It’s one of the wonders of the natural world—to 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.

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Using computer simulations, the study team found that group coordination arises from two factors: the need for a group to stick together and the desire of some individuals to make their own minds up about where to go.

The researchers first programmed their virtual animals with a basic urge to stick as close together as possible without actually colliding. This instinct caused animals to form close-knit, evenly spaced groups, as seen in real mammal herds and fish schools.

Some animals were then programmed to have a preferred direction in mind, as if on a migration route or heading toward a particular feeding area. These animals’ desire to reach their goal was then balanced with an urge to stay with the main group.

During these simulations, the researchers found that it needed only a few individuals to set off together in a certain direction for hundreds of others to follow.

Link: nationalgeographic.com.