Ducklings swim in line behind their mother to reduce drag and propel themselves forward

The sight of a line of ducklings paddling behind their mothers is something many of us are used to seeing in rivers and ponds.

But why do ducklings swim in this formation?

Scientists at the University of Strathclyde attempted to answer this question and found that swimming in a line behind their mother helps reduce drag and actually propels the ducklings forward.

The findings not only shed light on the behavior of ducklings, but could also help revolutionize shipping, according to the team.

Dr Zhiming Yuan, who led the study, said, “These principles could be applied to the design of modern freight transport vessels, such as a river train, to carry more cargo without additional fuel cost.”

In the study, the researchers used a mathematical and numerical model to understand why ducklings evolved to swim in line behind their mothers.

Their analysis revealed that this training helps the ducklings benefit from both “wave over waves” and “wave passing”.

When the first duckling swims behind its mother, in what the researchers describe as a soft spot, a phenomenon called “destructive wave interference phenomenon” occurs.

Thanks to its positioning, the force of the waves acting against the duckling as it paddles in the water, called drag, turns into a positive movement, which means that the baby bird is actually propelled forward.

This effect is then passed on to the rest of the ducklings in the lineage, the researchers said.

By the time it reaches the third duckling, the wave drag tends towards zero, with dynamic equilibrium achieved.

Each following duckling then acts as a wave ferryman, transmitting the energy of the waves to the next one, without any loss of energy.

Dr Yuan explained, “Surfing and passing waves are probably the main reasons for the evolution of waterfowl swimming training.

“This study is the first to reveal the reasons why the training movement of waterfowl can preserve the energy expenditure of individuals.

“Our calculations provide new information on the mechanisms of swimming in formation.”

In addition to making it easier to glide through the water, researchers believe the benefits of moving in formation may also influence the primitive instincts of ducklings.

In their study, published in the Journal of Fluid Mechanics, the researchers explained: “The benefit received when moving in formation on the surface of the water can also influence the primal instinct of ducklings, causing ducklings to follow unconsciously. all moving objects that they see during a period on the ground, because they are more sensitive to the imprint.

“Although the mechanism of imprinting has not yet been fully understood, the study here sheds light on the importance of fluid mechanics on animal behavior and, potentially, on evolution.”