Sharks have such bad vision that to them, surfers look the same as seals and walruses, according to a study published Wednesday.
The study published by the Royal Society’s Interface found that great white sharks can barely see colour or distinguish shapes. And young great whites have even worse vision.
The Australian authors of the study wanted to know why sharks bite humans and wondered if maybe they can’t see a difference between humans and animals.
“This is the first study to look at the mistaken identity from the visual perspective of a white shark,” lead author Laura Ryan from the Macquarie University in Sydney, told AFP.
The scientists compared video footage of sea animals, swimming humans and paddling surfers from the white shark’s perspective. A shark would view the potential prey from below.
From the shark’s point of view, “neither visual motion nor shape cues allow an unequivocal visual distinction” between humans and animals, the authors wrote.
That means sharks have a hard time seeing the difference between humans and seals or sea lions.
Shark attacks are relatively rare, the authors said. In 2020, there were less than 60 shark attacks recorded globally. But the study found that people still have a “disproportionate” level of fear of sharks.
The consequences of this fear leads to campaigns like “fever sharks, fever attacks“, which means reducing shark attacks by killing them.
One of the methods used to kill sharks in Australia is placing shark nets around beaches. The nets are not meant as a barrier between swimmers and sharks but to capture and kill the animals.
Shark nets are designed to get sharks so stuck in them that they can’t escape and eventually die. The nets entangle and kill not only sharks but also whales, dolphins, turtles and stingrays.
Ryan said the researchers were now working “to determine if changing the visual cues of potential prey is an effective mitigation technology to protect against white sharks”.
“Greater understanding of why shark bites sometimes happen will hopefully lead to improved solutions that not only prevent shark bites but also don’t endanger other marine wildlife,” Ryan added.
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