Have you ever seen a flock of birds dive and weave through the air? It’s like they all know where to go.
Large flocks of starlings that fly together are called a murmuration. Maybe you’ve seen videos of them.
Schools of fish do the same thing in the water, twisting and turning, sometimes to avoid bigger fish trying to eat them.
As birds and fish move together in such big crowds, it’s amazing that they never seem to bump into each other.
Scientists wondered why. What they found is that the birds and fish create wakes in the air and water. A wake is like the waves made behind a boat when it travels through the water. Planes and cars make invisible wakes through the air.
When birds and fish make wakes while flying or swimming, the bird or fish in the back kind of surfs. The scientist found that if a bird in the back is slower, the wake will give it a push forward. If the bird following is going too fast, it will be pushed back by the wake from the bird in front. The same goes for fish.
"These mechanisms create a few 'sweet spots' for a follower when sitting behind a leader," said Jun Zhang, a professor at New York University.
Bicycle racers often use this to their advantage, hanging behind a rider in front to make their pedaling easier. This is known as drafting.
The scientists are hoping to use their study to find new ways to create energy from rivers or wind.
— Brett French, firstname.lastname@example.org