The trailer for Jurassic World, the fourth installment of the Jurassic Park series, premiered one week ago today. In that time, it’s garnered more than 38 million views on YouTube, and 99 percent of Rotten Tomatoes users said they want to see the movie, out in June. The trailer’s got a Mosasaurus treating a great white shark like an anchovy, Velociraptors running alongside a motorcycle and talk of a genetically modified hybrid dinosaur that scientists “cooked up in that lab.”

As fantastical as the Jurassic Park movies are, there’s a real scientist behind the franchise – Jack Horner, a paleontologist at Museum of the Rockies, who not only served as scientific adviser on all four films, but also helped inspire the character of Dr. Alan Grant, played by actor Sam Neill. We spoke with Horner, 68, about making dinosaurs from mosquitoes and what to expect from Jurassic World.

When did you first hear from Steven Spielberg about helping with Jurassic Park?

Michael Crichton had made a character in his book that was a guy from Montana that studied dinosaur behavior [like Horner], and so Steven took that character and made more of a character like myself and then called me up one day and asked if I wanted to work as a scientific adviser on the movie…I certainly knew who Steven Spielberg was and I don’t really read fictional books, but a friend of mine, one of my colleagues had called me and told me that my character was in a book on dinosaurs. And I told her the first question I had was whether I was eaten in the book. She said no, and I said, “Alright, that sounds ok.” When Steven asked whether I would work on the movie, I said, “As long as I don’t get eaten, that will be just fine."

So Crichton based Dr. Alan Grant on you?

I think he had sort of mashed together Bob Bakker and myself. He had read and acknowledged reading Bob Bakker’s book, Dinosaur Renaissance, and my book, Digging Dinosaurs, and so he had mashed the characters together. And then Steven came and sort of took my character aside and made the Alan Grant character.

How similar are you to Dr. Grant?

Steven had me hang out with Sam Neill for a few days, meet his family, so Sam would have some idea of what a paleontologist was like…When [Grant] is standing on the hill and looking out over the groups of dinosaurs in the distance at the beginning of Jurassic Park and he says, “They really do move in herds,” that was what I worked on, the social behavior of dinosaurs.

What did you do as scientific adviser?

My job really was to work alongside Steven and answer his questions for him [and] to confirm with the computer graphics people…My job was to make sure that [the dinosaurs] looked accurate and that the movements that we’re sure of, that they would be accurate. Basically I was there to make sure that sixth graders didn’t send him nasty letters about something being wrong.

And did Spielberg get anything wrong?

There were a lot of things wrong, but it was a fictional movie. It’s not a documentary. And so I was just as happy with having some fiction thrown in there as anyone else was. I wanted it to be a good movie and so there were times that Steven and I would argue about things, but he was right. Basically, if I could demonstrate that something was true or not true, then he would go with that, but if I had some question about it and we didn’t really have much evidence about it, he would go with whatever he thought would make the best movie.

So can scientists really extract “Dino DNA” from petrified mosquitoes?

That’s not accurate at all. We have tried for years to get DNA out of a dinosaur and out of a mosquito and out of amber, and tried to get the DNA out of the amber itself, and haven’t had any luck yet. DNA is a huge molecule and it doesn’t hang together very well, so it comes apart. And as far as we know, to date we certainly have no DNA from a million years ago. We have some parts and pieces from 10,000 years ago, a woolly mammoth. My colleague, Mary Schweitzer, she has tried many times to identify or even find little bits and pieces of [DNA from] a dinosaur, and we have not been successful.

You worked on Jurassic World, so let’s discuss the trailer. What’s eating that great white shark at the beginning?

It’s technically not a dinosaur. It’s a marine reptile. It’s called a mosasaurus and the size of this one is a little out of proportion, but we don’t know the ultimate size of any extinct animal.

The line, “We have learned more in the past decade from genetics, than a century of digging up bones” – is that true?

That’s true. Now that we know that birds and dinosaurs are related, that birds really are dinosaurs, we have their genetics…We’re finding new specimens all over the world, we’re finding new associations of them all over the world, new nesting grounds. There are more paleontologists working right now, probably than there have ever been total together before.

What about “genetically modified hybrid” dinosaurs? Will those exist any time soon?

It’s just genetic engineering and we do genetic engineering all the time. We just haven’t genetically engineered a genuine dinosaur yet, but we know how to do it.

Is it safe to canoe alongside dinosaurs, like they do at Jurassic World?

I don’t see why not…If you have plant-eating dinosaurs, there’s no reason you couldn’t. They’re going to act just like modern animals we have today. It would be like hanging around a bunch of cows.

So if we had the ability to bring back the dinosaurs, should we?

In the movies, animals want to just eat people, and they can be vengeful. But in real life, they’re not.

Can you give any hints about what to expect from the new movie?

It’s going to be a good one. And the made-up dinosaur is going to be very scary.

Jack Horner is curator of paleontology at the Museum of the Rockies in Bozeman, Montana, a Smithsonian Affiliate. A T-Rex from that museum will be on view when the renovated fossil wing opens at the National Museum of Natural History in 2019. A new dinosaur exhibition, “The Last American Dinosaurs” opened at the Natural History Museum last week.