Species group · Malacostracans

Hermit Crabs

WAnimals has 2 species of hermit crab, spread across 2 families (Diogenidae, Paguridae).

2 species

2 families

42 countries

52 parks

Ranges calculated from the entries that record the figure, not from all 2.

All 2 species of hermit crabs on WAnimals

Each one has its own full entry. This group does not replace them: it brings them together.

Hermit Crab

Pagurus bernhardus

Hermit Crab

Clibanarius erythropus

2 Not Evaluated

No species documented in this group is genuinely at risk according to the IUCN, with the data available today.

Recorded in 42 countries. The ones with the most species in the group:

It has to change shells several times as it grows, and now and then a group will queue up in order of size to swap shells one after another.
From Hermit Crab
The shell is its limiting resource, which is why hermit crabs compete intensely for them. An individual assesses an empty shell by inserting a claw, gauging the interior and the weight before deciding on the switch.
From Hermit Crab
And they form vacancy chains: when a large empty shell turns up, a queue of hermit crabs forms in order of size, and as soon as the largest moves in, each one takes the shell the one before has left. It is a well-documented collective behaviour, much cited in economics as an analogy for housing markets.
From Hermit Crab
When an empty shell turns up, several hermit crabs may line up by size and hand the shells on in a chain, each moving into the one the previous crab has left.
From Hermit Crab
It reappeared on the coasts of south-west England in 2016, after almost three decades without records, in a shift linked to the warming of the sea.
From Hermit Crab
It occupies empty gastropod shells, above all of Littorina striata, Mitra, Nassarius incrassatus and Stramonita haemastoma, and changes them as it grows.
From Hermit Crab