Sharks attack surfers who mistook seals

Pioneering research has confirmed theories that when great white sharks bite humans, this may be a case of misidentification.

To reach this conclusion, Macquarie University tested a simulated model of “shark vision” on the swimming patterns of humans, seals and sea lions.

“Surfers are the group most at risk of fatal shark bites, especially small white sharks,” says lead author Dr. Laura Ryan, a postdoctoral researcher in animal sensory systems in the Laboratory of Neurobiology at Macquarie University.

Great white sharks, along with bull and tiger sharks, account for by far the majority of attacks on humans.

“We found that surfers, swimmers, and footmen (seals and sea lions) on the ocean surface are indistinguishable from a white shark looking from below, because these sharks cannot see details or colors,” he says.

Ryan, who remains an avid surfer despite being immersed in shark bite research, says this study will help scientists better understand why some sharks bite humans.

In response, scientists in the Neuroscience Laboratory are working on non-invasive vision-based devices to protect surfers and swimmers from shark bites.

Ryan says the latest study, published in the journal The Royal Society Interface, was a hands-on test that built on years of teamwork to understand how sharks see, by exploring the neuroscience of white sharks’ visual systems.

The team compared underwater videos of rectangular buoys, seals, sea lions swimming with different movements, and humans paddling surfboards of varying sizes in a large aquarium at Taronga Zoo, with fixed and moving cameras pointed toward the surface of the water.

“We connected the GoPro to an underwater scooter and tuned it to move at the cruising speed typical of predatory sharks,” says Ryan.

Back in the Macquarie Neurobiology lab, the team relied on extensive data in shark neuroscience to apply filters to video images and then created modeling software to simulate the way the great white shark processes the movements and shapes of different objects.

“I didn’t realize being a scientist would involve so much coding,” Ryan admits, but the results were illuminating: For young white sharks, when humans swim and paddle surfboards, they look a lot like seals and sea lions. .

Smaller surfboards were difficult to distinguish from theropods, so they might represent more tempting prey than the longboards or even stand-up paddleboards of white sharks, which generally target cubs and young adults.

Most sharks are likely to be completely color blind, and the main visual cue for large eggs is their silhouette shape, so colors on plates and diving suits are unlikely to alter sharks’ impressions. Floating superhuman sharks.

However, researchers are now exploring other ways to change the way sharks see different silhouettes, including the use of LED lights.

“Sharks use a variety of sensory cues to distinguish different objects and focus on their food, and these cues vary in sensitivity between shark species,” Ryan says.

Highly sighted, juvenile white sharks are more dangerous to humans than larger, larger white sharks, which have better vision.