BBC Knowledge Asia Edition 3

Cornwall by volunteer citizen scientists, many of whom are

birdwatchers happy to add variety to their patch-watching.

It’s all very impressive – Sue’s personal passion and skill, and

the colossal spreadsheets of data. But is it scientific? “I was very

concerned about scientific rigour,” Sue says. “Every record is

archived – the dates, the pictures, the matches – so anyone can

go back and independently check that there’s no mistake.”

The identification protocols that Sue has developed with

the University of Exeter require five matching coat patterns

in the same relative positions, ideally on both sides of the

body, with no obvious inconsistencies elsewhere before a

match is confirmed by two experienced researchers. The

system allows for the fact that seal appearances can change

depending on the condition of the fur (wet or dry, moulting

or not), age and the appearance of scars.

Though the grey seal is the largest mammal breeding in

Britain, its ecology is relatively little known. This is a familiar

problem for marine biologists, whose subjects spend a large

part of their lives hidden from view. Big budgets are needed

to deploy GPS tags, SMS transmitters, data-loggers and

radio-telemetry to follow seals, whales, sharks and sea turtles.

In comparison, using photos, mostly taken from the shore

but sometimes from boats, is undeniably low-tech.

It’s also low-cost and – most importantly – non-invasive:

no seal has to be caught and handled. And because the

system that Sue has developed enables seals to be tracked

for their entire lives, it reveals more about individuals than

any other method and builds knowledge on abundance,

habitat use, migration, breeding and survival rates, as well as

behaviour such as feeding, vocalisations and personality.

One of the first conclusions of Sue’s work is that Britain’s

grey seals don’t live all year in static colonies. “You might

see 99 seals on a beach one day, and 99 the next, but very

few will be the same individuals. Seals come and go, using

locations like motorway service stations.”

“One of our volunteers spent two years photographing seals

every week without finding a match,” she continues. “Another

built up a catalogue of 150 animals before one turned up twice.

But the buzz when you finally get a match is amazing.”

SEAL SOCIABILITY

Clearly seals are gregarious – on land they’re seldom seen

alone. But given the independence of their movements at

sea, are they sociable? Sue is sure that they recognise one

another: “They greet by sniffing each other’s faces and ears.

The reactions vary from what looks like affection through

tolerance to recoil, suggesting they can recognise other

individuals and recall past encounters.”

Another uncertainty about grey seals is just how many

there are, though we know that Britain is home to over

a third of the world

population, and that

there are probably two

or three times more grey

seals in British waters

than common ones. Data

from the Sea Mammal

Research Unit based at

the University of

St Andrews also

CLOCKWISE

FROM TOP LEFT:

Sue Sayer of the

Cornwall Seal

Group Research

Trust identifies

a grey seal; grey

seal pups gain

weight rapidly

thanks to their

mother’s milk,

which contains

60 per cent fat;

Sue photographs

grey seals on

a survey trip

Though the grey seal

is the largest mammal

breeding in Britain, its

ecology is relatively

little known