The Ecuadorian hermit crab (Coenobita compressus) also known as the Pacific hermit crab is a species of land hermit crab

Hermit crab

Hermit crabs are decapod crustaceans of the superfamily Paguroidea. Most of the 1100 species possess an asymmetrical abdomen which is concealed in an empty gastropod shell that is carried around by the hermit crab.-Description:...

. It is one of the two land hermit crabs commonly sold in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, including the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, as a pet, the other being the Caribbean hermit crab

Caribbean hermit crab

The Caribbean hermit crab, Coenobita clypeatus, also known as the soldier crab, the West Atlantic crab, the tree crab, and the purple pincher , is a species of land hermit crab native to the west Atlantic, Bahamas, Belize, southern Florida, Venezuela, the Virgin Islands, and the West Indies...

 (Coenobita clypeatus).

Features and identification

Coenobita compressus is a member of the phylum Arthropoda and the class Malacostraca

Malacostraca

Malacostraca is the largest of the six classes of crustaceans, containing over 25,000 extant species, divided among 16 orders. Its members display a greater diversity of body forms than any other class of animals, and include crabs, lobsters, shrimp, krill, woodlice, scuds , mantis shrimp and many...

. They can be up to 12mm in length and are thought to be one the smallest species of land hermit crabs. They have four walking legs, a small pincer, a large pincer, and antennae

Antenna (biology)

Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....

. Many people who keep these hermit crabs as pets notice that Ecuador

Ecuador

Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

ians can be relatively fast walkers, even faster than Caribbean hermit crabs, and that they are quite active. The eyes of Ecuadorians are more oval-shaped when compared to the round eyes of Caribbean hermit crabs and are thicker. Their big claw has 4 or 5 small ridges on the upper part. The tips of the second pair of walking legs are darker than the rest of the leg. The abdomen of the Ecuadorian hermit crab is short and fat.

Ecuadorian hermit crabs vary greatly in color, some are bright (yellow

Yellow

Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–590 nm is yellow, as is light with a suitable mixture of red and green...

, dark grey

Grey

Grey or gray is an achromatic or neutral color.Complementary colors are defined to mix to grey, either additively or subtractively, and many color models place complements opposite each other in a color wheel. To produce grey in RGB displays, the R, G, and B primary light sources are combined in...

, or orange), but more often they are a tan color

Tan (color)

Tan is a pale whiteish, tawny shade of white. The name is derived from tannum used in the tanning of leather.The first recorded use of tan as a shade name in English was in the year 1590....

. Sometimes they may have a blue or green tint to their bodies or the insides of their legs. They also have comma-shaped eyes, unlike the "purple pincher" (Coenobita clypeatus), which has dot shaped eyes.

When choosing a shell, they tend to give preference to shells with a wide and round aperture

Aperture (mollusc)

The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....

. As with all hermit crabs, painted shells are harmful to them, as they often eat the paint chips and can be poisoned with chemicals used in the paint. This significantly shortens their life span.

Habitats

Native to Ecuador

Ecuador

Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

 and Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

, these hermit crabs live on the Pacific

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 seashore around tidal pools and high-tide zone. Their bodies have adapted to this seashore existence and in captivity, they require access to seawater as they must metabolize the salt

Salt

In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

 in it and bathe in it to maintain gill moisture. Failure to provide access to seawater (real or artificial) will result in death.

Like most hermit crabs they are scavenger

Scavenger

Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...

s and will consume seaweed

Seaweed

Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...

, dead fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 and other detritus

Detritus

Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...

 that washes up on the shore.

Studies

Coenobita compressus prefers the odors of foods that they have not recently eaten. The hermit crabs that were exposed to one food for at least 9 hours preferred foods having other odors for the next 6 hours. It is this short-term avoidance of food (like human beings who get bored with the same meals over and over again) that compels the crabs to seek out a wider range of food. This might be advantageous to the hermit crab, possibly through the consumption of a more nutritionally-balanced diet.

As pets

Hermit crabs overall were once seen as a "throwaway pet" that would live only a few months, but species such as Coenobita clypeatus has a 23 year lifespan if properly treated  and some have lived longer than 32 years. Similarly Ecuadorian hermit crabs have been known to live to over 30 years. In general, and despite their moniker, hermit crabs are social animals that do best in groups. They also require a temperature and humidity-controlled environment (ideally 70%-78%), and adequate substrate to allow them to bury themselves while molting.

External links

• Ecuadorian Hermit Crabs Wiki