		wildsingapore homepage sitemap to the online guide search \| glossary seagrass lagoon index

seagrass lagoon

Sponge crab
Cryptodromia sp.
Family Dromiidae

Crab with a Live Cap: The Sponge crab uses its pincers to snip out a cap of sponge to fit over its body. To grip this cap as it walks around, the crab's last two pairs of legs are bent over its back and tipped with little pincers. If it cannot find a sponge, the crab will use an ascidian.

The sponge continues to live and grow and the crab constantly trims it to the right size. The sponge camouflages the crab so well that it is almost impossible to spot unless it moves. The distasteful nature of sponges may also discourage predators from investigating what is underneath.

Crab Food: The Sponge crab is a scavenger. Like other crabs that rely on a disguise, it tends to move slowly.

Sponge Crab
Cryptodromia sp.

Close-up showing
legs bent over
its back

quick facts
0.5-10cm, common in the seagrass lagoon

Classification:
Order Decapoda
Class Malacostraca
Subphylum Crustacea
Phylum Arthropoda

See also ...
Sponges and ascidians, the living animals that used by the Sponge crab!

Links
Sponge crabs on the Marine Crustaceans of Southern Australia page on the Victoria Museum website: brief info and photos of a crab with and without its sponge
Crab with a ton of sponge on Philip Slosberg's page: a photo of a crab with a huge sponge on its back.

Other references

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.
Tan, Leo W. H. & Ng, Peter K. L., 1988, A Guide to Seashore Life. The Singapore Science Centre, Singapore. 160 pp. online version

a companion website to the chek jawa guidebook website©ria tan 2003 www.wildsingapore.com

a companion website to the chek jawa guidebook
website©ria tan 2003 www.wildsingapore.com