National Geographic News
It's one of the wonders of the natural worldto see a flock of starlings pulse, wheel, and ripple as one across an evening sky. Just how do they perform these displays with such precision?
The question thas puzzled scientists for centuries, since many group-living animals have this talent for moving together in a seemingly spontaneous yet highly coordinated way.
Anchovies, for instance, are as synchronized as starlings in their underwater ballets, especially when animated by the presence of predators.
Scientists had thought such graceful mass movements could only be achieved through complex signals.
In the 1930s some even suggested these animals must be able to instantly transfer thoughts to one another.
Or, in the case of birds, perhaps they follow a leader via electromagnetic signals.
Now a new study suggests there's a much simpler and more democratic navigation system that allows flocks, shoals, and herds to travel in unison.
For the study, published in the science journal Nature, researchers used computer models to show that large numbers of animals can move together relatively easily, even when few individuals know what's going on and there is no obvious leader.
"It demonstrates the power of the little guy," said study co-author Daniel Rubenstein, professor of ecology and evolutionary biology at Princeton University in New Jersey. "You don't need avowed leaders, you don't need complex signaling."
The researchers add that their finding may also be useful in understanding human crowd behavior, and in designing robots to explore the deep ocean and distant planets.
Some group-living animals use obvious signals to guide others. For example, after a sortie, foraging honeybees perform an elaborate "waggle dance" back at the hive that tells other bees where to find a good source of nectar or pollen. Ants pass on directions mainly through chemical communication using pheromones.
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