Channel Clinging Crab in Cozumel
Channel Clinging Crab (*Mithrax spinosissimus*) in Cozumel: how to identify the reef's largest crab and when it is visible.
The largest crab on the reef: a heavy knobbled carapace, thick legs and blunt pale claws. Also called the king crab or spider crab locally.
Quick ID
| Scientific name | Mithrax spinosissimus |
|---|---|
| Group | Crustaceans — Lobster, Shrimp & Crabs |
| Typical size | 15–30 cm leg span |
| Depth range | 3–30 m |
| When to see it | Year-round |
| Active | Night |
| Conservation status | Least Concern |
| Notes | Best seen on night dives |
Where You Will See It In Cozumel
Deep in crevices and under ledges at Palancar Caves, Santa Rosa and Yucab, out in the open on night dives.
Reliable sites: Palancar Caves, Santa Rosa Wall, Yucab.
Behaviour
An algae grazer despite the size and the claws — it is not a predator. Wedges itself into a hole by day and comes out to feed after dark.
Commonly Confused With
- Arrow crab — Tiny body, spindly legs, striped rostrum.
- Spiny lobster — Lobsters have long antennae and a segmented tail rather than a broad carapace.
Diving Etiquette And Safety
Do not reach in. The claws are strong and the crab has nowhere to retreat inside a crevice.
Part of the Cozumel marine life guide · see Cozumel dive sites · plan your Cozumel dive trip
Photo: Nick Hobgood, CC BY-SA 3.0, via Wikimedia Commons.
