learn only 3 things about them ...
group includes crabs usually found on sandy shores: fiddler
crabs, soldier crabs, sand bubblers and ghost crabs.
They come out at low tide and cover the shore. Don't step
They are very shy. To see them, wait quietly without moving.
seen? Crabs belonging to this family include some of the
most commonly encountered on our shores during the day: fiddler
crabs (Uca sp.), sand bubbler crabs (Scopimera and Dotilla spp.) and soldier crabs (Dotilla myctiroides). Others like the ghost
crabs (Ocypode sp.) are only active at night.
Features: Members of the family
Ocypodidae are distinguished by eyes on stalks, usually set close
together. Some have very long stalks indeed, relative to their body
size. These eye-stalks fold away into grooves on the body, so the
crab can scramble into hiding places without breaking the stalks.
Their bodies tend to be squarish, although some like sand bubbler
crabs and soldier crabs have almost spherical bodies. "Ocy"
means fast and "podi" foot in Greek. And indeed, most are
fleet footed indeed!
What do they eat? The smaller
members tend to feed on edible bits, sifting the sand or mud for them.
Larger ones such as ghost crabs are scavengers and forage on the shores
for the recently dead.
eye stalks of a ghost crab 'fold' away
into grooves at the side of its body.
Tanah Merah, Aug 09
Sentinel crab has super long eye stalks.
Pulau Hantu, May 05
Some fiddler crabs have brightly coloured eye stalks.
Chek Jawa, Mar 09
crabs on Singapore shores
Ocypodoidea recorded for Singapore
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
in red are those listed among the threatened
animals of Singapore from 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.
**from Ng, Peter K. L. & N. Sivasothi, 1999. A Guide to the Mangroves
of Singapore II (Animal Diversity)
***Tan, Leo W. H. & Ng, Peter K. L., 1988. A Guide to Seashore
****Lim, S., P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea:
The Life and Times of Labrador Beach.
+from The Biodiversity of Singapore, Lee Kong Chian Natural History Museum.
Camptandriidae (previously in Ocypodidae)
****Baruna minuta (Mouthface
***Ilyogynis sp. (Mud feeder crab)
Dotillidae (previously Ocypodidae)
Dotilla myctiroides (VU: Vulnerable) (Soldier crab)
Ilyoplax sp. semaphore crabs
*Ilyoplax delsmani (VU: Vulnerable) (White semaphore crab)
Ilyoplax obliqua (Tweedie's semaphore crab)
Scopimera sp. (Sand bubbler crabs)
*Shenius anomalum (Shen crab)
crab (Dotilla myctiroides), Fiddler
crabs (Uca spp.), Semaphore
crabs (Ilyoplax spp.), Sentinel
crabs (Macrophthalmus spp.), Shen
crab (Shenius anomalum) Ng,
Peter K. L. & N. Sivasothi, 1999. A
Guide to the Mangroves of Singapore II (Animal Diversity).
Singapore Science Centre. 168 pp.
Crab (Ocypoda sp.) and Fiddler
crabs (Uca spp.) Tan, Leo W. H. & Ng, Peter K. L.,
Guide to Seashore Life. The Singapore Science Centre,
Singapore. 160 pp.
Olympians by Petra H. Lenz on the University of Hawaii website:
listing of records of animal performance, and the Ghost crab ranks
among the top fastest terrestrial animals.
feeders on Life
on Australian Seashores by Keith Davey on the Marine Education
Society of Australia website: Fact sheet on deposit feeders including
- 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.
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
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.