Marine snails have a swimming style that corresponds with their shell. The behavior of marine snails has largely remained a mystery, especially in the tropical regions where their diversity is greatest. In a new study published by Frontiers, scientists have discovered that each species of marine snails has its own distinct style of swimming that depends on the shape of their shell.
Throughout the ocean, billions of tiny marine snails make a daily commute from the surface waters where they feed to several hundred meters below where they can rest while avoiding predators.
A team of experts specializing in research at the intersection of fluid physics and biology recorded the movements of tropical marine snails and analyzed them from both perspectives.
Study co-author Dr. David Murphy is an assistant professor at the Department of Mechanical Engineering of the University of South Florida.
“We wanted to answer how the swimming behavior of these beautiful animals is affected by their different shell shapes and sizes. We found that species with a shell shaped like an airplane wing swims faster and is more maneuverable than those with ‘snail-like’ coiled shells,” said Dr. Murphy.
“Understanding the swimming ability of these animals is helping us better understand their ecological importance and distribution in the ocean. Further, as engineers, we hope to learn from the swimming style of these organisms to design a new generation of bio-inspired underwater vehicles.”
Each species examined for the study was found to have a distinct swimming pattern, generally ascending in a saw-toothed spiral at one to 24 body lengths per second, which is the equivalent of the average-sized human male swimming at up to 40 meters per second.
“We conclude that the swimming and sinking behavior of these pelagic snails corresponds strongly with shell shape and size. Tiny snails with coiled shells swim more slowly whereas larger snails with bottle-shaped or wing-shaped shells swim faster because their larger sizes allow them to overcome the effects of water viscosity,” said Dr. Murphy.
“However, swimming speed does not correlate with how far these animals migrate each day, which suggests that light and temperature levels and the presence of predators and prey also play a role. We also found that the sea butterfly with the wing-shaped shell uses its shell to ‘hang-glide’ downwards in order to slow its sinking.”
“It’s absolutely mesmerizing to watch these tiny, delicate animals flap their wings in really complex motions in order to essentially fly through the water. We’re lucky to have high speed cameras that can slow down this motion enough for us to see it. And it’s stunning to think that these sea butterflies are using the same fluid dynamics principles to fly through water that insects use to fly through air.”
The study is published in the journal Frontiers in Marine Science.