most, a snail is something to gingerly pluck out from a plant
pot and toss into the horizon. But to one young Sri Lankan
scientist in England, these slimy, unassuming creatures offer
the key to some of nature’s most pressing questions.
Twenty -eight-year-old Dinazarde Raheem has
spent the last 11 years of her life investigating Sri Lanka’s
land snails: Examining the animals in their home environments
and making collections; studying and verifying available
information; researching new species. Her work has helped
reinforce what others have already, to an extent, established —
that Sri Lanka has a high, even staggering, number of endemic
The total number of species already known is
approximately 250, with the greatest diversity found in the
rainforests of south-western Sri Lanka. Of these, over 80 per
cent are unique to Sri Lanka. And Dinazarde estimates that she
may have discovered at least 50 more new species during the
course of her fieldwork. These are soon to be formally described
and catalogued. There may also be other new species in parts of
the country that haven’t yet been surveyed.
Together with Fred Naggs — biodiversity and
conservation officer at the Natural History Museum (NHM) in
London, where Dinazarde is currently based — she has produced
glossy colour guides of Sri Lanka’s snails in Sinhala, Tamil and
English and is in the process of creating a CD-ROM of all
described Sri Lankan species, complete with illustrations. They
have also helped establish a reference collection of land snails
at the Department of National Museums and another at the
University of Peradeniya.
What drives her? "It’s curiosity really," she
grinned. "That’s why I do it. I’m fascinated by natural history
and curious to find out what’s happening in Sri Lanka in terms
of the land snail fauna."
Snails as an indicator
"Snails act as an indicator because they share
their forest habitat with lots of other species," she enthused.
""They can tell us how animals in forests might be coping or not
coping with changes in forest cover. They can provide clues
about how communities of species are structured. I’m using
snails as a model to answer fundamental questions about the
It sounds like a language only biologists can
understand but Fred volunteered to explain. Land snails can
offer us a view of the past, he said. Their shells often remain
preserved for long periods of time and can yield clues about the
earth’s past climate. Land snails such as the large and
beautiful tree snail Acavus have changed little since the
world’s southern continents were joined together as the
supercontinent Gondwana over 100 million years ago. They can
provide insight into the rate of evolutionary change.
Scientists may also find interest in why Sri
Lanka has such a large number of endemic snails — species that
are not even found in India. Although the island does share many
species of mammal, bird and reptile with the neighbouring
country, this does not extend to snails. "That’s got to mean
something," observed Fred.
Lack of interest
Fred and Dinazarde lament that, despite being
fascinating and often beautiful creatures, snails are a
neglected species in Sri Lanka. They are usually reviled for
destroying plants, although Dinazarde pointed out that none of
the major pest species are native to Sri Lanka — the
introduction of exotic slugs and snails is a serious and growing
"Next to being asked how to kill garden snails,
the question we are most often asked is ‘what use are they’?"
Fred and Dinazarde write in one of their colour guides. "This
implies that the existence of organisms needs to be justified in
terms of human values and human exploitation; it is not a view
Dinazarde’s own interest in snails developed a
few months after she left school, when she spen t a year
rummaging in Sri Lankan forests with eminent naturalist the late
P. B. Karunaratne — ‘Karu’, to his friends. A friend of the
family, he was involved in a five-year survey of forest areas —
studying various animal groups like mammals, birds, amphibians,
reptiles and butterflies — and he had encouraged the young girl
to become one of his field assistants. She moved fresh from her
advanced level examination into Sri Lanka’s wilderness.
An old girl of Bishop’s College and Colombo
International School, Dinazarde later shifted to Imperial
College, London, for a degree in biology. Snails became an
important focus of interest during her time as an undergraduate.
She started visiting the neighbouring NHM because she knew it
had Sri Lankan collections. "I wanted to identify the snails I
had seen while working with Uncle Karu," she said.
The NHM collection
How had a museum in Britain acquired such a
large collection of Sri Lankan snails? The answer lies with the
Brits who roamed the country during colonial times, many of whom
had strong naturalist inclinations. "We do have a massive
collection of specimens, mostly put together during the 19th
century," said Fred. "Britain was then a major influence in the
world and Britons took their passionate interest in natural
history wherever they went." Including ‘Ceylon’. And their zeal
was not confined to snails.
"If anybody wants to do any work involving
animals in Sri Lanka, the chances are that they will have to
refer to our collections here," Fred said. "This is especially
true where it concerns groups like snails."
These amateur British naturalists gathered
samples of flora and fauna, trying to identify species and glean
whatever information they could about them. This led to the
formation of private collections around the world; these later
came to the United Kingdom when their owners retired and
returned home. Many of them left their collections as private
legacies and the museum has largely built up its own collections
from these private individuals. The museum’s haul often forms
the basis of diverse study programmes.
Among those collectors who lived and worked in
Sri Lanka were several members of the Layard family. The two
Layard cousins, Edgar and Fredrick, made a particularly
significant contribution to the study of Sri Lankan natural
history and to our basic understanding of how many species there
are in the country — not only of snails but of butterflies,
A large number of the snails they gathered are
now at NHM. Layard’s Road in Colombo is named after another
member of this family.
"It was fun"
In her first year and also immediately after her
degree, Dinazarde and some friends conducted two field
expeditions to Sri Lanka with funding from the university. Once
again, she was trudging through forests, surveying distribution
and collecting specimens. And it was quite enjoyable, she
"Sometimes we camped," she said. "Sometimes we
climbed hills and often we walked quite deep into the forests.
We saw birds, waterfalls, beautiful trees`85. It was fun."
Following graduation, Dinazarde started working
part-time at NHM. Soon afterwards, she became involved in a
collaborative project on Sri Lankan land snails between the NHM,
Department of National Museums Sri Lanka and the University of
Peradeniya. The project was funded by the UK government’s Darwin
Initiative. It involved field research on land snails and their
distribution; the establishment of land snail collections in Sri
Lanka; and the publication of scientific and popular guides on
the island’s land-snail fauna.
Launched at the 1992 UN ‘Earth Summit’ in Rio de
Janeiro, Brazil, the Darwin Initiative seeks to help safeguard
the worlds’ biodiversity by drawing on British strengths. It
aims to assist countries that are rich in biodiversity but poor
in financial resources by increasing their capacity for
understanding and conserving their own biodiversity.
During the three-year Darwin project, Dinazarde
studied land snails in different forests of Sri Lanka’s wet, dry
and intermediate zones. This was followed with more detailed
research in threatened forest patches of the wet lowlands. The
latter study, which forms the focus of her PhD, looks at how
forest snails deal with forest loss and land use change. For
this, she explored lowland rainforests in the Ratnapura,
Kalutara, Galle and Matara districts.
Over the next few years, Fred and Dinarzarde
hope to publish the results of these investigations as popular
articles, guides and as research papers in scientific journals.
Currently completing her doctoral studies at the
University of Cambridge and NHM, Dinazarde has gained valuable
insight during the past few years. She has discovered, for
instance, that some of the people who knew most about forests
were the villagers who lived around them. "There are still local
people with an incredible knowledge of forest plants and the
uses of forest plants," Dinazarde said. "They don’t know them by
scientific or botanical names. But they have a sophisticated
system of classification which is quite impressive."
"We have come across people who are quick in
picking up even Latin names," she continued. "A lot of people
are desperate for information."
Dinazarde now hopes that more can be done to
provide updated and scientific information on Sri Lanka’s plants
and animals to people in rural areas.
"I think long-term conservation depends on
empowering local people, people who actually live close to
forests," she explained. "They are in the best position to
protect those areas. I feel the solution lies in getting local
people involved in managing their own resources."