The remora fish’s sticky disc was the perfect solution, as it includes built-in redundancies that allow it to stay adhered to surfaces even with partial contact.

That research revealed that remora fish stick to surfaces very much like a suction cup does, with a flexible oval ridge of soft tissue that creates a tight seal.

As water is squeezed out of the gap between the remora and its host, suction holds it in place.

The surface of the remora fish’s disc is also covered in ridges aligned in columns and rows called lamellae (similar to the ridges you can feel on the roof of your mouth) that can be extended through muscle contractions to engage tiny spinules that further grip onto the host.

The team was able to create an artificial version of the remora fish’s suction disc through a four-layer approach.

Installed atop the submersible drone, the suction mechanism allows it to adhere itself to a variety of surfaces, even if they have a rough texture, aren’t perfectly flat, or have a smaller surface area than the suction mechanism.

Like a remora fish, the drone could, at least in theory, find itself an underwater host (one not immediately scared away by its spinning propellers) and attach itself for a free ride, requiring just the suction mechanism to be powered, which is a minimal drain on its onboard batteries.