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Were There Any Poisonous Dinosaurs? If So, Which Ones?

Much of what we know about dinosaurs is constructed from buried fossils, pieced together by paleontologists to give us a better understanding of these deadly creatures. In this way, dinosaur teeth fossils could be used to determine whether or not venomous dinosaurs existed. 

Evidence regarding the existence of poisonous dinosaurs is inconclusive. Venomous creatures typically have specialized teeth that allow them to inject poison and very few fossilized teeth have been found like this; The Sinornithosaurus did, but paleontologists are divided on its ability to inject venom. 

The dinosaurs that appear within mainstream media have many embellished or completely fictionalized abilities. When it comes down to whether or not any poisonous dinosaurs existed, it’s crucial to separate fact from fiction.  

Could Any Dinosaur Spit or Inject Poison? 

In the Jurassic Park franchise, the Dilophosaurus is brought back to life. However, the film recreation of this dinosaur that lived in the early Jurassic period takes many liberties for the sake of movie magic. This has led many people to believe that the Dilophosaurus could spit Poison as it did in a scene from the movie. How accurate is this representation when compared to scientific evidence? 

The Dilophosaurus, based on fossil evidence, was an estimated 23 feet long and weighed around 900 pounds. While the Dilophosaurus was indeed one of the earliest large predatory dinosaurs around, there is no scientific evidence to suggest that it could spit venom, as the movie led viewers to believe. 

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However, not only movies are to blame for this common misconception. The Komodo Dragon is perhaps the largest living lizard predator today; however, they are not directly descended from the dinosaurs. Instead, Komodo Dragons and dinosaurs share a mutual ancestor, and they both belong to the Diapsida subclass of reptiles. 

Komodo Dragons have a potentially fatal bite that can secrete enough venom to kill prey within hours. The Komodo Dragon’s teeth are serrated in a similar way to other animals that use venom to kill prey. Their teeth are used to infect prey with a toxic protein that lowers the blood pressure of the victim and sends them into shock. 

If a distant relative of the dinosaurs living today can secrete venom, were there any dinosaurs that had this ability, too? To answer this question, the television needs to be turned off, and fact needs to be separated from fiction. To find an answer to this question, one must look at what the fossilized evidence suggests about the ability of dinosaurs to poison their prey. 

Separating Fact from Fiction 

While the Dilophosaurus could not spit venom as depicted in the Jurassic Park movie, fossil evidence was located that had the potential to prove the existence of poisonous dinosaurs. These fossils belonged to the Sinornithosaurus, leading paleontologists to believe that this dinosaur could possibly poison its prey. 

The analysis of tooth remains one of the best methods of determining whether certain prehistoric creatures were venomous. The Sinornithosaurus was a small raptor that had certain elongated teeth that featured lengthwise grooves running down them. This presented possible evidence of the dinosaur being poisonous. 

This groove, which could have functioned as a canal for venom, stretched from the tooth’s root to the tip. The Sinornithosaurus’ tooth remains were reminiscent of the fangs found today in certain snake species. There was further evidence that backed up this hypothesis, such as a possible pocket for venom glands within the Sinornithosaurus’ jaw which could have functioned as part of a venom-delivery system. 

Unfortunately, this theory has been disproven numerous times in the last decade. Paleontologists found too many discrepancies in the tooth remains when compared with other poisonous creatures. Currently, there is no conclusive evidence of the prior existence of any poisonous dinosaurs – you’ll have to stick with fiction for that one. However, what did make the dinosaurs such deadly prey if they weren’t poisonous? 

Dinosaurs had Advantages Other Than Venom 

A T-Rex’s bites was deadly

Before they were dead, dinosaurs were deadly. Dinosaurs do not pose any threat to you due to their extinction and the impossibility of cloning dinosaurs the way they do in the movies. The oldest DNA found in fossilized dinosaur remains is only a million years old and would not be able to provide sufficient genomes to resurrect these long-dead creatures. This means that it is impossible to resurrect dinosaurs the way they are in the Jurassic Park franchise

However, if you were to travel back in time to the age of the dinosaurs, many dinosaurs you encounter would be formidable threats. While herbivores will not pose much threat to you in this hypothetical scenario, their carnivorous counterparts could eat you in one bite.

Try to picture yourself eating a single piece of sushi… in this scenario, you are that piece of sushi. While our size compared to that of the dinosaurs makes them naturally deadly to us, if they were still around, there are reasons they reigned when they did. 

In combat with another predator, a dinosaur would have been able to easily outfight other predators of a similar size. This is due to the anatomy of a dinosaur’s lungs. Birds today, descended from avian dinosaurs, have air sacs that allow for a constant flow of air through the lungs. This allows air to travel to both the lungs, where the exchange of gas takes place and the air sacs. This creates a cycle of air that flows continuously. 

Many dinosaurs are believed to have had such air sacs, allowing them to stay oxygenated even in battle with another foe of a similar size. This theory stems from fossilized remains that showed cavities that could have housed these air sacs. This would give dinosaurs a competitive advantage over the prehistoric animal kingdom, leading to their deadly legacy as we know it. 

The Deadliest Dinosaurs Didn’t Need Poison  

You may wonder which dinosaur was the deadliest of them all. With a name that means ‘tyrant lizard king,’ the Tyrannosaurus rex reigned supreme. While other dinosaurs may have been slightly bigger, heavier, or faster, the T-rex came out on top almost every time.

The Tyrannosaurus rex could sniff prey over many miles and, once they reached their prey, they could bring them down in one bite. The majority of other dinosaurs would need to bite their prey more than once, which is a testament to the sheer strength of the T- rex’s bite. 

In fact, the force from one bite from a T-rex is equated to three times the force of a great white shark’s bite. It is possibly the deadliest bite to ever exist, which is one detail the Jurassic Park films got correct. The Tyrannosaurus rex didn’t need to inject you with venom; it simply needed to take one bite. 


Evidence to support the existence of poisonous dinosaurs is currently inconclusive. While the research was done into tooth remains of the Sinornithosaurus to deduce whether it was used to deliver venom, paleontologists have discredited this theory.

The misconception that poisonous dinosaurs once roamed the earth is due to the Jurassic Park films. Within the franchise, the Dilophosaurus, which in fact existed millions of years ago, was given poisonous abilities. This was, however, a plot device and not based on any scientific evidence.

Given the lack of evidence about any poisonous abilities, it goes to show that dinosaurs didn’t need to inject their prey with venom to reign. They got their reputation as deadly creatures without the need for poison!

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