A movie about a dinosaur attraction park—what could go wrong? While the majority of people enjoyed the films for what they were, there’s no doubt that a couple of scientists were mentally checking off everything that was not scientifically sound. “Reviving ancient, fossilized DNA is not so simple!” “Nobody move a muscle? Well, they can still smell you, just so you know.” These are just a snippet of the things that Jurassic Park got totally wrong. Below are five examples.

1. Jurassic Period

The entire franchise was named after the Jurassic Period which had the brachiosaurus, diplodocus, plesiosaurus and stegosaurus, just to name a few. The T-Rex didn’t come into play until the Cretaceous period, which took place some 66-68 million years ago. Though, you can’t fault the filmmakers—Jurassic Park sounds way cooler than the Cretaceous Park. Besides, what’s the point of a dinosaur movie without including the most popular and most formidable of all the dinosaurs that ever graced the Earth?

2. Sense of Smell

One of the most iconic lines both in Jurassic Park and Jurassic World is “Nobody moves a muscle,” when the gang encounters a T-rex. This implies that the T-rex relies on its eyesight to spot their prey and if they so much as shifted, even just a little, then they’d become that T-rex’s next meal. In reality, the T-rex would have used more than its eyesight to spot prey. Like most animals, they would have been most dependent on the sense of smell. And considering that they were running around the majority of the film, that T-rex would have had no problem sensing them.

3. Dinosaurs’ IQs

Remember that scene in Jurassic World with that one really intelligent raptor named Blue, who not only followed orders with ease, but also showed compassion and empathy by switching sides and protecting Chris Pratt’s character and the rest of the characters? Well, the truth is that dinosaurs may have been huge but their brains didn’t match their size. And given how small it was, a dinosaur would have been way less intelligent than they were portrayed to be—even modern-day birds have the upper-hand when it comes to intelligence. Not only that, but training them would have been next to impossible!

4. Venomous Dinosaur

In the first Jurassic film, there’s this scene where a computer programmer named Dennis Nedry is sprayed by a dilophosaurus with what appeared to be venomous saliva as he sought to escape with its stolen dinosaur embryos. The issue is that the real life dilophosaurus did not spit venom, nor did it have ear frills as depicted in the film. Also, they were much larger than portrayed in the film, measuring 6 meters or 20 feet long and weighing over 450 kilograms or 1,000 pounds. In fact, curator Scott D. Sampson published an article by Scientific American explaining that there is little to no evidence that venomous dinosaurs ever existed.

5. DNA Extraction

Just so you know, the idea of extracting fossilized DNA to recreate or clone a species is not that far-fetched in our modern world. But does this mean that it can actually be done? The answer is a resounding no! First of all, when you clone something, you are actually making an exact genetic copy. This includes every gene and every DNA strand. But according to a Murdoch University researcher, Mike Brunce, “All DNA would be completely destroyed in bone after about 6.8 million years. Long story short, there isn’t enough DNA present in fossils to create a clone.