Sea butterflies’ shells determine how the snails swim
Aquarium videos show species rise and sink at different angles and speeds
![image of a sea butterfly on a black background](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2020/09/090420_MT_sea-butterfly_feat.jpg?fit=1028%2C579&ssl=1)
Different species of marine snails known as “sea butterflies,” such as Diacria trispinosa (shown), have distinct swimming styles that depend on the sizes and shapes of their shells.
David Shale/Nature Picture Library/Alamy