Introduction

Until studies confirmed and incurred new insight, it was generally believed that hermit crabs were crabs that inhabited gastropod shells for the purpose of shelter and defense from predators. As the crab expanded its dimensions, it disposed of its now incommodious shell. This shell was exchanged for a more voluminous one. This process repeats indefinitely until the crab terminates its growth or dies. When further analyzed, this system does not generate a sufficient level of protection during the transition between shells. During this component of the transition between shells, the crab was completely vulnerable and susceptible to consumption by predators.

It appears that specific species of hermit crabs have developed a solution for this predicament. As was revealed by observational studies with various species, hermit crabs are actually capable of inhabiting the crevices within a sponge. As the sponge grows, it conforms to gastropod shells to which it is adhered. Gradually, the crab will abandon the shell and inhabit a section of the porifera.

Such a relationship provides benefits for both parties that share in this aquatic symbiosis. Nourishment is attracted to the sponge. The crab is protected more efficiently from predators. It is still debated whether such relations are short term or long term.

How is such a system possible? The porifera does not actually develop on the body of the hermit crab itself. Instead, it is manifested upon a gastropod shell, which serves as its substrate. A gastropod shell commonly involved in this phenomena is that of snails. The gastropod may be alive, or its shell may be devoid of any living form. In living specimens, the gastropod may be engulfed by the sponge. Only its "foot" emerges to enable mobility. When the gastropod dies, and its remains decompose, the sponge will continue to prosper. At some point in time, if the sponge is not too maximal in size, the shell may be selected by a hermit crab. In time, the crab will no longer occupy the chamber of the shell but a chamber within the flagellated, expanding walls of the sponge. This domicile is probably more flexible than that of a shell. Eventually, the sponge may be disposed of for a more suitable home, but additional research will investigate this theory.

Hermit crab sponges and hermit crabs coexist in many ocean habitats throughout the world including Korea, Scotland, Chile, the Pacific Ocean, and the Mediterranean Sea. By far, the area in which hermit crab sponges are most populous and most frequently observed is Dog Island, Florida. Dog Island is an island in the northeastern region of the Gulf of Mexico, and it is also adjoined by St. George Sound. It is approximately six kilometers from the mainland. Studies conducted in January have been found to be the most successful in terms of substantiated research.

Often, hermit crab sponges are also identified as "mobile" or "portable" sponges. Despite their terminology, it is certain that hermit crab sponges are a very interesting example of the capabilities of sponges- the so-called "simplest" form of animal life.