《BBC群体大自然》(BBC Massive Nature)

lovelycrab

Flocks, herds, swarms and schools

    From schools of fish to a swarm of ants, animals exhibit extraordinary
collective behaviour.
    Iain Couzin explains how they do it and what we can learn from this
co-operation.

http://www.bbc.co.uk/nature/animals/features/352feature1.shtml

With a ripple of light, the fish turn, glide and turn again. Like some
animate creature, the school convulses. The predators strike again, two of
them coming through the centre of the group, which is briefly ripped apart.
Then time is suspended as I rotate the group to get a better angle to view
the next attack. Now frozen as three dimensions, I can see the complex
vortex of individuals better. It reminds me of the patterns I made as a
child by passing a magnet over iron filings. With a click of the mouse, the
extra dimension of life is given back to the virtual creatures, and
mesmerising undulations pass across my computer screen once more.

Understanding collective animal behaviour relies on developing computer
models of their motion, such as those I have developed for the BBC's Massive
Nature series. They help us to explain what has been a mystery to scientists
for centuries: how is it possible for fish or birds within a group of tens,
or even hundreds of thousands of individuals, to coordinate their behaviour
so closely?

Leadership problem
So remarkable is this coherence that, in the 1930s, it was suggested that
organisms within such groups must be capable of instantly transferring
thoughts to one another. By the 1970s, it was commonly thought that flocking
birds required a leader to do this. It was hypothesised that there might be
as yet undetected electromagnetic fields generated in the wing muscles or
brain of the leader that could be perceived by other group members. It seems
plausible - just as an orchestra needs a conductor, and so it may seem that
a school of fish or flock of birds requires one, too. Is this the case, or
is there another explanation for such behaviour?

Another example of collective biological organisation that has long
fascinated people is the complex social existence of many insects. As the
first Lord Avebury, John Lubbock, noted in 1882, in Ants, Bees and Wasps:
\"When we consider the habits of ants... their large communities and
elaborate habitations; their roadways... it must be admitted that they have
a fair claim to rank next to man in the scale of intelligence.\" We know that
such insects are not intelligent, at least not in a way comparable to
humans. But if intelligence is not governing complex collective behaviour,
what is?



On TV: the related six-part series Massive Nature was shown in July 2004. In
the course of researching for the series, the programme team worked with the
Wildfowl and Wetlands Trust on the migration of lesser flamingos. Follow
their satellite tracking project for the latest news.