In Jurassic World: Fallen Kingdom, humans are faced with a moral dilemma: Do we save the dinosaurs brought back to life by science when they are threatened by volcanic annihilation? Or do we let the dangerous beasts perish again?

This made us wonder whether dinosaurs really could be resurrected, and if so, what would happen if we suddenly had to share the planet with these ancient animals. Here's what science has to say.

Dino DNA

In the Jurassic Park movies, scientists extract dinosaur DNA from mosquitoes trapped in amber. In the real world, paleontologists have found huge numbers of insects and other invertebrates in amber, including blood-sucking ticks from the Cretaceous period.

Dinosaurs 101 Over a thousand dinosaur species once roamed the Earth. Learn which ones were the largest and the smallest, what dinosaurs ate and how they behaved, as well as surprising facts about their extinction.

But science has actually gone one better than fiction since the first Jurassic Park film came out in 1993: In late 2016, paleontologists announced the discovery of most of a dinosaur tail in amber, with well-preserved feathers and skin.

But even with fossilized bits of dinosaur in amber and other excellently preserved dinosaurs that retain traces of their original organic material, the chances of finding intact dinosaur DNA remains, sadly, almost nonexistent.

The nonavian dinosaurs were killed off when an asteroid or comet struck Earth 66 million years ago, and so far, it seems DNA hasn’t been preserved for long enough to be viable.

“The oldest DNA in the fossil record is only about a million years old, so it's not possible for us to reconstruct dinosaurs from their DNA like they did in the Jurassic Park movies,” says Susie Maidment, a paleontologist at the Natural History Museum in London, U.K.

However, she says, “there is increasing evidence that proteins and other soft tissues can preserve over geological timescales, so I think it would be unwise to say that we will definitely never be able to get DNA from dinosaur fossils.”

And for the past 25 years, since Jurassic Park hit cinemas, paleontologists across the world have been searching for fossilized dinosaur DNA, says Steve Brusatte, a National Geographic Explorer and author of The Rise and Fall of the Dinosaurs.

“We know that it would make our career if we were the first people to find it. But despite all the effort, nobody has ever found even a single fragment of dinosaur DNA, much less the complete or near-complete genomes that would be necessary to clone a dinosaur,” he says.

“DNA breaks down really fast, and even in a hundred years, it has broken up into tiny nonsense fragments,” says Mike Benton, a paleontologist at the University of Bristol in the U.K. “It takes massive technical power to link these bits together. So, until someone finds some dino DNA, we haven’t even got off the starting blocks.”

Life Finds a Way

Several U.S. teams are trying very hard right now to use gene editing technology and ancient DNA sequences to resurrect lost species. Bringing back animals that became extinct even 20 years ago is a challenge that is beyond us for now, Benton says.

However, gene editing technology using a technique called CRISPR is advancing at lightning speed. Already scientists have been able to stitch together genetic pieces from various animals, as the fictional teams do in the Jurassic Park films.

In the first movie, geneticists use frog DNA to fill in the missing pieces in the dinosaur DNA found in amber. In a similar real-world case, researchers led by geneticist George Church at Harvard University are attempting to insert mammoth genes recovered from ancient DNA into the modern Asian elephant genome as part of their mammoth de-extinction project.

“I’m hesitant to say it’s impossible,” Victoria Arbour, an expert on armored dinosaurs at the Royal Ontario Museum in Toronto, Canada, says of dino de-extinction. “So many scientific disciplines are making incredible breakthroughs all the time that something that’s hard to imagine now, like resurrecting a dinosaur, might be possible 25, 50, 100 years from now.”

And if we ever get past the hurdle of re-engineering an entire extinct genome to bring a dinosaur back from the dead, adding in specific interesting traits to create a designer species like the new movie’s fictional Indoraptor is going to be a relative piece of cake.

Don't Eat the Tourists

So, assuming we have created and genetically perfected our modern-day dinosaurs using technologies that don’t yet exist, could they survive and thrive alongside people?

Based on our modern relationships with large carnivores such as lions, wolves, and bears, it’s clear that people and predators rarely get along. And in most cases, people prevail while the animals dwindle.

Arbour says she’d love to live in a world where Ankylosaurus are roaming around in the wild, but it’s hard even for large plant-eating animals to coexist with humans, as we use up enormous amounts of space for growing food and building our homes and settlements.

“We don’t like large animals to encroach on those spaces,” she says. “I can’t imagine we’d coexist with a colossal predator like Tyrannosaurus rex. We couldn’t tolerate wolves in most of North America and did a pretty good job of nearly wiping them out completely—how could we live with a predator more than 70 times larger than a wolf?”

In addition, dinosaurs lived in ecosystems that have no modern analogues, Maidment says. Grass and grasslands hadn’t even evolved in the Cretaceous, and large mammals had yet to make their entrance.

“What would dinosaurs eat, and how would their digestive systems cope? How would they deal with mammalian predators? Where would we keep them? And what rights would they have? I think the ethical issues around cloning a dinosaur would be almost as difficult as the scientific ones,” she says.

“The dinosaurs would be aliens in our world,” agrees Brusatte. “They evolved tens or hundreds of millions of years ago, when Earth was much different. The continents were in different places, the atmosphere was different, the plants were different. Maybe they couldn't cope at all.”

Welcome to Jurassic World

But, Brusatte says, we should remember a simple but powerful truth: Dinosaurs already coexist with us in the form of birds. Today’s avian animals are the descendants of primitive ground-dwelling birds that survived when all the world’s forests were destroyed 66 million years ago.

Are Birds Modern-Day Dinosaurs? Modern birds consist of 247 families and 10,731 species, more than any other vertebrate group except fish. An asteroid strike 66 million years ago devastated the dinosaurs. But today’s birds are proof there were a few survivors.

“Turkeys, ostriches, and eagles are not really that different in their looks or behaviors than extinct dinosaurs such as Velociraptor. So obviously humans and dinosaurs can live together,” notes Brusatte. “We keep dinosaurs as pets, eat them, enjoy looking at them in nature and in zoos, and treat them as mascots for some of our favorite sports teams.”

Arbour says that while she loves the ongoing research into resurrecting extinct species, she hopes that our focus will remain on conserving the species that are still here.

“The wonder we feel when we look at dinosaur fossils in museums,” she says, “can help inspire us to appreciate the finality of extinction and encourage us to protect the species that share our planet with us today.”