It’s one of the most famous scenes from any movie, let alone Jurassic Park: Two raptors enter the kitchen, stalking two children - their human prey.

But as the raptors make their screeches and calls, you might be surprised to know these sounds actually come from tortoises having sex.

It turns out that many of the dinosaur sounds in the hit 1993 film were made by recording modern animals - including, bizarrely, tortoises mating.

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The sound designer for the 1993 firm has revealed some secrets of Jurassic Park - and it turns out the velociraptor's 'barking' noise (kitchen scene shown) was made by tortoises having sex. Other dinosaur sounds were 'voiced' by a variety of animals. These include horses, donkeys, cattle and a dog for the T-Rex

In an interview for SF Gate, sound designer for the movie Gary Rydstrom confirmed the odd choice of sound effect.

TORTOISES ARE SMARTER THAN YOU THINK In August last year, researchers trained four red-footed tortoises to use a touchscreen in return for strawberries and other treats. The animals were able to identify between red triangles and blue dots on the display, and even learnt which side of the screen to press. The animals also were able to transfer this knowledge to a real-life, offline experiment. Professor Anna Wilkinson from the University of Lincoln led the study, alongside researchers from the University of Vienna. Advertisement

‘Yes, it’s a mating tortoise,’ when asked about the sounds they make.

Specifically, he says the ‘bark’ when one velociraptor first comes in the kitchen was created by recording a tortoise successfully mate with another at Marine World.

‘It’s riding on the back of the female tortoise. So it’s climbing up her shell basically, and then it falls off. It’s a little sexual,’ he said.

This confirms what was reported by Vulture back in 2013, that tortoise sounds were behind the noise of the raptors.

But this wasn’t the only bizarre animal noise used in the movie; it turns out horses, donkeys and even cattle were used for some of the other dinosaur calls.

‘The brachiosaur’s singing is one of my favourite sounds in the movie because it’s beautiful, but like all good sound design it's made from a non-beautiful source, which is donkeys,’ Mr Rydstrom told Vulture.

In an interview for SF Gate, sound designer for the movie Gary Rydstrom confirmed the odd choice of sound effect. ‘Yes, it’s a mating tortoise,’ when asked about the sounds they make. Shown is a stock image of Seychelles giant tortoises (Dipsochelys hololissa) mating

And even the T-Rex got the animal treatment, with Mr Rydstrom’s own pet Jack Russell terrier being used to voice the huge dinosaur.

The fourth Jurrassic Park film - called Jurassic World and starring Chris Pratt - is scheduled to be released on 12 June 2015.

And a trailer confirmed velociraptors would be making a return in the film - but whether they will similarly be voiced by mating tortoises you’ll have to wait and see whether similar sound effects have been used.