seen? This tiny pretty snail is found in the thousands,
lying just beneath the sand surface on some parts of our Northern
shores, on sand bars or sandy shores. In the past, however, they were
more common on many of our mainland shores. Elsewhere, they are abundant
on fine sandy bottoms.
0.8-1cm. Shell thin, circular, glossy with an amazing variety
of colours and patterns. It is said that no two button snails are
alike! These snails are so enchanting that the guides call them the
'Jewels of Chek Jawa'.
thin, made of a horn-like material with concentric rings, yellow.
The flexible operculum allows the animal to withdraw deep into the
coils of the shell.
Body pale speckled,
of the mantle fringed with long tentacles. Foot long,
leaf-like. Tiny eyes on long stalks, long tentacles finely banded,
with two tubular siphons, one with fringes.
The long mobile foot can be used to burrow rapidly into wet loose
fine sand (the snail doesn't do so well in compact dry sand). The
streamlined shell helps them burrow rapidly. To escape predators,
button snails make a short, spiralling leap then quickly bury themselves
into the sand again. Sometimes, on wet sand, you might see the tiny
trails left by panicky button snails, punctuated by little holes where
they disappeared into the sand.
When disturbed, submerged button snails may also pop up and float
on the water surface, sometimes forming 'rafts' of several snails.
After a while, the snails will sink one by one, and burrow into the
sand. Could this be a way for them to escape predatory snails and
other animals that can't swim? It may also allow them to disperse
to new places quickly?
What does it eat? More like bivalves
rather than snails, button snails lie just beneath the sand and filter
feed for detritus and plankton. Like bivalves, a button snail has
an inhalant siphon fringed with short tentacles which is used to suck
in water, and an exhalant siphon which expels the water. When there
isn't much food in the water, it may use its right tentacle and long
foot to gather edible bits on the sand surface.
Role in the ecosystem: Button
snails appear to be among the favourite prey of Moon
snails. Olive snails
have also been seen hunting them. Other large animals probably also
snack on them. Empty buttons shells are favourite homes of tiny hermit
crabs. So please resist the temptation of taking home even an
empty button snail. A homeless hermit crab might need it!
uses: Sadly, these beautiful tiny animals are collected,
killed and their shells sold as cheap curios and for handicrafts.
In the Philippines they are commonly gathered as food. Vendors traditionally
provide the buyer with an aromatic thorn from the Acacia to pry the
Status and threats: Button snails
were highly abundant in Singapore in the 1960's, but populations have
declined drastically as their habitats have since become degraded
or were lost. They are now listed as 'Vulnerable' on the Red List
of threatened animals of Singapore. Trampling by careless visitors
and overcollection can also have an impact on local populations.
A big pile of living Button snails
Chek Jawa, Feb 05
They can float, forming 'rafts'.
Changi, Jul 08
Closeup of shell opening and operculum.
Tanah Merah, Feb 07
Tanah Merah, Mar 10
East Coast Park, Aug 12
Tiny button snails leaping away
from a hunting moon snail.
East Coast, Jun 06
Cyrene Reef, Dec 10
Photo shared by Loh Kok Sheng on his
Hermit crab (left) and living Button snail (right)
Changi, Jun 05
Button snails leaping away from a Moon
Tanah Merah, Apr 05
snails on Singapore shores
- 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.
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.