Paguristes eremita
Look for this shell-dwelling hermit crab on rocky ledges in the French Riviera, Istria and the Slovenian coast in 14.5-20.5C water.
Small crab living inside a scavenged snail shell, with only the reddish-orange claws and eyestalks poking out to give it away. The claws are furry-looking with fine bristles, and one claw is noticeably larger than the other for blocking the shell entrance. Body colour is hard to judge since most of it stays hidden, so divers key on the shell shape moving in an oddly deliberate, jerky walk across rock or rubble.
Divers usually spot it shuffling slowly over rock, rubble or seagrass edges, using its shell as portable armour and retreating fully inside the moment a torch or hand gets close. It tends to keep to the same low, sheltered ground rather than climbing into the open water column, and sightings are generally single individuals rather than groups.
As it grows it has to abandon its current shell and go shell-shopping for a roomier one, a vulnerable few moments when it is briefly exposed with no armour at all.
No clear seasonal pattern shows up in the sightings, and with a comfort range of roughly 14.5 to 20.5C it can be found across the water temperatures typical of the Mediterranean for most of the year.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most reliably logged along the French Riviera and Provence coast, with further sightings around Corsica and Occitanie. Outside France it turns up on rocky sites in Istria (Croatia), along the Slovenian coast, and on Italy's Adriatic coast, though always as an uncommon to rare find rather than a guaranteed sighting.
Mapping where Hermit Crab is logged…
Best logged along France's Riviera and Provence coast, plus Corsica and Occitanie. It also shows up on rocky Adriatic sites in Istria (Croatia), along the Slovenian coast, and on Italy's Adriatic coast.
There's no strong seasonal pattern in the sightings, so it's treated as a year-round find. It sits comfortably in water from about 14.5 to 20.5C, a range common on the Mediterranean coast for most of the year.
Look for a snail shell moving with a jerky, deliberate walk across rock or rubble, with reddish-orange, slightly furry claws poking out the opening. One claw is larger than the other and gets used to plug the shell when threatened.
No, they're harmless and will simply withdraw into their shell if you get close. There's no sting, bite risk or aggressive behaviour to worry about.
It doesn't grow its own shell, it scavenges an empty snail shell and has to trade up to a bigger one as it grows, leaving it briefly unprotected during the swap.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Sally Lightfoot Crab
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