'Jurassic Park' turns 25: Behind-the-scenes moments you may not have known about the iconic summer thriller

The low, approaching rumble. The ripples in the water cup. The silence. Then a giant T-Rex emerges from the brush.

The cold rush of fear that washes over you during that iconic scene in “Jurassic Park” feels as real today as when the movie premiered 25 years ago.

Since the original “Jurassic Park,” the franchise has grown to include four more chapters, the latest being “Jurassic World: Fallen Kingdom,” which premieres this June.

Members of the cast and crew from the original 1993 film sat down with ABC News for the “20/20” special, “Lights, Camera, Summer,” to talk about funny and interesting behind-the-scenes moments from this summer classic.

1. There are approximately 15 minutes of dinosaur footage in the entire movie

Out of the entire “Jurassic Park” film, which runs for two hours and seven minutes, the dinosaurs only appear for approximately 15 minutes combined, according to crewmembers John Rosengrant and Matt Winston.

The movie used both animatronic dinosaurs and puppets overseen by Matt Winston’s father, the late Stan Winston. They were all part of the Stan Winston Studio team that was responsible for operating and moving the dinosaurs. Matt Winston is the co-founder of the Stan Winston School of Character Arts, an online visual effects program, and Rosengrant is the co-founder of the special effects studio Legacy Effects.

“It's taking that great philosophy of when you see it, it's amazing and you pepper it throughout the whole film, so you think you're seeing dinosaurs 24/7 but you actually don't. But when you do see them, they're top-notch and excellent,” Rosengrant said.

This technique, Matt Winston said, harkens back to director Steven Spielberg’s gifts as a filmmaker. Stan Winston’s team worked with Spielberg on a number of blockbuster films, including the first three “Jurassic Park” movies and “A.I. Artificial Intelligence.”

“In ‘Jaws’ there are very few shots of that shark and yet you're aware of the shark's presence throughout the film through music and other techniques he used, and he did that as well in ‘Jurassic Park,’” Matt Winston said. “There's a lot more dinosaur footage than there was shark footage, but still he used that technique of, ‘It's over there, I can hear it breathing but I'm not necessarily seeing it.’”

Actress Laura Dern, who played Ellie in “Jurassic Park,” described to “20/20” what it was like to see the dinosaurs up-close.

“Thanks to Stan Winston, there was a triceratops right in front of me... it just was so real,” Dern said. “It's one of the most beautiful things I've ever seen. The raptor I wasn't as comfortable with. Because of the puppetry, you felt like you were right there -- in bliss or in terror.”

2. The T-Rex was so large, the building it was housed in had to be altered

Matt Winston said Spielberg went to Stan Winston to build the dinosaurs after seeing the 14-foot-tall Alien Queen he had built for James Cameron’s 1986 film, “Aliens.” But developing the giant T-Rex for “Jurassic Park” proved to be a major challenge.

“Nothing had ever been done on this scale, specifically the T-Rex,” Winston said. “Although the other dinosaurs were incredibly impressive, to build a 40-foot long puppet had never been done before, and that's exactly the kind of job dad liked to take.”

But as Stan Winston's team started to build the T-Rex in their workshop, they realized they needed a bigger space.

“[Stan said] ‘We can raise the roof. We can also make the door bigger to get it out at the other end and... We're going to modify this building,” Rosengrant said. “You felt like you were really in the middle of something special... You're sculpting a dinosaur. Not many people in the world have done that.”

In the end, Rosengrant said the T-Rex ended up being 36-feet-long, 18-feet-tall and weighed around 12,000 pounds.

3. A team of people had to dry off the T-Rex with towels, hair dryers every day

For a movie where some of the most intense scenes are done in the rain, Winston and Rosengrant said the T-Rex was not waterproofed. There was a team of people who had to dry the dinosaur out every day after shooting.

“Lots of long nights with blow dryers and fans... drying it out, squeezing it out,” Winston said. “It was nuts ... after the shot was done, everyone would run to the T-Rex and just start mopping it off with towels.”

“It was all night,” Rosengrant added. “There was a night shift that would come in to continue the process of drying the T-Rex so he'd be ready for his next day.”

4. A devastating hurricane hit while shooting the film

About three to four weeks into shooting the original film in Hawaii, the cast and crew had to take shelter when Hurricane Iniki slammed into the island of Kauai on Sept. 11, 1992. It’s still one of the costliest and most powerful hurricanes to hit the Hawaiian Islands, according to the National Oceanic and Atmospheric Administration (NOAA).

“That experience changed everything,” Dern said. “You become a family instantly. We walked through a natural disaster together, and so we were so, so bonded. For the next several months when we were filming, we were like... ‘We went through everything' ... Given that there was a hurricane in the movie and everything was so radical on this island, it just changed the whole experience.”

5. The T-Rex lost a tooth during the kids' car scene

Actress Arianna Richards, who played young girl Lex in the original film, said Spielberg changed her character in the movie to be different than what was in Michael Crichton’s book, “Jurassic Park,” for which the movie is based.

In the book, the girl is the younger sister, but in the movie, Spielberg made her the older sibling “with all the computer knowledge to be able to save the day,” Richards said, who was 12 years old during filming.

“It was really something to have that empowerment,” she said.

One of the most dramatic scenes in the movie is when Lex and her brother Tim, played by Joe Mazzello, were trapped in the Jurassic Park SUV as the T-Rex attacks. Richards said she never felt scared or unsafe during filming, but in that scene, the T-Rex suffered a minor “injury.”

“The T-Rex got really close to us when we were filming the scene where he was crashing down on the vehicle, and at one point, the T-Rex's tooth actually hit the glass and ended up breaking off,” she said.

6. Joe Mazzello got the 'Jurassic Park' part after auditioning for 'Hook'

Mazzello got the part of Tim, the little boy in “Jurassic Park,” after he said Spielberg watched his audition for “Hook,” another beloved '90s film starring Robin Williams and Dustin Hoffman. He was 7 years old when he auditioned.

“I was a little too young for the [“Hook”] part, but Steven came up to me after that and said, ‘Don't worry, Joey, I'm going to get you in the movie this summer,’ and then he offered me ‘Jurassic Park,’” Mazzello said. “In fact, ‘Jurassic Park,’ he changed the ages of the children so that I could play Tim. Tim was originally in the book older.”

7. Spielberg had the crew sing 'happy birthday' to Mazzello after a run-in with raptor claw

While filming the heart-pounding raptor kitchen scene, Mazzello said there was one take where one of the raptors was being pushed on wheels and its metal claw hit him in the face. And it happened to be his birthday that day.

“I fall on the ground, I'm dizzy. Everybody comes over, running and Steven [Spielberg] comes over, ‘Joe, Joe, you OK? You OK?’ I'm a little like, ‘yeah, yeah. I think so,’” Mazzello said. “And he goes, ‘Well, I think this is as good of a time as any. Ready everyone? Happy Birthday to you,’ and the entire crew is singing ‘Happy Birthday’ to me while I'm on the floor, dizzy from getting hit by the claw of the raptor.”

8. Wayne Knight said he had a 'make-up problem' on 'Seinfeld' after spitting dinosaur scene

Knight had already taken on the part of Newman, the scheming mailman who was Jerry Seinfeld’s nemesis on his TV sitcom “Seinfeld,” when he landed the part of Dennis Nedry in “Jurassic Park.”

In one of the movie’s most memorable scenes, Nedry comes face-to-face with a Dilophosaurus, which extends its throat fan, screeches and spits purple slime on his face and shirt.

“One night, I went back to shoot a ‘Seinfeld’ [episode] and I came back while we were shooting ‘Jurassic [Park],' and I said, ‘You know when you did the thing with the spitter?’ They go, ‘Yeah.’ [I said] ‘It kind of dyed my face purple.’ He [dinosaur creator] goes, ‘Yeah, it'll do that,’” Knight said. “So there was a make-up problem going back to TV, we had to like cover the spot ... and they basically said, ‘Don't blink, because we'll do it again.’”