When you ask someone for their biggest fear, the answer usually involves some sort of terrifying animal, such as sharks, spiders, or, in my case, slugs.
It's perhaps only the former that's capable of killing a human unless you find yourself on the end of a poisonous spider bite, and given that Jaws remains one of the most popular films of all time, it's easy to see why people aren't too keen on straying too far from the beach.
Although they can still be killing machines, the largest Great Whites these days measure around 13 feet, and we've even got a tracker that tells us roughly where the huge male species can be found.
So, spare a thought for the poor creatures who lived alongside megalodons around 23 million years ago. A new study has revealed just how massive the giant mackerel shark would have been, and frankly, it makes the sharks of today look minuscule.
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A new study conducted by scientists at Goethe University in Frankfurt suggests that the prehistoric beasts could have grown as big as 80 feet long and likely needed 100,000 calories daily to survive.
To find this out, the scientists measured the amount of zinc present in their fossilised teeth. The tissue of fish that consumed other fish was significantly less, leading them to absorb even less.
Before any of you fitness influencers think this is worth trying, the megalodon likely ate whales and smaller sharks to maintain this hefty diet, so it's probably impossible for humans.
The study also found that the megalodon's teeth were likely as big as human hands, so you certainly wouldn't want to get caught anywhere near its mouth, given that its bite had the force of an 'industrial hydraulic press'.
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Dr McCormack said: "Since we don't know how the ratio of the two zinc isotopes at the bottom of the food pyramid was at that time, we compared the teeth of various prehistoric and extant shark species with each other and with other animal species.
"This enabled us to gain an impression of predator-prey relationships 18 million years ago."
Recognised as the largest predatory fish that ever lived, the megalodon most likely weighed twice as much as a modern lorry and was also far longer, so it's perhaps no surprise it was at the top of the food chain.
Dr McCormack said: "Sea bream, which fed on mussels, snails and crustaceans, formed the lowest level of the food chain we studied. Smaller shark species, such as requiem sharks and ancestors of today's cetaceans, dolphins and whales, were next.
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"Larger sharks such as sand tiger sharks were further up the food pyramid, and at the top were giant sharks like Araloselachus cuspidatus and the Otodus sharks, which include megalodon.
"Megalodon was by all means flexible enough to feed on marine mammals and large fish, from the top of the food pyramid as well as lower levels – depending on availability."
James Moorhouse