The rise of human beings from wussy tree-dwelling primate to conquerors of planet Earth was largely due to luck. We evolved during a time when most truly horrifying predators existed only as fossils, which means we could do things like walk around on the ground, swim in the ocean, and live past the age of 19.

Which does sort of make you wonder, what would become of the human race and the modern world we live in if suddenly some higher power just resurrected all of pre-history’s most terrifying creatures? Would we still have beach vacations? Camping trips? Ranching? Survival in general?

Thankfully, the era of enormous, terrifying predators is mostly over, with the exception of grizzly bears, crocodiles, and the Discovery Channel. But because it’s fun to look back through time and ask ourselves "What if?" let’s have a look at some of those horrifying, real-life creatures of bygone eras that would almost certainly wreck the modern world if they somehow managed to make it to the 21st century.

A huge marine reptile that could eat your sailboat

Kronosaurus fossil

If your mom forced you to watch Jaws as an 8-year-old ("It’s a classic!") and then you couldn’t sleep for days because you were convinced Jaws was living in your waterbed, then you almost certainly don’t want to hear about Kronosaurus because Kronosaurus is a million times scarier than a great white shark and would make pretty short work of both you and your waterbed.

According to ThoughtCo, Kronosaurus was named after Kronos, the Greek Titan who ate his own children, so yeah. Kronosaurus was a marine reptile that lived 120 million years ago, measured roughly 33 feet from snout to tail, and weighed maybe 7 to 10 tons. By comparison, the largest-known great white shark is about 20 feet long and weighs at least 2 tons. Kronosaurus’ teeth weren’t as sharp as a great white’s, but what it lacked in slash-worthiness it made up for in brawn and speed. It was a seriously fast hunter and probably killed by crushing and shaking its prey.

So what would it mean for modern humans if this terrifying creature suddenly reappeared in oceans around the world? Well, it could probably eat your 15-foot sailboat, and it would certainly not hesitate to eat a 7-foot surfboard or a 6-foot swimmer. So say goodbye to oceanic recreation unless it’s on a really, really big boat, and even then you might want to get your insurance policy in order well in advance of your bon voyage.

A dragon. Just kidding but this creature might as well have been.

Argentavis magnificens

The F-104 Starfighter has a wingspan of just under 22 feet. So did the Argentavis magnificens, but one of those things is not like the other. The F-104 Starfighter is an airplane, and the Argentavis magnificens was a bird. That’s right, a bird that was literally the size of a freaking airplane. So if this creature existed today you would probably just not want to go outside, ever.

According to Ameghiniana, Argentavis magnificens lived in Argentina roughly 6 million years ago. It was a vulture, but it didn’t eat just carrion. Scientists think it also consumed prey, like large rodents, small armadillos, and camels. Yes, camels. Granted, the camels of 6 million years ago were only the size of large deer, and Argentavis were probably only feeding on young camels but still, daaang. If this thing were alive today it would seriously change the goat farming industry, that’s for sure.

But Argentavis magnificens was not actually the largest bird that ever lived (that we know of). That honor belongs to Pelagornis sandersi, which had a whopping 24-foot wingspan. Scientists think Pelagornis sandersi probably preyed on things like fish and squid, so it probably wouldn’t go for a person but still, imagine what it would be like to get crapped on by one of those things while you were whale-watching. It might not wreck the world or anything, but it would sure wreck your day.

This creature was a real-life demogorgon


If the demogorgon of Stranger Things haunts your nightmares, consider this: The gorgonops (Greek for "dreadful face"), which shares a similar sort of name and a similar sort of reputation and at one point actually existed.

According to Prehistoric Wildlife, this thing could reach roughly 10 feet in length, depending on the species. It was not a reptile but it was not a mammal, either — it was a primitive therapsid, which was an ancestor of today’s mammals except without being fluffy or cute in any way. It had huge canine teeth like a sabre-toothed cat and was one of Africa’s key predators during the Permian.

The gorgonops might have been warm-blooded and was probably fast on its feet, and its enormous canines would have been well-equipped to tear through the thick hides of most of the herbivores that lived at the time, and also your leather jacket, Ultrex coat, or your super wussy paper-thin human skin. So how would this creature change our world if it still lived today? Well, it probably would have eaten you by now.

A snake that could eat you and the horse you rode in on


Who doesn’t love snakes? They’re so cuddly and huggable and venomous and too small to constrict you to death and actually eat you or anything, with a few horrifying exceptions. The largest snake alive today is the giant anaconda, which grows to about 17 feet and can weigh around 550 pounds. (Some anacondas have been noted at around 30 feet in length, but let’s just bury that little tidbit as deep as it will go, hmm?)

As horrifying as the idea of a 550-pound snake is, it’s only about 22 percent as horrifying as a 2,500-pound snake. Now, at 42 feet, titanoboa was only marginally longer than the longest living anaconda, but it was nearly a ton heavier which means it was more like a horrifying, horrifying, horrifying worm than a snake, except for the whole constricting you until you die thing that worms don’t tend to do. According to Smithsonian, if you stood next to one of these things it would come up to your waist, at least temporarily because then it would be eating you and you’d no longer be, you know, standing.

So let’s imagine what life would be like if this creature were roaming the suburbs. We wouldn’t have cats anymore, or dogs, or horses … or probably circus elephants either. On the flip side, we wouldn’t have to worry about bears in our campsites because the titanoboa would eat all the bears.

The Monster Shark doesn’t actually live, no matter how badly Discovery wants it to

Megalodon jaws

Kronosaurus was terrifying but there was another sea creature that could have taken Kronosaurus with one fin tied behind its back and that, of course, was megalodon, which you might know from such fake Discovery Channel documentaries as Megalodon: The Monster Shark Lives. We don’t have to tell you all the many ways that megalodon, if it still existed, would wreck the world. It would eat seals and walruses and it would laugh in the face of dolphins and then eat them, and then it would eat boats and lighthouses and airplanes and whatever the hell else it wanted to eat. Also, Discovery Channel would have been telling the truth and therefore would become quality television programming, and that’s really getting into some bizarro-world stuff right there.

Megalodon roamed the seas from 23 million years ago to about 2.6 million years ago, and since Kronosaurus lived 100 million years before the earliest evidence of megalodon, we’ll sadly never find out who would win in a fight. Odds are it would be megalodon, though. According to LiveScience, megalodon might have been 60 feet long or it might have been as much as 80 feet long, though some party-poopers seem to think that the megalodon wasn’t actually any bigger than Kronosaurus, which would be boring. Still, a 33-foot shark is 11 feet larger than the largest known great white, so yeah, it could still wreck some stuff.

This animal would flip office culture on its head

Terror bird

So imagine if a T. rex had a baby with a chicken and then an ostrich had a baby with one of those ginormous Steller’s sea eagles and then the two babies grew up and met each other on Tinder and then their offspring decided to turn the entire world and all its creatures into a Las Vegas buffet. That was Phorusrhacidae, which are much more accurately known as "terror birds." According to the BBC, these flightless birds were basically just feathered, beaked velociraptors only without the charm and good looks. The terror bird became South America’s top predator and reigned for nearly 60 million years, finally disappearing from the fossil record around the same time as megalodon.

One of the largest of these nightmarish creatures was Titanis, which was nearly 10 feet tall, had a top speed of around 43 mph (similar to an ostrich), and could snap the leg of a cow with its enormous feet and could also peck your head off. Literally. So if these things still roamed the Earth, well, there would be a ton of cows with broken legs and lots of humans missing their heads. In the plus column, most employers would be totally fine with telecommuting because no one would want to leave their house, ever.

This creature probably wouldn’t eat you or anything but still, daaang


Crocodiles are one of the few creatures that actually eat human beings. We may think wolves and tigers and lions are scary, man-eating beasts but when was the last time you heard about someone actually getting eaten by one of those? The saltwater crocodile is the largest reptile on earth — it can grow to be 23 feet long and can weigh more than a ton. Thanks, Nature, that’s big enough. No, really.

Well at one point, Nature evidently disagreed and decided to make a much, much bigger crocodile because a 1-ton, 23-foot killing machine is evidently just not impressive enough. Enter Sarcosuchus, the world’s largest known crocodile. According to ThoughtCo, Sarcosuchus, also known as "SuperCroc" (because of course SuperCroc) could reach lengths of 40 feet and might have weighed 10 times as much as its pathetic little saltwater cousin.

Now, scientists do think that Sarcosuchus probably ate fish, which means it probably would not have really been a huge threat to humans but still, you probably would want to avoid building a theme park right next to the swamp where it spends most of its time. And as far as fishing is concerned, well, the industry might not have the same kind of draw if these things were competing with anglers for all the rainbow trout in the local river.

This beast would seriously mess up the Bigfoot industry


Bigfoot is so elusive he evidently doesn’t poop and disintegrates when he dies, and occasionally puts bear DNA in his hair samples just to confuse everyone who wastes their time and money looking for him. And if you don’t find him, you can buy plenty of T-shirts and coffee mugs and fridge magnets that will at least let your friends know you gave it your best shot.

So what would the Bigfoot industry look like today if Gigantopithecus still roamed the Earth? According to National Geographic, this huge primate was 10 feet tall and weighed more than half a ton. It thrived in the warm tropical forests of China for around 6 to 9 million years, then the last Pleistocene ice age rolled around and Gigantopithecus died out because as the climate changed and forests gave way to savannas, there wasn’t enough food to maintain a large population of calorie-hungry beasts of gigantic proportions.

Fortunately, Gigantopithecus did the smart thing — it caught a boat to southern Oregon and set up camp in the woods where it learned to emulate the haunting yet melodic call of the reality television producer. Just kidding. It did no such thing and neither did any other primate, except for humans attending the Oregon Shakespeare festival.

You’d want at least 1,000 miles of prairie between yourself and this creature


The good news is that a lot of these insanely terrifying predators lived in the ocean. So as long as you moved to Kansas or something, you’d only have to worry about decapitation by pecking, being swallowed by a snake with the girth of a large tree, baseball-sized bird poops, and random other land-based terrors. Meanwhile, the ocean could stay mercifully on the other side of the prairie. And a good thing, too, because Dunkleosteus lived in the ocean and Dunkleosteus made piranhas look like goldfish.

Dunkleosteus predates the megalodon and it even predates dinosaurs — it lived 360 million years ago, was nearly 20 feet long, and was basically the Kraken minus the tentacles plus the armor of a tank. According to Earth Touch, Dunkleosteus’ head was covered with thick, bony plates, which ended in super-sharp fangs that were made from the same material as the bony plates. They were designed to scrape together when the fish opened and closed its jaws, so being approached by one of these things was the equivalent of being approached by a dude in a helmet and plate armor who is meticulously and deliberately sharpening two large machetes, only underwater.

So in a world where Dunkleosteus still lived, swimming, boating, wading, or looking at the ocean without a sense of foreboding would all be pretty much off the table.

This animal probably did kill people

Haast's Eagle

It’s at least some small comfort that most of these creatures never shared the Earth with human beings — they vanished long before human beings took those tentative first steps out of Africa. And a good thing, too, because if all these terrifying creatures had been roaming the African landscape, the ancestors of human beings would have never come down from the trees.

Don’t relax just yet, though, because at least one perfectly-capable-of-eating-humans creature did share the world with people, and it wasn’t really that long ago, either. The Haast’s eagle lived in New Zealand and was still flying around being terrifying as recently as 500 or 600 years ago. According to New Zealand Birds Online, Haast’s eagle had a wingspan of nearly 10 feet and an arrangement of feet and claws that rivaled a modern tiger. It probably ate Moa, which were large, flightless birds that became extinct around the same time as the Haast’s eagle did.

Here’s where it gets extra-super-scary — native New Zealanders have an oral tradition that includes descriptions of Haast’s eagles actually attacking human children, so we don’t have to even imagine all the ways this predator might have been dangerous to people because it was actually, literally dangerous to people.

This creature probably also ate people

Short-faced bear

Bear spray costs like $40 a bottle, and people will pay that much for the stuff because bears are super terrifying and will actually kill and eat you if you happen to be in the wrong place at the wrong time. But hey, at least grizzly bears are typically only between 5 and 8 feet tall when standing upright, so you might actually have a chance if you decide to engage in hand-to-paw combat with one. (Haha no.)

If you ever met a short-faced bear, though, forget it. According to Bears of the World, the short-faced bear was 12 feet tall when standing upright and could weigh up to a ton. An adult was capable of killing a bison, which is like five or ten times heavier than you are and also way, way faster than you, too.

And like the Haast’s eagle, the short-faced bear shared its territory with humans, so it was almost certainly a major existential threat to the early people of North America. It died out roughly 12,000 years ago, though, which is unfortunate from a species diversity perspective but pretty danged fortunate from the camping industry’s perspective because if short-faced bears still roamed North America they’d have to make tents out of steel and that would be super impractical for most backpackers.

What about Neanderthals?


No matter how hard we try, human beings still haven’t been able to snuff out racism. So what would life on planet Earth be like if we also had species-ism to deal with? What if Neanderthals still roamed the Earth. Would we be ignoring their job applications, calling the cops on them for barbecuing in the park, and generally making life for them uncomfortable and dangerous?

Well, if Homo sapiens can’t learn to get along with each other, it seems pretty unlikely that they could learn to get along with other types of humans. On the other hand, perhaps the presence of similar but fundamentally different types of humans would be humbling. Maybe we wouldn’t have grown to think of ourselves as a completely unique and superior species, and maybe as a result of that we’d be much better caretakers of our planet.

According to Real Clear Science, Neanderthals disappeared 30,000 years ago, so we won’t ever know what our relationship with our close cousins was actually like — which makes it hard to speculate about what it might be like if Neanderthals still lived. It is a pretty safe bet, though, that Neanderthals would wreck life as we know it … but let’s just pretend that it wouldn’t be in a bad way.