For the first time, researchers have documented great white sharks using their dorsal fins to physically investigate objects at the ocean’s surface. The findings, published September 9 in the Journal of Fish Biology, were made during drone surveys off California’s coast.
The study details two separate observations of Carcharodon carcharias exhibiting this previously unrecorded behavior. In one instance near Goleta, researcher Carlos Gauna filmed a shark approaching an unidentified object at the surface. The shark initially bumped the object with its snout—a common investigative action—then swam past it and rotated its dorsal fin on its axis to bat the object before swimming away and returning its fin to its original position.
A second observation off Santa Barbara showed another shark swimming directly at a surface object, rotating its dorsal fin toward it upon contact, then moving the fin back upright.
Researchers explained that as white sharks swim forward, they create a bow wave that can prevent direct snout contact with objects at the surface. “The dorsal fin is the next part of their bodies that can provide a ‘tactile confirmation,’” according to the study.
The team noted that these observations confirm both the flexibility and dynamic function of white shark dorsal fins. They suggest that sharks may use their fins for investigative purposes through physical contact or as an automatic response to encountering objects.
“Another possibility is that the dorsal-fin movement is purely a response to the contact with the object,” researchers said. “Nonetheless, similar to the first scenario, the dorsal fin rotated on its axis showing that this functional capability and behaviour occurs in multiple individual white sharks.”
The research was conducted by Carlos Gauna and Phillip C. Sternes.
This story was originally published September 12, 2025 at 4:14 PM.
