Sharks are one of the world's most feared apex predators, and while attacks on humans are extremely rare, their ferocity shouldn't be underestimated.
Case in point, this shocking video that's emerged of two Great Whites - that's the shark from Jaws - attacking each other in a frenzy of cannibalism.
The spine-chilling footage was released as part of National Geographic WILD's Cannibal Sharks show, which looks like a must-watch for anyone whose already binged their way through Dahmer.
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However, as shocking as the rare footage is, it's worth noting that all sharks are cannibals, according to Professor Mark Meekan, of the Australian Institute for Marine Science.
"It's not just one rogue shark attacking other sharks or even one species of shark attacking other sharks, it's lots of different sharks turning on each other," he said.
That's why the footage was aired - to shed light on the increased number of reported cannibal attacks between sharks on the Gold Coast of Australia.
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The professor believes that more and more sharks are turning to cannibalism because of the deterrents used to keep swimmers safe on the coast - like nets and baited hook lines.
Once a shark ends up embroiled in these, it will automatically send out distress signals, alerting any other sharks in the area to the news that there's now an easy (and large) meal on offer.
Professor Meekan said of the photograph below: "This is an enormous shark. It's 12-feet long but look at the size of that bite, it's absolutely massive.
''That's an immense amount of power you need to take a bite out of another shark like that - you have to be pretty big yourself.
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''If I was a betting man, I might even pick another great white shark for that one. These things are apex predators for good reason."
To put the scale of shark cannibalism into context, according to Science Focus, new research has suggested that the now-extinct Megalodon sharks actually ate their siblings in the womb.
These weren't just any old babies either; they were reportedly two metres long at birth - that's bigger than Dwayne 'The Rock' Johnson.
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But this isn't the only evidence of historical shark cannibalism either.
Fossilised poo from the prehistoric orthacanthus - also extinct - showed that it had eaten baby shark teeth, which were also fossilised.
Professor Meekan said: of the find: "That shows that 300m years ago these were cannibal sharks. Shark on shark predation is a fundamental trait."
Topics: TV and Film