learn only 3 things about them ...
Limpets are sometimes confused with barnacles.
Limpets can move! But only at high tide.
area around a limpet is often grazed bare of algae.
seen? Limpets are found many of our shores. Both on and
under stones, as well as on rocks and other hard surfaces. Sometimes
the shell is covered with algae and mud and the limpet might look
like a sea slug. Immobile at low tide, these abundant snails are often
considered uninteresting and ignored by visitors. But they are actually
quite amazing little creatures.
Features: 'Limpets' are molluscs
with an uncoiled, umbrella-shaped shell, often with ribs. They are
gastropods, and like the snails
more familiar to us, also have a broad foot upon which they creep
about. Unlike snails, however, limpets don't have an operculum to
seal the opening in their shell. Instead, they clamp down tightly
against the rock. Their grip is so strong that if you try to pry them
off, you will hurt them. So please don't do this. If you want to see
what the limpet looks like under its shell, have a look at the factsheets
Sometimes confused with barnacles
which are crustacea; small oysters
(Family Ostreidae) which are bivalves;
and slipper snails
(Family Calyptraeidae) which are another kind of gastropod. Unlike
limpets, all these other animals cannot move around. More on how to
tell apart shelled
animals found on rocks.
Limpets can move! Unlike the immobile
barnacles, limpets can move around. Like most other snails, limpets
have tentacles, a broad foot and a radula. The limpet's broad foot
firmly grips the rock to avoid being dislodged by waves or predators.
do they eat? Most limpets graze the thin layer of tiny
plants and animals that coat a rock. In fact, to find limpets, look
out for a 'bare' patch of rock! They feed at high tide. At
low tide, you may see some grazing at night or when it is cool or
wet. Those found in shallow tide pools may also continue to feed at
Home on the Rock: Some species of
limpets have a strong homing instinct and move back to the same resting
spot after a feeding bout.
This spot is often a slight depression in the rock which fits the
outline of the shell perfectly, and is called the 'home scar'. The
limpet creates this perfect spot by rubbing against the rock, wearing
away the shell and/or the rock so that a perfect fit is created! Even
as the limpet grows bigger.
Sometimes, you might come across a spot on a rock in the shape of
a limpet that is completely 'clean'. This could be the home scar of
a limpet that has recently come to an unhappy end. In the photo on
the right, you can see the feeding trails leading from the home scar.
Some limpets are believed to follow their mucus trails back to the
home scar. In some of these homing limpets, their mucus also stimulates
the growth of algae!
are limpets? Two major groups of snails have umbrella-shaped
shells. They come from quite separate groups and are not closely related.
One group of limpets called True limpets breathe through gills.
Some, like those of the Family Patellidae and Lottiidae do not have
holes in their shells.
The Family Fissurellidae includes the Keyhole
limpets which have a hole at the tip of their conical shells.
Water is sucked in from under the shell, passes over the two feathery
gills, and is then expelled out of the hole in the shell. To avoid
water loss through this hole, these limpets live in wetter places.
Another member of the Family Fissurellidae are the Shield-limpets
(Scutus sp.). Their bodies are a lot larger than their shell.
In fact, the shell might be completely covered by their mantle, making
them appear to be slugs. A Shield-limpet's
body usually folds up around the edges of the shell and may cover
most of the shell. They come in various colours. Their body may be
black or beige, and shell white or brown. These limpets are commonly
found under rocks on our shores.
Another group of limpets have lungs and breathe air. False limpets
(Family Siphonariidae) belong to this group and are closely related
to land snails and to Onch slugs (Family
Onchidiidae). They have a lung that can be filled with air or seawater.
Because they can breathe air, false limpets are often found higher
up on the rocks than limpets that breathe through gills. They lay
jelly-like egg masses on the rocks.
More on how to tell apart the various kinds
Limpet Babies: Siphonaria
limpets lay eggs in circular or coiling jelly-like masses that contain
thousands of eggs suspended in a gelatinous matrix, attached to a
hard surface. The free-swimming limpet larvae have a little spiral
shell like other 'normal' snails. As they develop, the shell flattens
and becomes umbrella-shaped.
Human uses: Large limpets are often harvested as food by
Status and threats: None of our
limpets are listed among the threatened animals of Singapore. However,
like other creatures of the intertidal zone, they are affected by
human activities such as reclamation and pollution. Over-collection
can also have an impact on local populations.
Limpets are commonly
seen on rocks.
Changi, May 02
Limpets in the middle of
a well-grazed portion of a boulder.
Chek Jawa, May 04
scar of recently demised limpet.
Tuas, Apr 05
False limpet, this Guam false limpet,
breathes through lungs.
Sisters Island, Nov 05
A True limpet, this Smooth limpet
Chek Jawa, Jan 05
mistaken for a slug,
the Hoof-shield limpet has a body
much bigger than its shell!
Chek Jawa, Jul 02
East Coast Park, Aug 11
East Coast Park, Aug 11
on Singapore shores
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.
+Other additions (Singapore Biodiversity Record, etc)
sp. (Smooth limpet)
Diodora reevei=^Diodora octagona
Scutus sp. (Hoof-shield
Scutus unguis (EN:
- Tan Siong Kiat, Lee Yen-ling & Rene Ong. 18 September 2015. A record of Singapore keyhole limpet, Diodora singaporensis. Singapore Biodiversity Records 2015: 131-132
- Tan Siong Kiat & Martyn E. Y. Low. 13 December 2013. New Singapore record of the slit limpet Montfortista oldhamiana. Singapore Biodiversity Records 2013: 106
- 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.
- Lim, S.,
P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The Life
and Times of Labrador Beach. Division of Biology, School of
Science, Nanyang Technological University & Department of Zoology,
the National University of Singapore. 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.
- Edward E.
Ruppert, Richard S. Fox, Robert D. Barnes. 2004.Invertebrate
Brooks/Cole of Thomson Learning Inc., 7th Edition. pp. 963
Jan A., 2005. Biology
of the Invertebrates.
5th edition. McGraw-Hill Book Co., Singapore. 578 pp.