CONTENTS
Flora index
Fauna index
guide to the mangroves of singapore
Molluscs
Peter K L Ng and N Sivasothi (editors)
  Drill
Thais gradata
Family Muricidae


Together with the Ketem (Chicoreus capucinus), these two species are the commonest predators of barnacles and bivalves locally, drilling a hole through the shell of the victim and sucking out the contents using their narrow eversible proboscis.

Members of this family of snails are unqiue in having what is known as an accessory boring organ under their foot, which can produce carbonic acid.
close-up of shell
Chicoreus capucinus
preying on barnacles
Shell height 4.3 cm

close-up of shell
Thais gradata
Dorsal view
Tip of siphonal canal
is a notch at front
end of shell
When this organ is applied to the shell of the prey, the surface is softened by the action of the acid.

The weakened area is then mechanically excavated using their rasping organ (radula) at the end of the proboscis.

close-up of underside of shell showing foot
Thais gradata
Ventral view showing
half-withdrawn animal and
its brown operculum
Shell height 3.7 cm
The process (which may last several hours depending on the shell thickness) is alternated until a hole is made, through which the proboscis is inserted and the victim consumed.

<<Back to molluscs

close-up of egg capsules
Thais surrounded
by its egg capsules

What is mangrove?
Introduction

The Ecosystem

Abiotic
Biotic

Value
Intro
Products
Indirect uses
Potential uses

About Mangroves
in Singapore

History
Mangroves to visit
Conservation
 
From "A Guide to Mangroves of Singapore", Peter K. L. Ng and N. Sivasothi (editors)
Volume 1: The Ecosystem and Plant Diversity and Volume 2: Animal Diversity
Authors: Kelvin K. P. Lim, Dennis H. Murphy, T. Morgany, N. Sivasothi, Peter K. L. Ng,
B. C. Soong, Hugh T. W. Tan, K. S. Tan & T. K. Tan
BP Guide to Nature Series published by the Singapore Science Centre, sponsored by British Petroleum
2001 Raffles Museum of Biodiversity Research, The National University of Singapore & The Singapore Science Centre