Hermit crab
Coenobita compressus
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Subphylum: Mandibula Class: Crustacea Order: Decapoda Suborder: Pleocyemata Infraorder: Anomura Superfamily: Paguroidea Latreille, 1802
Families
Coenobitidae Diogenidae Lithodidae Paguridae Prapaguridae Pylochelidae Pylojacquesidae

Hermit crabs are decapod crustaceans of the superfamily Paguroidea ^[1]. Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " The mandible (from Latin mandibula, "jawbone" or inferior maxillary bone forms the lower Jaw and holds the lower teeth in place Structure of crustaceans As Arthropods crustaceans have a stiff Exoskeleton, which must be shed to allow the animal to grow ( Ecdysis or molting The decapods or Decapoda ( literally means "ten footed") are an order of Crustaceans within the class Malacostraca, including many Pleocyemata is a sub-order of decapod crustaceans, erected by Martin Burkenroad in 1963  Anomura (sometimes Anomala) is a group of decapod Crustaceans including Hermit crabs and others Pierre André Latreille ( November 20, 1762 - February 6, 1833) was a French entomologist. In Biological classification, family ( Latin Coenobitidae are a family of Hermit crabs with only two genera * Birgus, the Coconut crab, and * Coenobita, Diogenidae is a family of Hermit crabs sometimes known as "left-handed hermit crabs" because in contrast to most other hermit crabs it is the left King crabs, also called stone crabs, are a family of Crab -like decapod Crustaceans chiefly found in cold seas Paguridae is a family of Hermit crabs of the order Decapoda. It contains the following genera  Agaricochirus The decapods or Decapoda ( literally means "ten footed") are an order of Crustaceans within the class Malacostraca, including many Structure of crustaceans As Arthropods crustaceans have a stiff Exoskeleton, which must be shed to allow the animal to grow ( Ecdysis or molting They are not closely related to true crabs. Crabs are decapod Crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (βραχύ / brachy

Most species of hermit crabs have long soft abdomens which are protected from predators by the adaptation of carrying around a salvaged empty seashell, into which the whole crab's body can retract. In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. A seashell, also known as a sea shell, is the Common name for a hard protective outer layer a shell or in some cases a " test " that was created Most frequently hermit crabs utilize the shells of sea snails, marine gastropod mollusks. The word snail is a Common name that can be used for almost all members of the Molluscan class Gastropoda which have coiled shells in the Marine is an Umbrella term. As an adjective it is usually applicable to things relating to the Sea or Ocean, such as Marine biology, Marine The class Gastropoda or the gastropods, also previously known as gasteropods, or univalves, and more commonly known as Snails Molluscs are animals belonging to the phylum Mollusca. There are around 250000 extant Species within the phylum with an estimated 70000 The tip of the hermit crab's abdomen is adapted to clasp strongly onto the columella of the snail shell. The columella (meaning little column is an anatomical feature of a coiled Snail shell or Gastropod shell. As the hermit crab grows in size it has to find a larger shell and abandon the previous one.

This habit of living in a second hand shell is what gave rise to the popular name "hermit crab", which is a reference to the idea of a hermit living alone in a small cave.

There are about five hundred known species of hermit crabs in the world, most of which are aquatic and live in saltwater at depths ranging from shallow coral reefs and shorelines to deep sea bottoms. An aquatic animal is an Animal which lives in water for most or all of the time However in the tropics, a number of species are terrestrial, and some of these are quite large, for example, Coenobita clypeatus. Terrestrial animals are Animals that live predominantly or entirely on land as compared with Aquatic animals which live predominantly or entirely in the water (e The Caribbean hermit crab ( Coenobita clypeatus) also known as the tree crab, the tree-climbing crab, the Soldier crab

A number of other species, most notably king crabs, have abandoned seashells for a free-living life; these species have forms which are more similar to true crabs, and are known as carcinised hermit crabs. King crabs, also called stone crabs, are a family of Crab -like decapod Crustaceans chiefly found in cold seas Carcinisation (or carcinization) is a hypothesised process whereby a Crustacean evolves into a Crab -like form from a non-crab-like form

Hermit crabs live in the wild in colonies of 100 or more, and do not thrive in smaller numbers.

Shell competition

Hermit Crabs picking at the underside of a dead Gumboot chiton, Cryptochiton stelleri in a California tide pool

As hermit crabs grow they require larger shells. The gumboot chiton, Cryptochiton stelleri, also known as the giant pacific chiton, is the largest of the Chitons growing to 33  cm (13 in Tide pools (also tidal pools, rock pools or rock and roll pools) are rocky pools by Oceans that are filled with Seawater. Since intact gastropod shells are a limited resource, there is frequently strong competition among hermit crabs for the best available shells. The class Gastropoda or the gastropods, also previously known as gasteropods, or univalves, and more commonly known as Snails The availability of empty snail shells at any given place depends primarily on the relative abundance of gastropods in the right range of sizes, compared to the demographics of the population of hermit crabs.

An equally important issue is the frequency of organisms which prey upon gastropods but leave the shells intact ^[2]. A hermit crab with a shell that is too small cannot grow as fast as hermit crabs with well fitting shells, and is more likely to be eaten ^[3].

For some larger marine hermit crab species, having one or more sea anemones growing on the shell can be very useful, because the anemones tend to scare away fish and other marine predators that might otherwise attack the crab. Marine is an Umbrella term. As an adjective it is usually applicable to things relating to the Sea or Ocean, such as Marine biology, Marine Sea anemones are a group of water dwelling predatory animals of the order Actiniaria; they are named after the Anemone, a terrestrial Flower The sea anemone also benefits because it is well positioned to consume loose fragments of the hermit crab's meals. Furthering this mutualism, sea anemones can transfer to a new shell when the hermit crab changes shells. Mutualism is a Biological interaction between individuals of two different Species, where both individuals derive a fitness benefit for example increased

Development

anemone hermit crab

The various types range in size from the Pacific hermit crab, which rarely grows larger than a peach, to Coenobita brevimanus which can approach the size of a coconut. Sea anemones are a group of water dwelling predatory animals of the order Actiniaria; they are named after the Anemone, a terrestrial Flower Coenobita brevimanus is a species of land Hermit crab native to the east coast of Africa and the south west Pacific Ocean. The shell-less hermit crab Birgus latro is the world's largest terrestrial invertebrate. The coconut crab ( Birgus latro) is the largest land-living Arthropod in the world Terrestrial hermit crabs begin their lives in the sea, but through a process of moulting develop the ability to breathe air. Ecdysis is the Molting of the Cuticula in Arthropods and related groups ( Ecdysozoa) After the last developmental moult, the young hermit crab will drown if left in water for an indefinite period of time. Their link with the sea is never entirely broken however, as hermit crabs carry a small amount of water in their shells at all times to keep their abdomen moist and their modified gills hydrated. It is believed that C. brevimanus is the species of Coenobita best adapted to life on water and land

Reproduction

The reproductive organs of hermit crabs are located near and just below the crab’s heart and open to the outside at the base of the last pair of walking legs in the male. The Genus Coenobita contains about thirteen Species of terrestrial Hermit crabs They are able to live on land because of their In the female, they’re located at the base of the middle pair of walking legs. Female hermit crabs usually lay their eggs shortly after copulating, however they can also store sperm for many months. The eggs are fertilized as they are laid by passing through the chamber holding the sperm. The eggs are carried and hatched in a mass attached to the abdomen inside the shell. The number of eggs is usually large, but depends on the crab’s size. The developing crabs go through four stages, two of which (the baupilus and protozoea) occur while still in the egg. Most crabs hatch at the third stage, the zoea. This is a larvae stage wherein the crab has several long spines, a long narrow abdomen, and large fringed antennae. The fourth stage of development is the magelops. Hermit crabs are usually born in the ocean, near the shore. Because of this, hermit crabs cannot reproduce in captivity. After the crabs are born, they move inland away from the water, where they search for abandoned shells to inhabit. Hermit crabs then begin growing and developing through a process called moulting. Ecdysis is the Molting of the Cuticula in Arthropods and related groups ( Ecdysozoa) In this process, the crabs shed their exoskeleton. During this, the crabs are extremely vulnerable and inactive, and usually find protection by burrowing in the ground. It takes around 10 days for their new exoskeleton to harden, and during this period the crab is able to regenerate any lost or broken claws or legs. A hermit crab can molt as often as every other month when young, or every 18 months when they are older. The life span of the hermit crab in the wild is up to 30 years, and 6 to 9 months as a pet.

Some notable species

• Birgus latro, coconut crab
• Ciliopagurus strigatus, Halloween hermit crab
• Clibanarius tricolor, Blue legged hermit crab
• Coenobita cavipes
• Coenobita clypeatus, Caribbean hermit crab
• Coenobita compressus, Ecuadorian hermit crab
• Coenobita perlatus, strawberry land hermit crab
• Coenobita variabilis
• Pagurus bernhardus

Hermit crabs as pets

There are several species of hermit crabs that are common in the marine aquarium trade. The coconut crab ( Birgus latro) is the largest land-living Arthropod in the world The halloween hermit crab ( Ciliopagurus strigatus) is a species of Hermit crab native to the Indo-West Pacific The Blue-Legged Hermit Crab, also known as the Tricolor Hermit, It feeds on green hair algae and Cyanobacteria. Coenobita cavipes is a species of land Hermit crab native to the eastern parts of Africa, the Philippines, China, Japan The Caribbean hermit crab ( Coenobita clypeatus) also known as the tree crab, the tree-climbing crab, the Soldier crab The Ecuadorian hermit crab ( Coenobita compressus) also known as the Pacific hermit crab is a species of land Hermit crab commonly sold in The strawberry land hermit crab ( Coenobita perlatus) is a Species of terrestrial Hermit crab. The Australian land hermit crab ( Coenobita variabilis) is one of two terrestrial Hermit crab species native to Australia and is found in northern parts Pagurus bernhardus is the common marine Hermit crab of Europe's Atlantic coasts A marine aquarium is an Aquarium that keeps marine plants and animals in a contained environment These omnivorous or herbivorous species are useful in the household aquarium as scavengers, eating algae and other debris. Omnivores (from Latin omne all everything vorare to devour are species that eat both Plants and Animals as their primary Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell Scavenging, or necrophagy, is a Carnivorous Feeding behaviour in which a predator consumes Corpses or Carrion that were killed Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms Debris (ˈdeɪbriː/ /dɛˈbriː is a word used to describe the remains of something that has been otherwise destroyed They also eat many fruits and vegetables.

Hermit crabs in an aquarium.

The scarlet hermit crab, or red reef hermit crab, Paguristes cadenati, is a handsome and interesting species with a bright red body and yellow eyestalks, and stays rather small (about 2–5 cm / 1–2 inches across). Paguristes cadenati (the scarlet hermit crab or red reef hermit crab) is a small (about 2–5  cm / 1–2  Inches across A centimetre ( American spelling: centimeter, symbol cm) is a unit of Length in the Metric system, equal to one hundredth Inches redirects here To see the Les Savy Fav album see Inches. Smaller species of a similar passive nature include the zebra hermit crab (brown legs with white bands), the red-tip crab and blue-legged crab. In Europe, the common hermit crab, Pagurus bernhardus, is popular. Pagurus bernhardus is the common marine Hermit crab of Europe's Atlantic coasts While most species available in pet stores are small like those listed above, and are simply scavengers, others may grow quite large (some on the Pacific coast can grow to 30 cm / 12 inches) and may eat coral, clams and other crustaceans. Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many Clam is a word which can be used for all some or only a few Species of Bivalve Mollusks the word is a Common name which has Most marine hermit crabs will appreciate a salinity of between 1. Salinity is the Saltiness or dissolved salt content of a body of Water. 023 and 1. 025 (measured in specific gravity), and temperatures between 4–14°C (temperate species) and 24–27°C (tropical species), with a good bed, algae to graze on and a variety of shells to change into. Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically The Celsius Temperature scale was previously known as the centigrade scale. They will happily switch shells frequently if given the opportunity - an interesting display to watch. There are approximately 15 terrestrial species in the world, and, of those, the following are commonly kept as pets: Caribbean hermit crab, Coenobita clypeatus, and the Ecuadorian hermit crab, Coenobita compressus. The Genus Coenobita contains about thirteen Species of terrestrial Hermit crabs They are able to live on land because of their The Caribbean hermit crab ( Coenobita clypeatus) also known as the tree crab, the tree-climbing crab, the Soldier crab The Ecuadorian hermit crab ( Coenobita compressus) also known as the Pacific hermit crab is a species of land Hermit crab commonly sold in Other species such as Coenobita brevamanus, Coenobita rugosus, Coenobita perlatus or Coenobita cavipes are less common but growing in availability and popularity as pets. In certain regions of the Caribbean, such as Jamaica, hermit crabs are commonly used in a sport known as crab racing, where they are placed in the center of a ring and whichever crab reaches the outside of the ring first wins. The Caribbean (ˌkærəˡbiən kæ'rəbiən Cariben|Caraïben or Caraïben; Caraïbe or more commonly Antilles; Caribe is a Region consisting Jamaica (ˈdʒəˈmeɪkə} is an Island nation of the Greater Antilles, in length and as much as in width situated in the Caribbean Sea. Hermit crabs eat a variety of food, and can live as long as 30 years. They used to be thought of as a "throwaway pet" that would only live a few months. With proper care, including mimicking the environment they originated from and proper feeding, they can thrive for many, many years.

References

External links

• Ecuadorian Hermit Crabs Wiki