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Most of the time, we only have the opportunity to observe shark bites on cage bars. But what does a great white attack look like from the perspective of one of its prey? Thanks to a remote-controlled underwater vehicle equipped with six cameras, scientists were able to closely observe the hunting techniques of these impressive sharks in their natural environment.
The small torpedo-like robot was launched near Guadelupe Island, located off the west coast of Mexico.
A new observation technique
The cameras filming the front, back and sides of the REMUS SharkCam were to provide researchers with a close-up, panoramic view of the white sharks. But upon recovering their vehicle, they realized that the large predators had not remained unmoved by this small intruder, whose elongated shape can be compared to that of a seal.
Before sending the REMUS (Remote Environmental Monitoring Unit) on a mission, the Woods Hole Oceanographic Institution team marked a few white sharks in the area using tags that could be picked up by the underwater vehicle up to 100 times. meters deep. Once received, the SharkCam can locate these signals and track them, approaching the animals for optimal 360° vision.
A white shark attack from the perspective of its prey
But the researchers got much more than they expected. Whether to defend their territory or simply to feed, sharks have shown great interest in the 2.3 meter long torpedo. The images are impressive: we can see sharks emerging from the depths to bite the camera, a technique also used to catch seals.
During predatory attacks, sharks hide in the shadows, beneath their prey, before emerging from underneath and biting, scientists explain. The cameras allow us to observe a characteristic specific to the great white shark. When it attacks, it must protect its eyes from possible shocks and defense attempts by its prey.
But unlike many other species, the great white does not have a nictitating membrane to cover its eyes. He must therefore roll them backwards in his eye sockets to protect them.
Better understand great white hunting techniques
When the REMUS was brought to the surface, the researchers were surprised by what they were able to see: huge teeth marks on a large part of the vehicle. According to one of them, even a human equipped with a chisel could not have inflicted such injuries on REMUS. In total, a dozen interactions between the shark and the underwater vehicle were recorded.
The team hopes that these exceptional images and future REMUS dives will allow them to better understand how sharks hunt their prey in their natural environment. The robot has also filmed basking and white sharks off Cape Cod, and scientists plan to use it to track other large marine animals, like turtles.
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