Hermit Crab - Western Isles - Hebrides Crustaceans

Hermit Crab - Western Isles

Hermit Crabs - Western Isles

There are more than 100 different species of hermit crab found in marine habitats around the world. Although hermit crabs are seen in deeper waters, hermit crabs are more usually seen in coastal waters where there is more food and places to hide.

Hermit crabs use whatever shells are available that are the right size in order to protect themselves and as they grow in size, they search for another shell to use as their home.

One empty shell on a beach can trigger a rush and as one crab gets a larger shell for a "home" another smaller crab gets a new home

Hermit Crabs are Omniverous Eating Small Fish - Insects - Worms
Hermit crabs are omnivorous animals that eat pretty much anything they can find in the surrounding water. Small fish and invertebrates including worms, are the most common prey for the hermit crab along with plankton and other food particles in the water.

Size and Lifespan
Hermit crab species range in size and shape, from species with a carapace only a few millimetres long to Coenobita brevimanus, which can live 12–70 years and can approach the size of a coconut. The shell-less hermit crab Birgus latro (coconut crab) is the world's largest terrestrial invertebrate

After mating, the female hermit crab carries large numbers of eggs in a mass that is attached to her abdomen. The hermit crab larvae hatch into the open ocean in just a few weeks, where they quickly moult exposing the adult hermit crab body underneath.

In some hermit crabs, fertilisation occurs internally, while in others, fertilization is external and occurs at the moment of egg-laying. The developing eggs are attached to the abdominal swimmerets present only in the females. A female is able to carry several thousand eggs into the water. The newly hatched hermit crabs are known as larvae. These young crabs live as microscopic plankton for several weeks before settling on the bottom and searching for a shell to inhabit.

Fourth of Crustacean Species
Hermit crabs account for one-fourth of crustacean species and typically hang out at rocky or sandy areas in temperate or tropical oceans from the deep sea to intertidal zones.

Shell Held in Place by Grippers- Uropods
A hermit crab’s shell is held in place by little grippers called uropods. Tiny scales cover the uropods and legs to provide traction. In addition, the crabs abdominal muscles contract to press against the inner walls of the shell for further stabilization.

Gills for Breathing
Marine and land hermit crabs use gills for breathing. Land hermit crabs require very humid air (with at least 70% of humidity) to survive. Despite well-developed gills, land hermit crabs cannot breathe under the water.

Mate in the Ocean
All types of hermit crabs mate in the ocean.

These crabs often get into fights with other crabs of their own type even.They lose claws in these fights, and many (up to 5%) adult crabs on the shore have missing claws or smaller claws re growing.

It is listed among the 100 "world's worst invasive types of invasive species


Young hermit crabs moult every few months, while adults moult once every 18 months..

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