Crabs, shrimp, woodlice

Crab and crustacean identifier

A rock turned over at low tide is the best hunting ground there is.

Crustaceans live where nobody thinks to look: under a stone, in a rockpool, beneath a flowerpot. This is the group of beach days and damp gardens — and one of the fastest to complete once you know where to look.

25 species4 min read
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In brief

How do you identify a crab or a woodlouse?

Crustaceans hide: under a stone, in a rockpool, beneath a flowerpot. That is what makes them easy to photograph once found — lifting the cover is enough, and the animal stays still for a few seconds before bolting. Image identification leans on carapace shape, claw pattern and leg proportion. The shore crab and the garden woodlouse are the two most common entries in this group, and the fastest way to start a collection. SafaRoll covers 25 crustaceans in the catalogue. One rule holds for the whole group: turn the stone, photograph, put it back exactly as it was.

When to use it
  • 01.

    At low tide, under a turned-over rock.

  • 02.

    Under a flowerpot, on a woodlouse.

  • 03.

    In a rockpool, on a shrimp.

25 species · crustaceans

European Green Crab

Carcinus maenas

Common

Red Swamp Crayfish

Procambarus clarkii

Common

Atlantic Ghost Crab

Ocypode quadrata

Common

Atlantic Blue Crab

Callinectes sapidus

Common

Gooseneck Barnacle

Pollicipes polymerus

Common

Red Rock Crab

Cancer productus

Common

Yellow Shore Crab

Hemigrapsus oregonensis

Common

Dungeness Crab

Metacarcinus magister

Common

Marbled Crab

Pachygrapsus marmoratus

Common

Signal Crayfish

Pacifastacus leniusculus

Common

Blue Land Crab

Cardisoma guanhumi

Common

Edible Crab

Cancer pagurus

Common

Common Hermit Crab

Pagurus bernhardus

Common

Peacock Mantis Shrimp

Odontodactylus scyllarus

Common

Triangle

Heterogenea asella

Common

Norway lobster

Nephrops norvegicus

Common

European Spider Crab

Maja squinado

Common

Virile Crayfish

Faxonius virilis

Uncommon

Thin-shelled Rock Crab

Grapsus tenuicrustatus

Uncommon

California Spiny Lobster

Panulirus interruptus

Uncommon

Warty Crab

Eriphia verrucosa

Uncommon

Caribbean Spiny Lobster

Panulirus argus

Uncommon

American Lobster

Homarus americanus

Uncommon

Red King Crab

Paralithodes camtschaticus

Uncommon

Coconut Crab

Birgus latro

Legendary
Frequently asked

What people often ask

Under any flowerpot, in a damp log pile or beneath a garden stone: woodlice are terrestrial crustaceans, and the most accessible members of the whole group.

The SafaRoll app — iOS

Identify crustaceans from one photo.

SafaRoll names the species in a second and turns it into a collectible card. Free, unlimited identification, no ads.

Download on theApp Store

Free · iPhone · Unlimited identification