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Phylum Mollusca > Class Gastropoda
Cowries
Family Cypraeidae
updated Aug 13

if you learn only 3 things about them ...
Cowries are often well camouflaged. Look carefully for them.
Their shells are highly prized, thus cowries are threatened by over-collection.
With their shells covered, coowries are sometimes mistaken for slugs!

Cowries produce among the most beautiful and highly prized shells. One cowrie was even used as currency by Polynesians in the past; it is called the Money cowrie (Cypraea moneta)! However, a living cowrie is even more fascinating than an empty shell of a dead cowrie.

Where seen? Some species of cowries are still common on all our shores. Even these, however, are usually well camouflaged or well hidden. They are usually more active at night.

Two-in-one shell: A young cowrie's first shell is a narrow spiral. As it matures, it encloses this spiral shell with a larger outer shell which has the typical cowrie shape and slit-like opening with teeth. As the animal grows, the inner spiral layers may be reabsorbed to make room for the larger animal and the material reused to build a larger outer shell. A damaged shell appears to be a shell within a shell, but it is really one continuous shell. The shells of juveniles tend to be of one colour or banded. The full colours and patterns usually only appear in the shells of adults.

Marvellous mantle: When alive and moving around, the cowrie usually encloses its shell with its mantle (a part of its body). The mantle may have a different colour and pattern from the shell and is often also 'textured' with tiny projections. When the shell is covered by the mantle, a cowrie is sometimes mistaken for a slug. Here's more on how to tell apart slugs and animals that look like slugs.

The fleshy mantle is a highly specialised organ. It is the main architect of the glossy shell, as it lays down a layer of pearl-like substances as well as the colour and patterns. It also repairs and enlarges the shell and protects it from algae and encrusting animals. This is why a cowrie shell is so shiny and smooth. When disturbed, the entire mantle retracts into the shell.

What do they eat? As a group, cowries eat a wide variety of things from algae, sponges to scavenging and carnivorous cowries that eat other snails. Each has a radula adapted to its particular prey. Most cowries live in the intertidal zone, hiding during the day and emerging to feed at night. A cowrie has a pair of tentacles and a siphon, which is part of the mantle modified for breathing and sampling the water to look for food and mates.

Cowrie babies: The mother cowrie lays her eggs in a horny capsule attached to a hard surface by a short stalk, these capsules are grouped in a cluster. Some mother cowries remain with their egg capsules until they hatch. The eggs are at first white and turn dark grey as they mature. Some large cowries can live for 10 years, while smaller one for 2-3 years.

Human uses: Some cowries are popular in the live aquarium trade. Cowries are among the most harvested snails for the shell trade. In the past, they were traditionally collected for food. Some islanders use cowries to bait traps for octopus.

Status and threats: Recent estimates suggest that half the cowrie species in Singapore have been lost. The Gold-ringed cowrie (Cypraea annulus) has almost if not completely been wiped out on our shores. This small cowrie was previously found in large groups on our rocky shores and reef flats. It has a narrow yellow band around its greyish-white back. Although considered one of the most common cowries in our region, the Tiger Cowrie (Cypraea tigris) is now rarely seen. Both are listed as 'Endangered' while the Arabian cowrie (Cypraea arabica) is listed as 'Vulnerable' on the Red List of 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 and over-collection can also have an impact on local populations.


Eggs are white and turn dark grey
as they mature.
Chek Jawa, Oct 03


Another mama cowrie with her eggs.
Chek Jawa, Feb 05


The animal with tentacles and broad foot.
Labrador, Jun 05


When covered with the 'hairy'
mantle they are often mistaken for slugs
Pulau Sekudu, Jul 04


Cowries have a 'toothed' shell opening
Changi Point, Jul 02

A broken shell shows the internal
structure of a typical cowrie.

Cowries on Singapore shores




Family Cypraeidae recorded for Singapore
from Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore.
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 our observation
^from WORM

  Family Cypraeidae
  ^Annepona mariae=Cypraea mariae

^Arestorides argus=Cypraea argus

^Bistolida hirundo=Cypraea hirundo
^Bistolida kieneri=Cypraea kieneri
^Bistolida stolida=Cypraea stolida
^Bistolida ursellus=Cypraea ursellus

^Blasicrura interrupta=Cypraea interrupta

^Contradusta walkeri=Cypraea walkeri
(Walker's cowrie)

^Cribrarula cribraria=Cypraea cribraria

Cypraea tigris
(Tiger cowrie) (EN: Endangered)

^Eclogavena quadrimaculata=Cypraea quadrimaculata
(Four-spot cowrie)

^Erronea caurica=Cypraea caurica
^Erronea cylindrica=Cypraea cylindrica
^Erronea errones=Cypraea errones
(Wandering cowrie)
^Erronea onyx=Cypraea onyx
(Onyx cowrie)
^Erronea ovum=Cypraea ovum
(Ovum cowrie)
^Erronea pallida=Cypraea pallida
^Erronea pyriformis=Cypraea pyriformis
(Pear-shaped cowrie)
^Erronea rabaulensis=Cypraea rabaulensis

^Erosaria erosa=Cypraea erosa
^Erosaria gangranosa=Cypraea gangranosa
^Erosaria lamarckii=Cypraea lamarckii
^Erosaria miliaris=Cypraea miliaris
(Miliaris cowrie)
^Erosaria nebrites=Cypraea nebrites


^Ficadusta pulchella=Cypraea pulchella

^Leporicypraea mappa=Cypraea mappa

^Lyncina carneola=Cypraea carneola
^Lyncina lynx=Cypraea lynx
^Lyncina nivosa=Cypraea nivosa
^Lyncina ventriculus=Cypraea ventriculus
^Lyncina vitellus=Cypraea vitellus
(Milk-spotted cowrie)

^Mauritia arabica=Cypraea arabica (Arabian cowrie) (VU: Vulnerable)
^Mauritia eglantina=Cypraea eglantina
^Mauritia histrio=Cypraea histrio


^Melicerona felina=Cypraea felina

^Monetaria annulus=Cypraea annulus
(Gold-ringed cowrie) (EN:Endangered)
^Monetaria caputserpentis=Cypraea caputserpentis
^Monetaria moneta=Cypraea moneta


^Notadusta punctata=Cypraea punctata

^Nucleolaria nucleus=Cypraea nucleus

^Ovatipsa coloba=Cypraea coloba

^Palmadusta asellus=Cypraea asselus
^Palmadusta clandestina=Cypraea clandestina
^Palmadusta lutea=Cypraea lutea
+^Palmadusta saulae=Cypraea saulae
(Saul's cowrie)
^Palmadusta ziczac=Cypraea ziczac

^Purpuradusta fimbriata=Cypraea fimbriata
^Purpuradusta gracilis=Cypraea gracilis
(Graceful cowrie)
^Purpuradusta hammondae=Cypraea hammondae
^Purpuradusta minoridens=Cypraea minoridens

^Pustularia bistrinotata=Cypraea bistrinotata

^Staphylaea staphylaea=Cypraea staphylaea

^Talparia talpa=Cypraea talpa

^Zoila marginata=Cypraea margarita

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References

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