Have you ever seen baby ducks or geese swimming in line behind their mother? They’re so cute! But why do they do that? Is it to keep everyone organized and safe? Or is it to make swimming easier for the babies? We wanted to figure out how swimming in a line benefits the ducklings. We hypothesized that this formation saves the ducklings energy. We created a mathematical model to test our hypothesis. We realized that the most energy-efficient place for them to swim is behind their mother. And if they swim at specific positions, the waves created by their mother or passed along by the other ducklings propel them forward. This saves lots of energy!