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Moon snail Family Naticidae

Moon snails are not often seen during the day. They are usually more active at night, and remain buried in the sand during the day. They usually move just under the sand surface.

Amazing full moon: When a Moon snail is fully extended out of its shell, it has an amazingly large body compared to its shell. It achieves this by inflating its tissues with seawater. The body forms a wedge shape that helps the snail move under the sand. The front of the foot is used like a plough. A part of the foot covers the head as a protective shield. The tentacles and siphon stick out of this shield. The mantle (a part of its body) extends in two flaps over the shell on either side. A Moon snail's shell often remains shiny and lustrous because the mantle envelopes its shell, and the snail spends most of its time under the sand. Encrusting animals have little chance of establishing on the shell of a living Moon snail.

Moon food: Moon snails are fierce predators. They feed on bivalves and snails. A Moon snail wraps its huge body around the hapless prey to suffocate it. If this fails, it has a gland at the tip of its proboscis that secretes an acid to soften the victim's shell. With some help from its radula, a hole is created. The hole is usually neat and bevelled.

Moon babies: The sand collar is the Moon snail's egg mass. A moon snail lays her eggs at night, combining these with mucus and sand in a gelatinous sheet which hardens. She lies at the center of the collar as she creates it. Although the collar feels hard, plasticky and appears dead, each collar can contain thousands of living eggs. When the eggs hatch, the collar disintegrates. Thus, an intact collar has living snails in it! Please don't damage the sand collars. Sand collars are sometimes numerous on the sand bar and seagrass lagoon.

Role in the ecosystem: When a Moon snail dies, its shell is quickly taken over by a hermit crab. Many of the Moon snail shells you see on the surface will probably be so occupied. Living Moon snails are rarely seen above ground.

Human uses: Some larger Moon snail species are sold as food in Asian markets.

Some Moon snails
are patterned

Hole made
by a Moon snail?

Sand collar
of a Moon snail

Lined moon snail
Natica lineata

Another kind
of moon snail
Polinices sp.

quick facts
Shell around 2cm, sometimes seen

Classification:
Class Gastropoda
Phylum Mollusca

See also ...
Molluscs in general
Gastropods in general

Links
Moon snails on the Sea Slug Forum by Dr Bill Rudman: brief fact sheet with lovely photo of a colourful moon snail.
Naticidae on The Gladys Archerd Shell Collection at Washington State University Tri-Cities Natural History Museum website: brief fact sheet on moon snails with photos.
The Moonsnail Project by Dr Thor Hansen and Dr Patricia Kelley: a national project involving students to study the moonsnail with facts and photos of moonsnails.
Moon snails on the Lane Community College website: short fact sheet on moon snails, photos of sand collars including one with snails about to hatch.
Family Naticidae (Sand or Moon Snails) by D. L. Beechey on the The Seashells of New South Wales website: An introduction with photos of New South Wales species.

Other references

Fiene-Severns, Pauline, Mike Severns and Ruth Dyerly, 2000. Periplus Nature Guides: Tropical Seashells. Periplus Editions. 64pp.
Tan, K. S. & L. M. Chou, 2000. A Guide to the Common Seashells of Singapore. Singapore Science Centre. 160 pp.
Woodward, Fred, 1993. Identifying Shells. The Apple Press, London. 80 pp.
Harasewych, M.G., 1991 edition. Shells: Jewels from the Sea. Courage Books, USA. 224 pp.
Tan, Leo W. H. & Ng, Peter K. L., 1988. A Guide to Seashore Life. The Singapore Science Centre, Singapore. 160 pp. online version
Morten, Brian & John Morten, 1983. The Sea Shore Ecology of Hong Kong. Hong Kong University Press. 350 pp.

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