The Most Bizarre Dinosaurs That Ever Existed

For 180 million years, dinosaurs reigned over every corner of the Earth’s surface. During this period of natural history, known as the Mesozoic era, these prehistoric titans evolved to fit nearly every habitat and niche under the sun. The results were some of the most amazing creatures to ever walk the Earth, with many unique shapes and body types that would never be seen again. While there are plenty of wrong things people used to think about the dinosaurs - like most of them are vicious monsters - not all of these animals are defined by their teeth and claws. Some are cute, others are impressive, and a few are just downright weird.

The fossil record is full of scary extinct dinosaurs, with some of the crazy dinosaurs sporting some of the most bizarre adaptations thanks to evolution. There are dinosaurs that managed to grow stubbier arms than the T. rex, while at least one looked like a buck-toothed chicken. Their are bird-like dinosaurs who rock primitive feathers and others that are covered in spines, scales, and armor. These bizarre-looking dinosaurs you won't believe are real shining examples of just how strange evolution can be and how dinosaurs truly are some of the most interesting animals to ever exist.

Carnotaurs have a devilish reputation - that's because they sport a set of distinctive horns unique among large, carnivorous theropods. Even the name carnotaurus translates from Latin as “meat-eating bull,” a direct reference to their horns and vicious appearance. What made them even more deadly were their powerful leg and tail muscles, which allowed them to sprint in short, rapid bursts of speed.

While its horns are one of carnotaurus’s defining features, a subtler feature may prove to be even more bizarre. Carnotaurus had remarkably short arms that measure only a foot and half long - tiny compared to the rest of its body. They are much shorter than those of the T. rex, another theropod known for their small arms. Scientists believe their arms were most likely vestigial remnants and probably served no real purpose in their day-to-day lives.

This scary-looking guy was a small, bird-like dinosaur who lived between 152 and 168 million years ago. Although they sported a primitive form of feathers, they are actually not a direct ancestor to birds. However, epidexipteryx helped scientists better understand some of the transitional stages between dinosaurs and birds. 

Epidexipteryx could not fly, so researchers believe its feathers may have evolved purely as a form ornamentation, perhaps making them more attractive to prospective mates. However, they may not have been stranded on the ground either. Their hands feature several long, narrow fingers that could possibly have been used to climb or extract insects from trees, much like the modern aye-aye. As epidexipteryx is rather small, it would make sense that an arboreal lifestyle would help in keeping them safe from terrestrial threats.

This odd theropod is Concavenator corcovatus, a carnivorous dinosaur that roamed Europe about 130 million years ago. The noticeable hump on its back is unique for these types of dinosaurs, and it has left scientists puzzled since its discovery in 2003. Researchers have thrown out all sorts of theories about the hump, speculating it could be used for mating, storing fat, or maybe that it was purely decorative. Another one of concavenator’s bizarre features are the bumpy protrusions on its arms.

These are similar to the anchor points for modern bird feathers, but scientists believed concavenator most likely had non-scale protrusions that dangled from them. The debate is still ongoing as to the true nature of these strange knobs.

Linhenykus monodactylus is a small dinosaur in a group of species known as alvarezsaurs, whose membership consists of bipedal dinosaurs with absurdly tiny arms. This particularly species inhabited the area which would become Mongolia between 84 and 75 million years ago, and it is unique among the alvarezsaurs. Unlike its close relatives, who all have multiple fingers, linhenykus only has the one, heavily-clawed finger. This makes linhenykus the only known dinosaur to possesses a single finger per arm, a trait which is unusual even to this day.

It is unclear exactly why linhenykus and its relatives had such tiny arms, but there is one theory floating around in the paleontological community. It is hypothesized linhenykus used their thick claws to dig at ants hills and termite mounds to break in and feast on the small insects hiding inside. These creatures were very small, able to fit in the palm of your hand, and could have subsisted on an insectivorous diet.

The pachycephalosaurus is famed for it’s remarkably thick skull, the top of which is a bony dome that is some nine inches thick. Amazingly, their skulls are known to transform in shape as they age, fooling many scientists for a while into believing the different life stages of these animals were actually completely different species.

It is hypothesized these dinosaurs used their hardened skulls to butt heads with rivals over mates, although some scientists believe their vertebrae could not have been strong enough to survive these impacts without causing serious injury. The debate has raged in the paleontological community since the discovery of these creatures, and many studies have been conducted to try and figure this out. One study showed that up to 22% of all species of pachycephalosaurus show signs of cranial injury, giving more credence to the theory they were natural head-butters. Others believe the domes were purely ornamental, but it doesn't seem like we will get a definitive answer anytime soon.

Therizinosaurus could be found roaming around in Central Asia between 75 and 70 million years ago. While these monstrous beasts may look like the dinosaur version of Edward Scissorhands, they were probably gentle giants who only used their claws for self defense and to gather food. Their claws are believed to be the longest in animal history, and are able to grow over three feet in length. Unfortunately, a full skeleton has never been discovered for this animal, so there are many unanswered questions as to what the therizinosaurus was really like. Scientists have not even found a skull, so we can’t even be sure of what or how they ate.

These bizarre dinosaurs have long been misunderstood by the scientific community, but the misconceptions are finally being addressed. After an oviraptor skeleton was discovered near a nest of fossilized dinosaur eggs, a theory emerged suggesting oviraptors might have been specialized egg thieves. Scientists thought the discovered oviraptor was caught in the act and killed by a protective mother. Its unusual, beak-like mouth was pointed to as further evidence that oviraptors fed by cracking open eggs and slurping out the contents. While that’s all gross and fascinating, it turns out that it’s not actually true.

The eggs discovered with the oviraptor were mistakenly believed to belong to a protoceratops, a small dinosaur related to the much larger and more famous triceratops. However, subsequent discoveries indicate the eggs did not belong to the small ceratopsian, but actually the oviraptor itself. While the evidence once characterized oviraptors as heartless baby stealers, that idea has morphed into quite the opposite. We now know these theropods were devoted mothers who chose to stay and look after their nests.

Kentrosaurus takes the armored spines made famous by its cousin the stegosaurus and pushes the idea one step further. Not only do they sport the iconic vertical plates on their shoulders, but those plates transform into deadly spikes as they travel down the kentrosaurs back. Two of those spines jut directly out of their front legs, and the ones on its tail can be swung around like a prehistoric morning-star. These incredibly badass tail-spikes go by the equally badass name "thagomizers." 

These massive herbivores get their name from their distinctive spikes, which evolved to pose a formidable challenge for potential predators. Researchers have studied the physics behind the kentrosaurs body to better understand just how powerful they may have been, and the results are fascinating. The kentrosaurus had a flexible skeleton that allowed it to move and turn with ease, ensuring predators couldn’t sneak up on them. They used their long, muscular tails as massive spiked clubs and could swing them at a maximum speed of 89 mph. Paleontologist Heinrich Mallison described the force as powerful enough to shatter ribs and pierce flesh, and even said the speeds achieved by the tail were “greater than those sufficient to fracture a human skull.”

Possibly one of the most absurd creatures to ever walk the Earth, incisivosaurus is a buck-toothed dinosaur that lived 128 million years ago. This bird-like dinosaur is unique for it’s bizarre teeth, a rare quality in animals outside of mammals. Most reptiles have one type of tooth, but incisivosaurus had both smaller, sharper teeth, as well as their distinctive front teeth. Some scientists believe they were either herbivorous or omnivorous, another trait that makes them distinct.

Amazingly, their strange physiology helped reveal some major secrets about another type of dinosaur, the oviraptor. It was believed oviraptors may have been birds who had simply lost their ability to fly, but it was later discovered incisivosaurus had actually been an early ancestor to the oviraptors, disproving the theory they came from birds.

These petite ceratopsians were a contemporary of their cousin, the triceratops, and the two could be found throughout North America. Unlike the triceratops, they had no horns and ran around on two legs. It’s an interesting bit of natural history that all dinosaurs started out as bipedal, and then many independently evolved the quadruped form. As herbivores, the leptoceratops would scurry on the ground, rooting up vegetation with their pronounced beak. They lived at the very end of the dinosaurs time on earth, only existing for about 50 million years before the extinction event that ended the Cretaceous period and wiped out nearly all of the dinosaurs.