In all fairness to dinosaurs, there is nothing to fear from them. They are all dead. Unless you count the birds they have evolved into, you simply aren’t going to have a run-in with a T-Rex unless it’s at a museum. That being said, there are hundreds of species of dinosaur that are absolutely terrifying in appearance—of which we’d be afraid to run into. Jagged rows of teeth, powerful armored tails, and their sheer size make a fear of dinosaurs a healthy proposition.
Some of the scariest dinosaurs are those that preferred to eat meat, so you won’t find any herbivores on this list. That isn’t to say a colossal animal who preferred to eat leaves wasn’t something you should fear; a Brontosaurus could step on a person and probably not even know it. When it comes to fearing a scary dinosaur species, it’s all about thinking one is chasing you.
Size: 43 feet (13 meters) in length and weighing in at around 15.2 tons
When They Lived: Late Cretaceous, 98 to 97 MYA
Distinguishing Features: When it comes to a distinguishing feature, the Gigantosaurus’ size is what separates it from most other theropod dinosaurs.
Why You Should Be Scared: Gigantosaurus was one of the largest known terrestrial carnivores. Were you to somehow wake up in the late Cretaceous period and stumble upon one, it might decide to swoop down and bite you in half, which it could easily do. Some specimens have indicated they could grow much larger than the infamous T-Rex, but their size alone wasn’t their biggest concern to its prey; it was fast. It is believed to have been able to run up to 31 mph (50 km/h) making it a tough animal to run away from… for very long.
Size: Around 40 feet (12.3 meters) in length weighing in ar around 9-10 tons.
When They Lived: Late Cretaceous, 68 – 66 MYA.
Distinguishing Features: Their size, jaws, and funny little arms are their most recognizable features. Most people know of their terrifying teeth, but few realize they were probably covered with feathers.
Why You Should Be Scared: The T-Rex is probably the most infamous of all theropod dinosaurs whose suffix literally translates into “King”. Thanks to a number of films to include the entries in the Jurassic Park franchise, many people have a healthy fear of these large carnivores. T-Rex’s were likely very fast for their size and were very strong and powerful animals.
Size: These were the largest of these types of dinosaurs having, achieved a size of up to 19 feet (8.7 meters) in length.
When They Lived: Early Cretaceous, 126 MYA.
Distinguishing Features: They were likely covered with a down-like feather with some larger plumage along their heads and appendages. Their most distinctive feature was their enlarged claw on each foot. These could reach a length of up to 9.4″ (24 cm).
Why You Should Be Scared: If you watched Jurassic Park and insisted the creature called the Velociraptor didn’t really live up to its ancient inspiration, that’s because it mostly resembled the Utahraptor. They were likely very fast and may have hunted in packs, making them deadly to animals far larger than a single individual.
Size: 41 feet (12.6 meters) in length with an estimated weight of around 3.1 tons
When They Lived: Cenomanian-Turonian ~97 to 93.5 MYA
Distinguishing Features: Mapusaurus shares many similar features with other theropods. They have small, vestigial forelimbs with strong and lean hind legs.
Why You Should Be Scared: Their heads are large enough to swallow any lost time-traveler whole should they decide to give one a try. The Mapusaurus was certainly strong and capable for its size, but you would only ever run into one if you were visiting a prehistoric Argentina and possibly Chile.
Size: 24.6 to 29.5 feet (7.5 to 9 meters).
When They Lived: Late Cretaceous (Lower Maastrichtian) about 7.2 to 69.9 MYA.
Distinguishing Features: Like many theropod dinosaurs, they possessed small, vestigial forelimbs. There have been no hint of feathers in any located fossils.
Why You Should Be Scared: Hop into the TARDIS and stumble upon one of these guys and it will probably be the last thing you do. These large predators’ name, Carnotaurus translates into “meat-eating bull” and while we don’t have any live examples to check out, we can only assume those sharp, pointy teeth weren’t meant for chewing on grass.
Size: 28 feet (8.5 meters) in length, though some fragmentary remains suggest it could achieve a size of up to 39 feet (12 meters).
When They Lived: Late Jurassic, 155 to 150 MYA.
Distinguishing Features: The Allosaurus looks strikingly similar to many of the theropod dinosaurs on this list, but possessed large, bony protruding fins atop its head. It’s forelimbs were likely very useful in tearing up prey unlike many theropod dinosaurs that evolved in subsequent epochs.
Why You Should Be Scared: The Allosaurus was an apex predator who could pretty much dominate any fight it found itself in. A human would be of absolutely little to no consequence to it, but if it decided it wanted to taste one, it would be difficult to stop. You would probably have a very difficult time outrunning one as well, but laying down and playing dead might just mean you get stuck between its toes after it tromps all over you.
Size: 41 to 59 feet (12.6-18 meters) in length and weighing it at upwards of 21 tons.
When They Lived: Early–Late Cretaceous, 112 to 93.5 MYA.
Distinguishing Features: The Spinosaurus is so named due to the presence of a large dorsal fin along most of its back. These were made of large extensions of their vertebrae and grew up to 5.4 feet (1.65 meters) from their body.
Why You Should Be Scared: If you watched Jurassic Park III, you already have a healthy fear of these incredibly large predators. It is believed they fed on fish and aquatic dinosaurs as well as terrestrial prey. Given its sheer size, it could certainly kill a human rather easily, but frankly, it could also just step on you, flattening you in the process.
Size: 30 feet (9 meters) in length and weighing it at approximately 3 tons.
When They Lived: Late Cretaceous, 76.6 to 75.1 MYA.
Distinguishing Features: Their most distinctive feature would have to be it’s tiny, useless forearms, which were typical of large theropod dinosaurs.
Why You Should Be Scared: These nasty critters come from the same family as the dreaded Tyrannosaurus Rex. Their size, speed, and particularly nasty teeth make them a dinosaur you probably wouldn’t want to stumble upon on a particularly “hungry” day.
Size: 11 meters in length with a weight of approximately four tons.
When They Lived: Late Cretaceous about 66 MYA.
Distinguishing Features: The Rajasaurus possessed a distinctive low rounded horn, which was made up of outgrowths from the nasal and frontal bones. They had small arms, which may have been somewhat useless, but their legs were massive and powerful.
Why You Should Be Scared: Well, you really shouldn’t. Unless you have a skeleton fall on you at a museum, you don’t have much to worry about. Now, if you happen to build a time machine and check one of these guys out while they were still romping about the supercontinent Godwana, they might chase you down and eat you without even batting an eye.
Size: 33 feet (10 meters) in length. Their forelimbs were particularly long, reaching up to 11.5 feet (3.5 meters) in total length.
When They Lived: Late Cretaceous, 70 MYA.
Distinguishing Features: These large theropods had a distinctive large set of claws extending from their forelimbs. These grew to a length of 3.3 feet (1 meter) in length.
Why You Should Be Scared: These large creatures possessed enlarged claws on their forelimbs, which were likely used as either offensive or defensive weapons. There is little known about the species as a whole, given the lack of substantial fossil evidence. However, from what has been uncovered, they grew very large, were likely predatory carnivores, and could literally skewer a human with their claws.