How Hermit Crabs Choose Their Shells

Hermit crabs are decapods crustaceans, of a Subphylum Crustacea and Superfamily Paguridae. Hermit crabs are detritovores which mean they feed on dead organic material especially plant detritus. Hermit crabs tend to use shells from other animals. The shell covers their soft abdomen and regulates moisture within it, which is very important for the gills. They have a segmented bodies and exoskeletons which is an external skeleton. Hermit crabs can live on land and sea. Most hermit crabs tend to be small.

Hermit crabs are very picky when it comes to choosing their shells. They tend to use borrowed shells, mainly from sea snail shell. A variety of mechanisms such as shell rapping, olfactory signals, and visual ques have been shown to transfer information about the quality of a shell. As a hermit crab grows they have to take into consideration that they will continuously grow and grow, so the shell that they do choose has to be a bit bigger than their actual size. If a crab chooses a shell that is too small or the same size as itself, the crab will eventually die or if it may be a female in this situation they would become infertile and may not be able to reproduce. Also if the shell is too big it can cause a strain on the hermit crab and cause the crab to eventually die. Hence it is very important that these hermit crabs choose the right shell to move into or else it can cost them their lives. A more dominant crab is able to initiate a shell switch with a subordinate crab who may give a higher quality shell.

Hermit crabs assess the shells also by colour, if the colour is too vibrate and conspicuous they may not consider it because it can be easy for predators to spot them. Tactical cues are also used to gather more accurate information on the shells. They can also use their antennae to detect chemical cues. The hermit crabs use their chelae and their walking legs to the assess the inside of the shell and also to make sure the aperture is of the right size. They can reject the shell at any point of examining it, if they think it is not of high quality or of their liking, only after making such decisions then they will decide to move into the new shell or not.

Cracked shells or shells with holes in them are not suitable for hermit crabs because the shell needs to be able to hold enough water to keep the gills moist. Hermit crabs are very social creatures and they tend to live in groups. Hermit crabs that live together, sometimes tend to help each other find shells. Four examples of crucial topics in animal behavior research, which are: mechanism, adaptive value, phylogen, and onotogeny. To conclude hermit crabs are very picky when it comes to choosing their shells, there are a lot of factors which affect which shell they may occupy or may not occupy.