Directions for teachers: Ask students to read the online Science News article “Here’s the physics of why ducklings swim in a row behind their mother,” which details how baby ducks save energy by surfing their mom’s waves. A version of the article, “Why baby ducks swim in a line,” appears in the November 6, 2021 issue of Science News.

1. What did scientists recently discover about swimming baby ducks?

Ducklings that swim in a straight line behind their mother can save energy by riding on waves she creates.

2. How does the finding build on previous research? Explain what was previously found.

Previous measurements of duckling metabolism showed that baby ducks saved energy when swimming behind a leader. However, the physics behind the energy savings remained an open question.

3. How did scientists make the new discovery?

Researchers used computer simulations of waves that ducks make while swimming.

4. How does the physics of ducklings swimming in a line behind a leader compare with the physics of a duckling swimming by itself?

The researchers calculated that a duckling swimming in the sweet spot behind its mother experiences a push from its mother’s waves, and that each duckling in a line passes along waves that the duckling behind it can surf. A duckling swimming by itself, on the other hand, kicks up waves that resist its forward motion. Instead of a push, the lone duckling experiences wave drag.

5. What happens if ducklings fall out of line?

Swimming gets harder.