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Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > Brachyurans > Family Pilumnidae
Common hairy crabs
Pilumnus vespertilio
Family Pilumnidae
updated Sep 2019

if you learn only 3 things about them ...
'Hair' covers almost every part of the body!
The hairs trap sediments, adding to their camouflage. So please watch out when you step among the rocks.
They are mildy poisonous!

Where seen? Hairy crabs are commonly seen on rocky and coral rubble areas on many of our shores. The "teddy-bear" of crabs, these hairy little creatures fluff up in the water and look positively cuddlesome. But they are hard to spot and usually well hidden, especially during the day. They are more active at night, but even then, they usually scuttle into the nearest crack or crevice at the first sign of danger.

These little crabs are not the same as the large 'Hairy crabs' that are served in our restaurants as seafood.

Features: Body width 3-5cm. As its name suggests, its body and limbs are covered with long, silky hairs. These trap sediments allowing the crab to blend perfectly with its surroundings. In the water, its hairs 'fluff up' breaking up its body outline. It also moves slowly and thus overlooked as some bit of drifting rubbish. It has large claws, with black or light brown tips. It has reddish eyes.

The Common hairy crab (Pilumnus vespertilio) is the most commonly encountered hairy crab on our shores and reefs. It has long, soft hairs and has been described as having the appearance of a mop. The various species of hairy crabs are very difficult to distinguish in the field.

Labrador, Jun 08

Sentosa, Aug 04

A pair mating?
Cyrene Reef, Jun 08
Photo shared by Toh Chay Hoon on flickr..
What does it eat? The Common hairy crab eats mainly seaweed. It may also eat toxic zoanthids (colonial anemones) and this makes the crab mildly poisonous. Various hairy crabs on our shores have been observed nibbling on hard seaweeds, sponges and even appearing to snack on bristleworms, possibly having a taste of a nudibranch and carrying a clam into a burrow.

Status and threats: Several of our hairy crabs are listed among the threatened animals of Singapore.
Like other creatures of the intertidal zone, they are affected by human activities such as reclamation and pollution. Trampling by careless visitors also have an impact on local populations.

Eating a bristleworm!
Pulau Semakau, Mar 08

Eating a bristleworm.
Cyrene Reef, Oct 08
Shared by Toh Chay Hoon on her flickr.

Eating a bristleworm.
Cyrene Reef, Oct 08
Shared by Shawne Goh on facebook.

Nibbling on a Hairy olive sponge.
Terumbu Pempang Tengah, Apr 12

Nibbling on hard seaweed.
Labrador, Feb 06

About to nibble on nudibranch?
Pulau Hantu, Jul 08

About to nibble on a sponge?
Terumbu Pempang Tengah, May 21
Shared by Vincent Choo on facebook.
Common hairy crab dragging a seahare into its burrow.
Terumbu Bemban, Apr 22. Video shared by Juria Toramae

Common hairy crabs on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

East Coast Park (B), Jun 21
Photo shared by Vincent Choo on facebook.

Berlayar Creek, Oct 17
Photo shared by Chris Wong on facebook.

Sentosa Serapong, Dec 20
Photo shared by Vincent Choo on facebook.

Small Sisters Island, Aug 20
Photo shared by Toh Chay Hoon on facebook.

Terumbu Hantu, Jul 20
Photo shared by Dayna Cheah on facebook.

Pulau Semakau East, Jan 16
Photo shared by Jonathan Tan on facebook.

Beting Bemban Besar, May 11
Photo shared by Loh Kok Sheng on his blog.

Terumbu Raya, Mar 09
Photo shared by Loh Kok Sheng on flickr.

Terumbu Bemban, Jun 20
Photo shared by Dayna Cheah on facebook.

Pulau Biola, Jan 22
Photo shared by Vincent Choo on facebook.

Pulau Biola, Dec 09

Terumbu Berkas, Jan 10

Pulau Berkas, Feb 22
Photo shared by Vincent Choo on facebook.

Terumbu Salu, Jan 10
Photo shared by Loh Kok Sheng on his flickr.

Pulau Pawai, Dec 09

Pulau Sudong, Dec 09

Pulau Salu, Apr 21
Photo shared by Toh Chay Hoon on facebook.

Common hairy crab (Pilumnus vespertilio)

Hairy crabs about to mate?
Common hairy crab (Pilumnus vespertilio) mating

Links References
  • 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.
  • Chou, L. M., 1998. A Guide to the Coral Reef Life of Singapore. Singapore Science Centre. 128 pages.
  • 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.
  • Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened plants and animals of Singapore. Nature Society (Singapore). 285 pp.
  • Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore. National Council on the Environment. 163pp.
  • Jones Diana S. and Gary J. Morgan, 2002. A Field Guide to Crustaceans of Australian Waters. Reed New Holland. 224 pp.
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