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New Swarm Theory: The Weak Can Lead the Strong

Ker Than
for National Geographic News
February 11, 2009
 
They might not win many presidential elections, but mavericks are often leaders among flocks of birds, herds of beasts, and other creatures, a new swarm theory says. (See locust swarm pictures.)

A new computer model suggests animals don't need to be fast or strong to lead their swarms, only willing—or desperate enough—to break from their neighbors and go their own way.

Swarm "leaders are not necessarily the weakest and most vulnerable, but they can be," said study team member Larissa Conradt of University of Sussex in the United Kingdom.

The model suggests that a few very hungry birds in a well-fed flock of thousands can alter the flight path of their entire group simply by veering off to search for food.

Creatures that fly, swim, and run together are hardwired to stay together, Conradt explained.

Swarm living provides protection against predators and a convenient supply of potential mates, so members rarely perform actions that could tear the group apart.

"If some group members are desperate to reach their optimal destination, while others care relatively less whether they reach theirs or not, the desperate ones will lead," said Conradt, whose new research will be detailed in an upcoming issue of the journal American Naturalist.

Biologist David Sumpter studies collective animal behavior at Uppsala University in Sweden and did not participate in the research.

The new study is interesting, Sumpter said, because it shows how "a small number of highly motivated leaders can manipulate the group dynamics significantly for their own purposes but without destroying the cohesive motion of the flock."
 

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