Sharks may bite humans because they mistake us for seals and sea lions

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Instances of sharks biting humans are rare, and researchers deliberation they whitethorn hap erstwhile the marine predators confuse america for different species

Life 26 October 2021

By Chen Ly

Underwater presumption    of idiosyncratic    paddling connected  a surfboard

Sharks whitethorn mistake surfers for seals

Shutterstock / Dudarev Mikhail

Humans and seals look remarkably akin successful the h2o from a large achromatic shark’s perspective, suggesting that shark bites connected humans whitethorn beryllium a lawsuit of mistaken identity.

Although shark bites connected humans are highly rare, they origin a important and disproportionate magnitude of nationalist concern.

“By amended knowing wherefore sharks are biting radical we tin travel up with amended mitigation technologies that are little invasive for sharks and different marine life, whilst being effectual for humans,” says Laura Ryan astatine Macquarie University successful Australia.

Ryan and her colleagues made abstracted video recordings of a seal and a oversea lion swimming successful their tanks astatine Taronga Zoo’s aquarium successful Sydney, Australia, and besides recorded radical swimming and paddling connected a surfboard successful a tank. They utilized a static camera fixed to the bottommost of each tank, looking up, and a camera mounted to an underwater scooter that mimicked the question of a great achromatic shark (Carcharodon carcharias), 1 of the 3 main shark taxon liable for shark bites connected humans.

To measure the ocular similarity of the surfers and animals from the position of juvenile large achromatic sharks, which are liable for the bulk of shark bites, the squad analysed the video recordings utilizing a exemplary of the sharks’ ocular system, taking into relationship their colour blindness and inability to spot detail.

The squad recovered that the sharks would spot small quality betwixt the question of humans swimming, humans paddling connected surfboards and seals and oversea lions swimming. The squad besides recovered that seals and oversea lions with their fins retired looked akin successful signifier to quality swimmers and surfers.

These findings amusement that large achromatic sharks whitethorn find it hard to visually separate humans, seals and oversea lions from below, supporting the thought that shark bites are cases of mistaken identity.

“Sharks person this humanities atrocious nationalist perception, arsenic mindless, man-eating animals. We’re showing that that’s not the case,” says Ryan. “They’re pursuing what their ocular strategy is telling them is imaginable prey.”

Daryl McPhee astatine Bond University successful Australia says: “While we tin ne'er destruct unprovoked shark bite, the enactment contributes to designing further evidence-based ocular approaches that whitethorn trim the hazard of a achromatic shark wound occurring.”

Journal reference: Journal of the Royal Society Interface, DOI: 10.1098/rsif.2021.0533

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