Remember that nail-biting kitchen scene in 'Jurassic Park'? You know the one … bloodthirsty velociraptors, terrified kids, lots of shiny stainless steel and clanging cutlery. Well, this bit of info might just ruin it for you … With no living raptors for reference, 'Jurassic Park' sound designer Gary Rydstrom was forced to search for a pseudo sound source. And he did what any good sound designer would: he recorded tortoises having sex. That’s right, the communicative grunts of the movie's velociraptors are actually the satisfied squeals of copulating reptiles. Have a listen ...

"It's somewhat embarrassing, but when the raptors bark at each other to communicate, it's a tortoise having sex," Rydstrom told Vulture in 2013.

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Muldoon’s memorable ‘death by raptor’ loses some intensity once you know that the hissing sound he hears right before his demise is that of an angry goose.

Avid 'Jurassic Park' fans are no strangers to the mash-up of animal sounds used to bring Spielberg’s dinosaurs to life. Rydstrom recorded an array of animal grunts, squawks, squeals and growls, and blended them together to produce the soundtrack we hear in the film. And as it turns out, many of the dino sounds in the movie are a little smutty in origin. The gallimimus squeal? A horse in heat. The raptor screams? A dolphin ready for action. At least the T. rex keeps it clean: "The key element of the T. rex roar is … a baby elephant," according to Rydstrom.

So what do dinosaurs really sound like? Well, we don’t actually know. Unfortunately, the anatomy that animals use to make sounds, like vocal chords and resonating throat sacs, don’t fossilise like bones do. Experts have to turn to evolutionary cousins like the crocodilian reptiles and birds to guesstimate what dinosaurs would have sounded like. Crocs and other similar reptiles use soft tissues to vocalise. They have a larynx and create noise in much the same way that humans do (albeit their vocalisations are a touch more terrifying). Birds (which are technically reptiles as well) have a structure called a syrinx that probably evolved independently. So dinos could have had one or both of these noise-making organs.

It's doubtful that raptors would have sounded like mating tortoises, but we're willing to bet this bit of cinematic trivia will pop back into your head one day. Perhaps when you're revisiting the 1993 classic on a nostalgic Saturday evening, or maybe while you’re clinging to the edge of your seat at the premiere of the new 'Jurassic World' movie, you'll think about turtles getting it on.

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A re-imagining of Timmy's kitchen experience ... image © Jurassic Park and Michael Bentley