Marine life  /  Hermit crabs  /  Giant hermit crab
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Species entry

Giant hermit crab

Petrochirus diogenes

The largest hermit crab in the region, usually in a queen conch shell, out on open sand at night.

Size
To 25 cm
Depth
1–25 m
Habitat
Sand and rubble, mostly at night
Active
Day and night
Range
Western Atlantic
Rarity
Florida
3 stars of 5, a good week should turn one up
SP-01
giant hermit crab · full body · habitat
4:3 · min 2400px

Twelve to twenty-five centimetres, the largest hermit crab in the Caribbean. The claws are covered in scale-like tubercles and the antennae are banded red and white, and it is big enough to occupy a full-grown queen conch shell.

The star-eye hermit crab has a blue star-burst pattern across the eye, which this one does not.

One to thirty metres on sand and rubble beside reef. The behaviour worth knowing is that it will attack and eat a living conch, taking both the meal and the shell. It is left-handed, so the larger claw is on the left.

Where to find:

LocationRarity Best monthsDepthHabitat
Florida United States editorial estimate
3 stars of 5, a good week should turn one up
Year-round
1–25 m
Sand and rubble, mostly at night
Bahamas Bahamas editorial estimate
3 stars of 5, a good week should turn one up
Year-round
1–25 m
Sand and rubble, mostly at night
Cayman Islands Cayman Islands editorial estimate
3 stars of 5, a good week should turn one up
Year-round
1–25 m
Sand and rubble, mostly at night

Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.

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