The shark appears to be chasing the drone’s shadow, does it not? Photo: YouTube//Screenshot
In physics, there’s a theory called the “Observer Effect.” There’s a variation of it in psychology, too, but that’s called the “Hawthorne Effect.” In short, it’s a theory that things or people act differently when they are being watched. If it’s taken into account, it can make research tough, because there’s no way of knowing whether something is acting differently when it’s not being watched because… well, it’s not being watched. With animals like sharks, it’s tough to know if they know they’re being watched, and whether that changes the way they do things. But Carlos Gauna, a guy who watches sharks a LOT, recently discovered some pretty unbelievable behavior.
“Ever since I spotted my first great white shark,” Gauna says, “I’ve been wondering: ‘can they see the drone above the water?’ In the water, it’s a different story. They can feel the electrical currents; they can see the camera. But from above, can they sense the drone?”
The video you see here dives into whether or not they can. Great whites’ senses are different than ours. “Great whites — and sharks in general — seem to have super powers when it comes to senses,” Gauna says. “Their first super power is electroreception.”
Sharks have little jelly filled tubes that open on the surface of their skin. Inside, each tube ends in a bulb known as the ampulla. If you remove the skin from the head of a shark, hundreds of these bulbs can be seen.
That jelly is conductive, allowing them to sense voltage differences around them. They’re used to help sharks hunt, which is super helpful if, for example, something delicious is hiding beneath the sand. But a flying drone does not transmit any electrical signal into the water.
“Above the surface, this sense is essentially useless,” Gauna explains. “…Unlike marine mammals, sharks don’t have external ears or binocular vision, so their ability to see and interpret what’s above the water is still a mystery.”
Gauna believes, however, that it’s likely that the sharks may be able to sense the drones, not from the sound or the smell, but from the shadow they cast. This is because sharks are particularly good at seeing contrasting colors, like a seal on the surface. This footage appears to show a great white chasing the shadow of a drone like a cat chasing a laser pointer.
“It’s not something I ever expected to discover,” Gauna says. “This behavior really made me wonder if there may be some useful applications for shark deterrent methods that could be based on visual cues.”
