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Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > Brachyurans > Family Menippidae
Stone or Thunder crab
Myomenippe hardwickii
Family Menippidae
updated Dec 2019

if you learn only 3 things about them ...
Common but usually well hidden, look carefully for them.
They have big, powerful pincers. Don't touch them.
They are identified by their bright green eyes ringed in red.

Where seen?This sturdy crab is commonly seen on our Northern shores near freshwater sources, in rocky and rubbly area.

Features: Body width 10-12cm, smaller ones also often seen. Body oval, edge with four blunt points or 'teeth' which are not very obvious. Upper side drab grey or brown, underside dull orange. Large pincers smooth (no pimples) with black tips. One pincer is enlarged with a large molar-like tooth at the base of the finger. Walking legs sparsely hairy. It is identified by bright green eyes, often circled with red.

Pulau Sekudu, Jan 05

Pulau Sekudu, Jan 05

Green eyes ringed with red.
Steady crab: When a stone is overturned, other crabs usually madly dash out helter skelter. The stone crab merely tucks its limbs under its body and remains motionless. In this way, predators overlook it as they they are distracted by the more nervous crabs.

It is also called the Thunder crab because of the mistaken belief that if the crab pinches you, only a clap of thunder will make it let go. This is of course untrue. To make any crab let go of your finger (or any other body part), place its walking legs gently on the ground, somewhere near a hiding place. It will shortly let go and run into the hiding place. It is best, in the first place, not to handle crabs so that they don't pinch you at all.

A tiny juvenile.
Pasir Ris Park, Jul 08

Cyrene Reef, Mar 09
Shared by Loh Kok Sheng on his blog.

With eggs
Pulau Sekudu, Aug 05
What does it eat? The stone crab eats snails and clams, crushing their shells with its powerful pincers. Sightings also suggest that the crab may scavange on dead animals such as fishes and jellyfishes. One was also seen eating a seahare.

Sometimes mistaken for the Red egg crab (Atergatis integerrimus) and Maroon stone crab (Menippe rumphii).
Here's more on how to tell apart big crabs with big pincers seen on the rocky shores and coral rubble.

Eating a jellyfish
Beting Bronok, May 06

Eating something shredded.
Changi, Jun 08

Clinging onto a clam.
Pulau Sekudu, May 12

Stone crabs on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Working on the Mactra clam next to it?
Pasir Ris, Sep 20

Photo shared by Jonathan Tan on facebook.

Pasir Ris-Loyang, Oct 20
Photo shared by Loh Kok Sheng on facebook.

Pulau Ubin OBS, Jan 16
Photo shared by Loh Kok Sheng on facebook.

About to eat a cowrie?
Beting Bronok, Jul 20

Photo shared by Loh Kok Sheng on facebook.

Changi Lost Coast, Jun 22
Photo shared by Loh Kok Sheng on facebook.

Berlayar Creek, Oct 15
Photo shared by Jonathan Tan on facebook.

Labrador, Nov 20
Photo shared by Vincent Choo on facebook.

Cyrene Reef, Feb 16
Photo shared by Juria Toramae on facebook.

Clutching a sea hare.
Chek Jawa, May 16
Photo shared by Jonathan Tan on facebook.

Terumbu Pempang Tengah, Nov 18
Photo shared by Richard Kuah on facebook.


  • Jonathan Tan Yong How. 30 Dec 2016. Thunder crabs Myomenippe hardwickii feeding on seahare and stingray. Singapore Biodiversity Records 2016: 177-178
  • Ng, Peter K. L. and Daniele Guinot and Peter J. F. Davie, 2008. Systema Brachyurorum: Part 1. An annotated checklist of extant Brachyuran crabs of the world. The Raffles Bulletin of Zoology. Supplement No. 17, 31 Jan 2008. 286 pp.
  • Lim, S., P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The Life and Times of Labrador Beach. Division of Biology, School of Science, Nanyang Technological University & Department of Zoology, the National University of Singapore. 160 pp.
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