Despite their bad reputation, sharks are rarely out to get humans. New research has now confirmed the “mistaken identity theory” – when they bite people, it’s probably because they think the human is a seal. A lose-lose situation all round.
Jaws really did sharks dirty, setting the soundtrack to anxious swimmers everywhere trying to enjoy the open ocean, legs kicking for all its underwater inhabitants to see. The negative PR job, combined with inflammatory and poorly-worded headlines, has left many of us anxious about shark attacks when in reality you’re almost more likely to be killed during a gender reveal party than in the jaws of these apex predators.
When sharks are on the prowl, what they’re expecting to come across are other marine animals that are a staple on their menu. It figures, then, that when they see an oblong shape with apparent flippers on either side they could easily get a surfer confused for a tasty pinniped – so are they really the blood-thirsty hunters of humans the media has led us to believe?
A new paper published in the Journal of the Royal Society Interface adopted a shark’s-eye-view of the underwater environment to assess if shark attacks could be a simple case of mistaken identity. Scientists from an international group of universities clubbed together to create a virtual white shark visual system, enabling them to see the world through the eyes of a shark. They looked to the Taronga Zoo for footage to test out the system, depicting scenes of seals and humans swimming, plus people paddling on surfboards.
“Until now, the potential similarity between humans and seals has been assessed based on human vision,” said lead author Dr Laura Ryan in a statement. “However, white sharks have much lower visual acuity than us, meaning they cannot see fine details, and lack colour vision. In these experiments, we were able to view the world through the eyes of a white shark.”
Their results showed that it’s entirely likely that sharks can’t tell the difference between a human and a seal, though admittedly that doesn’t mean it’s the case in every attack. Furthermore, the mistaken identity theory seems to be most relevant to juvenile sharks, thought to be involved in a large proportion of attacks on humans. This is probably linked to the fact that at this age, their jaws are hardening, meaning they can begin to take on larger prey like seals. With their lack of seal hunting experience, they might screw up on their early attempts and bite the wrong thing.
The findings are of great interest to science and the general public, as while shark bites are rare, the authors report they are increasing in frequency as the human population continues to grow and more and more of us are spending time in sharks’ hunting grounds. The solution to this requires sophisticated measures that won’t harm the shark population – not only because they are magnificent creatures, but because many of them represent keystone species in the marine environment, without whom the ecosystem could become unstable.
“Greater understanding will hopefully lead to improved solutions that not only prevent shark bites but also don’t needlessly endanger other marine wildlife,” said Ryan. “In fact, the findings of this study have inspired the design of non-invasive vision-based shark mitigation devices, which are currently being tested.”
3,000-year-old remains found in Japan earlier this year are thought to represent the oldest known example of a human getting chomped by a shark. Poor guy probably had no idea he looked like a seal.