The Most Dangerous Dinosaurs To Ever Exist

Picture this — it's 1676, and you're a museum curator in England tasked with identifying a huge, strange-looking "stone" that someone found in a limestone quarry. It looks like a bone to you — specifically, half of a femur — but it's way too big to belong to any animal you're familiar with. 

To his credit, Robert Plot figured out that he was actually looking at a petrified bone. However, since no one had heard of dinosaurs at the time, he suggested that it belonged to a giant human, as in the biblical sort. Over 80 years later, physician Richard Brookes made an even ballsier move — noticing the bone fragment's resemblance to a pair of testicles, he gave it the totally mature scientific name Scrotum humanum. It took 61 years before paleontologist William Buckland could give it a proper name (Megalosaurus), ending its whirlwind journey towards becoming the first non-avian dinosaur to receive a valid name.

Since then, scientists have come a long way from naming prehistoric predators. Experts now know, for example, that the "terrible lizards" called dinosaurs weren't really lizards. In fact, they're more closely related to birds, which are technically living dinosaurs. They also know from fossil analysis that quite a few of these animals were indeed quite terrible. Here are some of the most dangerous non-avian dinosaurs to ever roam the planet. (Sticking strictly to extinct dinosaurs, of course. Otherwise, birds like the cassowary would have a decent shot at making this list.)

Most people probably know Spinosaurus as the dinosaur from "Jurassic Park III" that made short work of T. rex (via Cinema Blend). Much of that interpretation of the sail-backed dinosaur turned out to be scientifically inaccurate, though. Spinosaurus was indeed a massive Mesozoic threat but in an entirely different manner from its Hollywood depiction.

Ernst Stromer described the first (and at the time, only) known Spinosaurus remains in the 1915. Twenty-nine years later, during World War II, a bomb destroyed them, leaving only Stromer's drawings intact (via National Geographic). Spinosaurus remained a mystery for decades, until the description of new specimens in the late '90s and early 2000s allowed scientists to further study this bizarre dinosaur. Experts now know that Spinosaurus was among the largest meat-eating dinosaurs ever (over 49-feet long, based on recent estimates), and that it likely led an aquatic or semi-aquatic lifestyle, as reported by Sci-News. Digital analysis of its fin-like tail revealed that Spinosaurus could have used it like a paddle, swimming with wide feet and nabbing prey with its narrow, sharp-toothed snout — a prehistoric "river monster" unlike any other dinosaur science knows of.

However, scientists still are not sure why it had a massive back sail. Previously, scientists suggested that it was for body temperature regulation, energy storage, scaring enemies, or attracting mates. A newer idea is that Spinosaurus could have used it to herd prey into a "bait ball," akin to sailfish and thresher sharks (via Cambridge University Press).

If the Cretaceous period had T. rex, the Jurassic period had Allosaurus. According to LiveScience, Allosaurus was likely powerful enough to take down dinosaurs that were nearly thrice its size.

Amazingly, a 2015 study found that Allosaurus could open its jaws nearly 16 degrees wider than Tyrannosaurus rex, In addition, Allosaurus had serrated, dagger-like teeth that curved backwards, likely to prevent its unfortunate prey from getting away (via the National History Museum). Meanwhile, a 2002 CT analysis of a cast of an Allosaurus' braincase showed striking similarities with crocodilian brains. It also suggested that Allosaurus may have had a particularly good ear for low-frequency sounds and was probably keen at detecting (but not necessarily evaluating) smells.

While Allosaurus was one of the most successful predators of its time, fossil evidence suggests that it wasn't above hunting — or even scavenging the corpses of — its own kind during lean times (as reported by ABC News). Still, experts regard Allosaurus to have been an active hunter, as evidenced by bones that sustained damage from what was likely a Stegosaurus defending itself with its spiky tail (via Smithsonian Magazine).

When paleontologists first described it in a 1995 paper, they thought that the approximately 41-foot-long Giganotosaurus was the largest meat-eating dinosaur that ever lived. And while experts now know that Spinosaurus was longer by a few feet, that doesn't make Giganotosaurus any less impressive (or dangerous). In fact, its sheer size meant that it was the top dog of its ecosystem.

One of Giganotosaurus' most noteworthy features is its thin, pointed tail. LiveScience explained how experts saw this as a hint of this gigantic predator's surprising agility — it could have acted as a stabilizer of sorts, maintaining the ferocious meat-eater's balance as it made sharp turns and chased after its prey. With its strong legs, scientists estimate that it could have reached a top speed of 31 mph while sprinting (compared to T. rex's approximate maximum running speed of 25 mph). Interestingly, some experts argue that Giganontosaurus could maintain its own body temperature regardless of its environment  (and grow really fast).

Due to its relatively weaker bite force than T. rex's, Giganotosaurus likely took down its prey by slicing its target's flesh, wounding its prey, and wearing it down to the point where the predator could easily overpower it.

The second plant-eater on this list, Argentinosaurus, is here because of one big reason — it was, well, big. In fact, it may have been one of, if not the biggest land animal to walk the planet. Since paleontologists have yet to find a complete Argentinosaurus skeleton, they had to work with whatever remains were available, as explained in a Phys.org article. Using some vertebra and leg bones, experts were able to estimate the late Cretaceous long-neck's length and weight — roughly 119.75 feet long and approximately 100 tons.

SyFy Wire speculated that super-sized sauropods like Argentinosaurus were able to thrive precisely because of their immense bulk. After all, since it would take even a large-sized meat-eater like Tyrannosaurus or Giganotosaurus too much time and effort to take down a single sauropod, it makes sense that they'd go after smaller, easier targets instead.

And of course, there's the possibility of getting crushed under Argentinosaurus' massive foot. In 2019, researchers described a rare fossil find from the Jurassic period — a prehistoric turtle seemingly squished by a sauropod (via Scientific American). Now imagine what an Argentinosaurus' foot could do.

The mere thought of a shark can make people feel extremely terrified and uneasy. This is largely thanks to how pop culture has depicted the marine macropredator over the years (looking at you, Steven Spielberg). It's not really that surprising, then, that a dinosaur with teeth similar to a great white shark's would end up being named after it.

A 2019 article on Reuters described Carcharodontosaurus as one of the best-known species of its group — and as it turns out, there's a good reason behind its shark-like chompers. As paleontologist Soki Hattori explained, "The teeth of carcharodontosaurs, including Carcharodontosaurus, exhibit characteristic undulations of the surface along the margin of the thin, blade-like 'shark-tooth.'" This means that these predators were likely able to tear the flesh off their targets with minimal effort.

Aside from its size and terrifying teeth, experts like Donald Henderson of the Royal Tyrrell Museum say that Carcharodontosaurus also had strong jaws and neck muscles (working in conjunction with its center of mass) going for it. Henderson shared in an interview with Inverse that at least one particular species of Carcharodontosaurus, C. saharicus, could have lifted an animal weighing up to 935 pounds in its mouth. (For a bit of perspective, that's about three dirt bikes!)

Typically portrayed as the yang to T. rex's yin, Triceratops is easily one of the most popular and instantly recognizable dinosaurs of all time. A quick look at this three-horned tank could easily show how this archetypal ceratopsian survived all the way to the end of the Cretaceous period.

People compare Triceratops to today's elephants and rhinos due to its size and stance. According to LiveScience, this 30-foot, 11,000-pound dinosaur stood on straight legs and possessed one of the largest heads of any land animal to ever exist. Above each eye was a long and pointy horn made of bone, which could have been used for stabbing and goring attackers. A third, smaller horn grew right above its nose. Meanwhile, its huge frill may have protected its neck or attracted potential mates. Triceratops' skull connected to the rest of its body via a ball-and-socket joint. According to experts, this one-of-a-kind adaptation allowed Triceratops to rotate its head nearly 360 degrees and deal with threats from any direction.

A 1996 analysis of Triceratops bones revealed tooth marks from T. rex, suggesting that it did try to make the horned plant-eater part of its diet. Other paleontologists found proof of Triceratops surviving T. rex attacks, thanks to bones that partially healed from T. rex bites. Sadly, the idea that it charged at opponents like a bulldozer. is likely untrue Nevertheless, its unique characteristics made Triceratops one of the most remarkable — and dangerous — herbivorous dinosaurs of its time.