asp ZipCodeZoo entry] - [http://www.gastropods.com/9/Shell_939.html Picture]
::*Banded Tulip Shell (''Fasciolaria lilium tortugana'') - Region: the Americas - [http://zipcodezoo.com/animals/f/fasciolaria_lilium_tortugana.asp ZipCodeZoo entry] - [http://www.gastropods.com/6/Shell_5746.html Picture]
::*True Tulip Shell (''Fasciolaria tulipa'') - Regions: Americas, India, etc. - [http://zipcodezoo.com/animals/f/fasciolaria_tulipa.asp ZipCodeZoo entry] - [http://www.gastropods.com/0/Shell_940.html Picture]
:*nutmeg shells (genus ''[[Trigonostoma]]'' ; family [[Cancellariidae]]) - Example:
::*Rugosa Nutmeg (''Trigonostoma rugosum'') - Region: Florida, E.Pacific, Western Atlantic - [http://zipcodezoo.com/animals/t/trigonostoma_rugosum.asp ZipCodeZoo entry] - [http://www.gastropods.com/6/Shell_21466.html Picture]
:*tun shells (genus ''[[Tonna_(gastropod) | Tonna]]'', family [[Tonnidae]]) - Examples:
::*Atlantic Spotted Tun (''Tonna maculosa'') - Region: the Americas, Africa - [http://zipcodezoo.com/animals/t/tonna_maculosa.asp ZipCodeZoo entry] - [http://www.gastropods.com/7/Shell_1497.html Picture]
::*Atlantic Partridge Tun (''Tonna pennata'') - Region: the Americas, Western Atlantic Ocean - [http://zipcodezoo.com/animals/t/tonna_pennata.asp ZipCodeZoo entry] - [http://www.gastropods.com/2/Shell_11632.html Picture]
:*King's Crown Conch shells (''[[Melongena corona]]'', family [[Melongenidae]]) - Region: Western Atlantic Ocean - [http://zipcodezoo.com/animals/m/melongena_corona.asp ZipCodeZoo entry] - [http://www.gastropods.com/0/Shell_1010.html Picture]
*Superorder under revision - Order [[Pulmonata]] - have developed lungs, rather than gills
:*Haitian Tree Snail shells [also called "Candy Striped" or "Rainbow" shells] (''[[Liguus virgineus]]'', family [[Orthalicidae]]) - Region: Cuba - [http://zipcodezoo.com/animals/l/liguus_virgineus.asp ZipCodeZoo entry] - [http://www.naplesseashellcompany.com/candy_striped_snail_shells.htm Picture]
==Growth and molting==
[[Image:Caribbean hermit crab getting ready to molt.JPG|thumb|right|Caribbean hermit crab digging under a dish and getting ready to molt]]
The Caribbean hermit crab, like all species of hermit crabs, grows through a strenuous and hazardous process called [[ecdysis|molting]] where the [[exoskeleton]] of the animal is shed and a new, soft exoskeleton is exposed from beneath. A molt also allows the crab to regrow lost [[appendage]]s. The smallest Caribbean hermit crabs will molt many times per year, while the largest (about the size of a baseball) may only molt once every 18 months.
Before a molt, the hermit crab will attempt to eat enough to survive the molting period. It will obtain [[sea salt]] from [[Seawater|salt water]] to aid in shedding the old exoskeleton and will store a supply of water. The crab may even seek out a smaller, tighter shell for easier digging or a larger shell for room to shed. Normally the molt is started by digging down into the moist substrate (with its shell) and creating a little cave. There total darkness triggers the secretion of the molting hormone [[ecdysone]].
Over a period of up to three months (larger crabs require the most time),
* the buried, molting crab sheds the old exoskeleton in a process called [[ecdysis]],
* lost appendages may be regrown (completely or partially),
* the new exoskeleton hardens,
* the old exoskeleton is eaten, in order to reuse the [[calcium]] and other nutrients,
* the crab regains its strength and returns to the surface.
Sometimes the land hermit crab will molt on the surface where other crabs may eat the shed exoskeleton or even kill the defenseless, molting crab. Circumstances that may cause a surface molt include illness, or the lack of a substrate in which the crab can bury itself.
==Land hermit crab reproduction==
Female land hermit crabs release fertilized eggs into the ocean where the salt water causes them to hatch. The hatchlings live in the ocean until their [[gill]]s mature enough to be able to extract [[oxygen]] from air.
Once on land, the hermit crab begins to drink [[fresh water]], but still requires [[Seawater|salt water]] ([[sea salt]]) for functions like molting. After the last developmental molt, the modified gills lose the ability to process water and the crab can [[drown]] if trapped under water.
Captive ''C. clypeatus'' will not breed in an indoor environment, but have done so in an outdoor enclosure. None of the young lived past 10 days.
==External links==
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{{dmoz|Recreation/Pets/Exotic/Invertebrates/Arthropods/Hermit_Crabs/|Hermit Crabs}}
==References==
{{Commons|Coenobita clypeatus}}
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*{{cite journal | quotes=no|author=Nieves-Rivera, Á. M. & E. H. Williams, Jr. |year=2003 |title=''Coenobita clypeatus'' (Herbst) of Mona Island crustaceans |journal=[[Crustaceana]] |volume=76 |pages=547–558 |doi=10.1163/156854003322316191}}
*{{cite journal | quotes=no|author=Greenaway, P. |year=2003 |title=Terrestrial adaptations in the Anomura (''Crustacea'': ''Decapoda''). In: Lemaitre, R., and Tudge, C.C. (eds) "Biology of the Anomura". Proceedings of a symposium at the Fifth International Crustacean Congress, Melbourne, Australia, 9-13 July 2001 |journal=Memoirs of Museum Victoria |volume=60 |issue=1 |pages=13–26}}
* [http://www.vifishandwildlife.com/Fisheries/MasterPlan/FinalPlan/Sections/Appendix1b.pdf#search=%22%22hermit%20crab%22%20%22Cittarium%20pica%22%22 Marine resources and fisheries strategic and comprehensive conservation plan – 2005, Appendix 1B: marine species overview, invertebrate species]
[[Category:Anomura]]
[[Category:Fauna of the Caribbean|Hermit crab, Caribbean]]
[[Category:Terrestrial crustaceans]]
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