How do we know the megalodon is extinct if we explored less than 5% of the ocean?


How do we know the megalodon is extinct if we explored less than 5% of the ocean?

In: 2002

We draw conclusions from the available evidence. We’ve been wrong about extinct animals before. Science isn’t about proving things 100%, it’s about drawing the best conclusion from the best available evidence.

This explored 5% part is fairly misunderstood. All of the ocean is mapped to at least a hundred meter (edit: was going off my head, in reality several km) resolution. This 5% part refers to the parts mapped to around 30 meter resolution or better.

Now this is topographic mapping, of course humans haven’t been to personally or remotely in most of the ocean, and there’s certainly lot of the marine biosphere waiting to be discovered. But the existence of something like the megalodon could be fairly well excluded.

Most obvious being their fossils remain just stop appearing at a certain age rocks. This alone does not automatically means they went extinct then, since fossilisation is a peculiar process, there’s a whole term for creatures that just re-appear after long bouts on no records (Lazarus taxons). But nevertheless we should have found some indicators of it’s existence for an animal that large, but there’s none. Take giant squids for example: They long have been known by maritime cultures, occassionally dead specimen gets washed out to shores, we see wounds on whales caused by giant tentacles, and of course we directly observed them.

For something like the megalodon, or a plesiosaur to name another popular example, we should have seen *some* evidence of it being still around.

For an animal that large, it’s likely we’d see SOME recent remains of their teeth/carcasses. But the record of them just stopped at a certain point, with nothing recent. Also, the claim that only 5% of the ocean has been explored is a little inaccurate in this context. The ocean has been mapped out and traversed and fished and explored enough that if creatures like megalodon still existed, there almost certainly would have been an encounter.

Animals don’t simply exist. They have a role in their ecosystem. They need things and they affect things. Large predators have a massive effect on their ecosystems, their presence is clear even if you never see them.

Megalodon effectively evolved to target large prey like small whales, large turtles and similar creatures. And that leaves a mark. We have tons of evidence of megalodon’s effect on their environment, for example, whale bones with scars made by megalodon teeth.

All of that evidence simply ceases to show up after a certain point in time. Unless these sharks suddenly got really good at hiding the evidence of their existence, it’s unlikely they’re still around somewhere.

So you could say, but what if it’s hiding somewhere in the deep sea? Well, the entire ecosystem it needs to exist would also have to be hiding down there. The deep-sea is a place of extreme scarcity. The organisms adapted to exist there tend to be very slow, energy-efficient ambush predators. That’s not a place for a gigantic active hunter.

But perhaps a better indicator is how much things changed when signs of megalodon disappeared. Being too big often isn’t an advantage for prey animals, it makes them easier targets. But as soon as all signs of megalodon disappeared, its prey animals started to diversify and grow bigger.

The large whales we have today would have never thrived in a world that still had megalodon in it.

Because if an Apex predator of that size and aggressive nature was still around, one of them would have attempted to hump a nuclear submarine by now.

Because even though the megalodon was the largest shark, it wasn’t the [greatest]( Whales didn’t grow to their giant sizes until after (or because of) the megalodon died out. It died because it was outperformed by the great white shark which could do everything it could do at a fraction of the energy cost. If they did survive it would be beacuse they eat the giant modern day whales that are too big for the great whites but then we would see signs of whales being hunted in that method. We know the megalodon is extinct because we know what killed it

I saw this episode of Star Trek: Voyager. They aren’t extinct. They invented space ships and moved to the Delta Quadrant.

Someone could explore quite a large percentage of my house without physically finding me. But even if they don’t physically find me, there’ll still be signs that I’m the homeowner- photos on the wall, mail addressed to me, my clothes in the closet, a huge pack of my favorite hot dogs in the fridge, etc. I can’t think of much of my house that *doesn’t* bear some hallmark that I live there.

They aren’t finding any signs that the megalodon lives in the ocean. Even if they haven’t explored all of it, they can be confident that the 5% they’ve explored would have shown signs of something that big.

Because superpredators aren’t stealthy, footprint-wise.

A fish the size of megalodon requires a LOT of food. It would have to live somewhere that sustains large prey and/or migrate to follow whale migrations. If nothing else, we’d be able to tell from the way whale pods behaved that there was something bigger than orcas out there hunting them.