Ever wondered what a shark sees when it’s on the hunt? Well, now you can see it for yourself (you'll have to provide your own Jaws theme tune though).
Scientists have captured great white sharks hunting in kelp for the first time – something they (and possibly seals) hadn’t thought they did – and the footage is amazing.
It’s the first time this behavior has been observed in great whites and helps answer some long-sought-after questions.
Compared to animals on land, getting up close and personal with creatures of the deep (especially toothy ones) can be quite hard. But PhD student Oliver Jewell of Murdoch University, Australia and colleagues managed to attach cameras to sharks to study how they hunt Cape fur seals off the coast of South Africa.
South Africa's south-western coast is famous for its “flying” great whites, sharks that hunt seals with a zeal rarely seen anywhere else, by breaching out of the water to nab their prey. Past research has shown the sharks usually do their nabbing at the surface at twilight, when the seals are moving between land and sea. As you can imagine, this is pretty stressful for the seals.
Intriguingly, at the Dyer Island Marine Reserve, on the southern tip of the cape, sharks are observed close to the seal colonies throughout the day, not just twilight, but predatory surface behavior is rare. The seals here also exhibit lower levels of cortisol (stress hormones). So, why are the seals here not as stressed as those up near Seal Island?
Previous assumptions had been that the abundant kelp forests off Dyer Island provided a refuge from the sharks, which don’t enter. This had never been tested before though.
The researchers managed to tag eight sharks’ dorsal fins with cameras designed to pop off and float to the surface after a few hours, and collected the data later. The results, 28 hours of incredible footage that revealed new behaviors for the first time, have been published in Biology Letters.
The footage, amazingly, shows sharks charging through the kelp fronds, navigating tight channels, hunting for their prey. The seals, for their part, displayed predator evasion techniques, like blowing bubbles at the sharks.
“The film we collected gives us a new perspective on this species. We can see how they interact with their surroundings in real time, and they are able to make some pretty spectacular 180-degree turns in the kelp forest,” Mr Jewell said in a statement.
“In the past we would have to guess. Being able to see what these fish do in this habitat helps to bring another layer of understanding to the behavior of these ocean giants.”
Admittedly, none of the footage captured actually shows a shark catching a seal, which may support the hypothesis the kelp works in the seals’ favor. Jewell also suggests further study, perhaps on the sharks in the kelp forests off California and Australia, would need to be carried out to confirm this behavior. But every little bit we learn about these amazing creatures helps us make informed decisions to ensure their species' survival.
