- If you thought fish were cold, wet creatures who forget
everything in three seconds flat, think again. Scientists have found they
are fast learners, carry mental maps around in their heads - and can retain
memories for months.
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- Swimming gormlessly around in their bowls or tanks, fish
have long been dismissed as dunces compared with "higher" animals
such as rats, cats, dogs and primates. This view is now being challenged
by findings that could re-ignite the debate over the cruelty of angling.
Tests on fish in aquaria at Oxford University have shown that despite their
tiny brains, they possess cognitive abilities outstripping those of some
small mammals.
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- Dr Theresa Burt de Perera made the discovery using blind
Mexican cave fish, which rely on subtle changes in pressure to detect the
presence of objects around them.
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- In experiments, Dr Burt de Perera found that the fish
did more than merely avoid bumping into objects in their tank. They built
a detailed map of their surroundings, memorising the obstacles in them
within a few hours. Once stored in their brains, the fish used their "mental
map" to spot changes in the obstacles around them - a feat that defeats
hamsters.
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- In one test, involving obstacles arranged in a specific
order, the fish proved capable of memorising the order and quickly spotted
when Dr Burt de Perera swapped obstacles around.
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- According to Dr Burt de Perera, the findings - which
appear in the current issue of the Proceedings of the Royal Society - show
that fish are under-estimated.
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- "The public perception of them is that they are
pea-brained numbskulls that can't remember things for more than a few seconds,"
she told the Telegraph. "We're now finding that they are very capable
of learning and remembering, and possess a range of cognitive skills that
would surprise many people."
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- Laboratory tests on other fish have found that they can
store memories for many months, confounding the belief that they forget
everything after a few seconds.
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- Dr Culum Brown at the University of Edinburgh has found
that Australian crimson spotted rainbowfish, which learnt to escape from
a net in their tank, remembered how they did it 11 months later. This is
equivalent to a human recalling a lesson learnt 40 years ago.
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- Dr Burt de Perera's findings have been welcomed by fish-lovers
as proof that their pets can do more than blow bubbles. "They are
totally misunderstood," said Karen Youngs, the editor of Practical
Fishkeeping. "We know from our readers that fish can recognise their
owners, and some will go into a sulk if someone else tries to feed them."
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- Mrs Youngs added that the research may mean that fish-owners
have to make their aquaria a bit more interesting for their occupants:
"We know that fish such as oscars do enjoy having a table-tennis ball
to bash about."
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- Mounting evidence for fish intelligence is likely to
re-ignite the controversy over angling, which has focused mainly on whether
fish can feel pain. "This research moves the debate along, by showing
that fish aren't just swimming vegetables," said Dawn Carr, the director
of People for the Ethical Treatment of Animals. "The more we find
out about fish, the less likely people are to feel comfortable about impaling
them on a hook for fun."
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- Anglers dismissed such views. "Their intelligence
just adds to the interest - it would be awful if people were only catching
fish that were stupid," said Rodney Coldron, a spokesman for the National
Federation of Anglers. "I think it might attract more people to fishing,
by showing it's more of an even contest."
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