Physicist Zhiming Yuan was at the park with his daughter when she asked him why ducklings tend to swim in a line behind their mother. Yuan, who works at the University of Strathclyde in Scotland, thought the formation might help reduce drag. This slowing force is caused by the water pushing against the ducks as they swim.

To find out more, Yuan created a computer model showing ducks swimming in different configurations. A mama duck generates waves as she swims. Yuan discovered that the ducklings behind her can ride the waves, reducing drag and making it easier for them to paddle. Even better, according to Yuan’s model the wave energy also passes down the line from duckling to duckling. This creates a boost that pushes each little duck forward!