learn only 3 things about them ...
Cowries are often well camouflaged. Look carefully for
Their shells are highly prized, thus cowries are threatened
their shells covered, coowries are sometimes mistaken
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
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.
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.
on Singapore shores
Cypraeidae recorded for Singapore
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
arabica (Arabian cowrie) (VU:
Cypraea errones (Wandering
Cypraea gracilis (Graceful
Cypraea miliaris (Miliaris
Cypraea onyx (Onyx cowrie)
Cypraea ovum (Ovum cowrie)
Cypraea pyriformis (Pear-shaped
+Cypraea saulae (Saul's cowrie)
(Tiger cowrie) (EN: Endangered)
Cypraea vitellus (Milk-spotted
Cypraea walkeri (Walker's cowrie)
- 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.
- Abbott, R.
Tucker, 1991. Seashells
of South East Asia.
Graham Brash, Singapore. 145 pp.
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.
- Kuiter, Rudie
H and Helmut Debelius. 2009. World
Atlas of Marine Fauna
. IKAN-Unterwasserachiv. 723pp.