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Phylum Mollusca > Class Gastropoda
Slipper snails
Family Calyptraeidae
updated Jul 2020
Where seen? These strange snails are almost always found on large shells inhabitated by hermit crabs. They are also seen on the undersides of large living horseshoe crabs.

What are slippers snails? Slipper snails are NOT bivalves (like oysters). They are gastropods that belong to the Family Crepidulidae.

Features: 2-3cm. Shell conical or flat domed. Several may be found stuck firmly onto inside of a shell occupied by a hermit crab. They take advantage of the constant current of freshly oxygenated water that the hermit crab creates for itself. They are also found on the underside of living horseshoe crabs.

Sometimes confused with limpets which are also gastropods but which can move about. Here's more on how to tell apart limpets, slipper snails and similar animals.

What do they eat? Slipper snails filter feed and possibly also gather the leftovers of the hermit crab's meals.

Slipper snail babies: Slipper snails can change gender. They are usually found in pairs. The larger one is the female and the smaller one male. When the smaller one grows big enough, it will change into a female! The females produce flask-shaped capsules with several eggs in one capsule. The capsules are brooded in the mantle cavity.

Two different kinds of slipper snails on this shell occupied by a hermit crab.
Changi, Apr 05

The smaller shell is usually the male.
Chek Jawa, Mar 05

Tanah Merah, Sep 13

On a horseshoe crab.
Changi, Jul 04

On a living scallop.
Changi, Aug 18

Some Slipper snails on Singapore shores

Family Calyptraeidae recorded for Singapore
from Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore.
^from WORMS

  Family Calyptraeidae
  ^Desmaulus extinctorium=Calyptraea extinctorium (Conical slipper snail)
^Siphopatella walshi=Crepidula walshi
(Flat slipper snail)



  • Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore (pdf), Raffles Museum of Biodiversity Research, National University of Singapore.
  • Tan, K. S. & L. M. Chou, 2000. A Guide to the Common Seashells of Singapore. Singapore Science Centre. 160 pp.
  • Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore. National Council on the Environment. 163pp.
  • Ng, P. K. L. & Y. C. Wee, 1994. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. The Nature Society (Singapore), Singapore. 343 pp.
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