http://www.bath.ac.uk/news/2007/1/8/bigbrainedbirds.html
Press Release - 08 January 2007
Big-brained birds survive better in nature
EMBARGOED UNTIL 00.01hrs GMT WEDNESDAY 10 JANUARY 2007
Birds with brains that are large in relation to their body size have a
lower mortality rate than those with smaller brains, according to new
research published in the journal Proceedings of the Royal Society B:
Biological Sciences today.
The research provides the first evidence for what scientists describe
as the ‘cognitive buffer’ hypothesis - the idea that having a large
brain enables animals to have more flexible behaviours and survive
environmental challenges.
This theory was first put forward to answer the puzzle surrounding why
animals, including humans, would evolve a larger brain, given the
‘cost’ associated with developing and maintaining a larger brain.
The researchers compared the brain size, body mass and mortality rates
in over 200 different species of birds from polar, temperate and
tropical regions.
They found that birds with larger brains relative to their body size
survived better in nature than birds with small brains. This may
explain why, for example, birds with small relative brain sizes, such
as pheasants, find it harder to avoid a moving car than those with
larger brain size, such as magpies.
“The idea that large brains are associated with reduced mortality has
never been scientifically tested,” said Dr Tamas Szekely from the
Department of Biology & Biochemistry at the University of Bath.
“Birds are ideally suited for such a test, as they are one of the only
groups of animals for which the relationship between large brains and
enhanced behavioural response to ecological challenges is best
understood.
“We have shown that species with larger brains relative to their body
size experience lower mortality than species with smaller brains,
supporting the general importance of the cognitive buffer hypothesis in
the evolution of large brains.”
The researchers made allowances for factors which may have accounted
for variations in mortality rates, such as migratory behaviour,
competition for mates and chick behaviour.
“Our findings suggest that large-brained animals might be better
prepared to cope with environmental challenges such as climate change
and habitat destruction,” said Dr Szekely, who worked with researchers
from the Autonomous University of Barcelona (Spain), Pannon University
(Hungary) and McGill University (Canada) on the project.
“This is supported by other research which has shown that large-brained
birds are more successful in colonising new regions and are better at
surviving the changing seasons.”
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