hermit crab

Crabs of the family paguridae and coenobitidae. Most crabs have a hard shell covering their whole body and four sets of walking legs. Hermit crabs have only three pairs of walking legs, and lack the hard covering on the rear portion of their body, and so use empty shells to protect themselves (although in some areas, hermit crabs don't use shells at all. Rather they will live in plant stems, sections of bamboo, broken coconut shells, hollow pieces of wood, coral or sponge).

Hermit crabs occur all over the world, and live in water, on land (like the variety often kept as a pet), or sometimes even in trees.

The hermit crab has four pairs of legs, the front-most of which form claws. The claws they serve not only to aid in scavenging (hermit crabs are scanvengers and eat almost anything), but also to block the entrance to their shell. The right claw is usually larger and the body of the crab usually curls to the right (to fit the curvature of the shell). The rear-most pair of legs is used by the crab to grip the central column of the shell. Only the middle two pairs of legs are used for walking.

When a hermit crab outgrows a shell, it will leave its home in search of a new one, often removing the current occupant with its claws. Many animals may live upon the shell (such as sponges or sea anemones), feeding on what the hermit crab spreads about. When the hermit crab finds a new home, it is common for the animals on the old shell to move onto the new one, or for the crab to actually transplant the creatures himself. these animals serve as camouflage.

In the wild, hermit crabs are usually found in groups of about 25. If kept as pets, they do best in groups. In the wild, hermit crabs can live up to 25 years and attain huge sizes, but in captivity they will usually live less than a year, though with good care they may live to four years old.

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references: www.britanica.com, http://www.xs4all.nl/~pal/hermit.htm, http://www.york.biosis.org/zrdocs/zoolinfo/grp_crus.htm, http://www.mov.vic.gov.au/crust/hermgall.html

Land hermit crabs are popular creatures found in most pet stores. It is their small size and general easy care that make them so popular for smaller children. There are two main species that can be found within the US: Coenobita clypeatus, also known as the Purple Pincher, and Coenobita compressus who’s common name is the Ecuadorian Crab.

Purple Pincher
Just as the name implies the large claw on these crabs is generally purple and sometimes has a lighter tip. Another characteristic of the Purple Pincher is a larger number of setae on it’s exoskeleton. When you look at the legs of the crab you will see lots of dots, they are the hair-like filaments known as setae. The eyes of these crabs are rounded and sometimes have a flattened lower portion to the eye. Their heads are usually brown/tannish with darker purple/brown legs. Smaller crabs tend to have a light head with a dark spot in the center.

Found inland away from the seashore, these crabs usually live off of whatever falls to the forest floor.

Ecuadorian Crab
Unlike their counter-parts, these crabs have far less setae on their exoskeletons, only small areas on the front edges of both claws. The eyes of the Ecuadorian are elongated, and they usually have stripes on the sides of their head. Unlike the Purple Pincher who has lighter tips on its legs, this crab has darker reddish tips on lighter orange/tannish legs.

Native to Ecuador, these crabs live near the seashore around tidal pools and high-tide-zones. In order to live in captivity it is essential that seawater be provided for them. Synthetic sea salt can be found in pet stores to compensate for not living near the ocean.

Crab Care
You can have both species in the same habitat without worry. Just provide a dish of saline water and a dish of fresh water and both will cohabitate nicely. It is important that you never keep a single crab, always at least two. Despite the misleading name, hermit crabs are not hermits. They are very social and will become depressed and sometimes die if left alone for too long.

If you have a crab and notice it isn’t active, try purchasing another crab. Usually in a matter of days you will see a marked increase in activity, including more chirping noises at night as they talk to each other. Another reason for inactive crabs is the temperature in the habitat is too low. Try purchasing a heat lamp, it doesn’t need to be any higher than say a 75 watt bulb. It is important that the temperature not dip below 70 F as the crabs will slow down, stop eating and usually die.

Note: Never put large crabs in with small crabs. The larger crabs will usually kill the smaller crabs as they are more aggressive and more powerful overall.

I've had hermit crabs since 1999, and my knowledge came from a book I read way back then that I no longer own, so I can't tell you the name as a reference, only that it was a Hermit Crab pet care book.