The Most Ludicrous Dinosaur Extinction Theories

Have you ever felt the burning desire to correct your teacher, consequences be dammed?

If so, you can relate to my first day of grade 11 history class.

As a preface to the start of human history, our teacher gave my class a grand lecture about the history of our planet. For the first few billion years, the accuracy of the material and his enthusiasm in presenting had me fully captivated. All was going exceedingly well… until he hit the extinction of the dinosaurs.

His explanation for why the dinosaurs went extinct went something like this: About 65 million years ago, an asteroid hit the earth in the Gulf of Mexico (correct). The impact created a dust cloud that blocked sunlight for a long amount of time (also correct). The dust cloud blocked off the sun from areas around the equator, where dinosaurs lived, and did not block polar regions, where mammals survived because they were adapted to the cold while dinosaurs were not.

…I’m sorry, what?

Problem number one: The dust cloud would have surrounded the entire world, not just the equator. Problem number two: Since dinosaurs were likely warm-blooded, they would have been able to survive the cold almost as well as mammals, especially theropods that had the benefit of feathers covering their bodies. The third problem, my personal favorite (if you can call it that,) is that dinosaurs did live in polar regions, as their fossils are known from both the Arctic and Antarctic.

After hearing my teacher explain this, it made me cringe to the point of near madness. When I calmed down, it struck me that the curriculum may have been slightly outdated. However, my teacher’s strange hypothesis is far from the most outlandish theory on why the dinosaurs went extinct. In this article, I will name my five picks for the most ludicrous dinosaur extinction theories and discuss why they are ridiculous.

The Mammals Took my Babies!

Were the dinosaurs devoured by our earliest mammalian ancestors? In the opinion of early paleontologists, they certainly were! Well, at least their babies were. According to this theory, the dinosaurs went extinct because they abandoned their eggs once they were laid, leaving their young vulnerable to predation. The first mammals took full advantage of this, devouring the defenseless eggs to the point where they caused a global dinosaur extinction.

Where do I start? First, dinosaurs were surprisingly good parents. Nesting sites have been discovered across the world, with some even containing parents sitting atop their eggs in death. If that doesn’t constitute good parenting, then I don’t know what does.

The second major issue is that dinosaurs and mammals lived alongside each other for most of the Mesozoic period. The earliest mammals appear in the fossil record during the early Jurassic period, some 180 million years ago. They would continue to live alongside dinosaurs for the next 115 million years, until the dinosaurs’ extinction. If mammals lived alongside dinosaurs for that long, why did they not wipe out the dinosaurs earlier?

The final problem, which goes without saying, is that it would be impossible for mammals to eat every dinosaur egg across the planet. Even suggesting that Mesozoic mammals – animals that at their maximum only grew to the size of a racoon – managed to wipe out the dinosaurs is preposterous. While they did eat dinosaur eggs on occasion, it wouldn’t have made a massive impact on their population, thus debunking this theory.

The Very Hungry Caterpillars?

In 1962, a paper was released by insect expert Stanley Flanders that theorized that the dinosaurs were outcompeted and killed off – by caterpillars. The paper theorized that caterpillars devoured the plant supply that herbivorous dinosaurs relied on, leading them to extinction and in turn, the carnivorous dinosaurs as well. Umm….

This theory raises so many questions. If caterpillars were so devastating, then how are there plants around today for herbivores to eat? Since caterpillars – like mammals – lived alongside dinosaurs for millions of years, then why didn’t they outcompete the dinosaurs earlier? If caterpillars munched their way through the Cretaceous, then shouldn’t their fossils be extremely common? One other big problem with both this theory and the mammal egg theory is that neither account for the demise of marine reptiles like mosasaurs and plesiosaurs. These animals would have been unaffected by caterpillars and mammals eating dinosaur eggs and food, making the theories even more problematic.

Short on Sight…

Every so often, professionals in other fields will give their two cents on paleontology with varying results. On one occasion, it helped to reveal that a dinosaur suffered from a form of cancer that affects humans. On another, it led to an unorthodox theory of dinosaur extinction: that they all died due to eye cataracts (film over the eyes). In 1982, ophthalmologist L.R. Croft proposed that the crests and horns of dinosaurs evolved as unsuccessful protection from harsh sunlight. He surmised that this was not enough protection however, as the sun caused cataracts to develop in the eyes of dinosaurs, making them blind and leading to their extinction. This so called “theory” feels more like a publicity stunt for Dr. Croft than a legitimate academic hypothesis, to be frank. If the Mesozoic sun was so problematic, then why didn’t other animals encounter the same fate as the dinosaurs? The answer is simple: the sun wasn’t overly dangerous to anyone’s eyes and this theory is blindingly idiotic.

Too big – and too dumb – to Survive?

Long before the age of feathers and colours, dinosaurs were thought of as lumbering swamp monsters. For decades, it was thought that the only way dinosaurs could support their massive bodies was to live exclusively in swamps and ponds. As if this wasn’t bad enough, it was also believed that dinosaurs were incredibly stupid – even to the extent that they became too dumb to survive. Indeed, it was widely accepted that dinosaurs became too big for their tiny brains, which in turn led them to go extinct. In the process of writing this article, my grandmother confirmed that this is what she was taught in school; that the dinosaurs died due to stupidity.

For this theory, I will directly quote the 1955 book “Animals of Yesterday.” My reasoning for doing this is not to humiliate the writer; rather, I intend to present a detailed view into the rationale of past paleontologists regarding dinosaur extinction. Observe:

“As you have seen, giant dinosaurs were once lords of the earth. Why did they disappear? You can probably guess part of the answer – their bodies were too large for their brains. If their bodies had been smaller and their brains larger, they might have lived on.” (Parker: 10)

As I’ve mentioned on this website, dinosaurs weren’t the sluggish, reptilian monsters they were once portrayed to be. New specimens and advanced research into their biology and behaviours have revealed intelligent and complex animals that were well adapted to almost every environment. While some dinosaurs did have infamously tiny brains (good old walnut-brain Stegosaurus comes to mind,) it didn’t mean they weren’t able to function like any other animal. If jellyfish could thrive for the last 500 million years without brains, then I’m sure that dinosaurs like Stegosaurus could manage with a relatively small one.

The Little Green Men.

Believe it or not, there are some people that believe that aliens are responsible for the extinction of the dinosaurs. In writing this article, I was lucky enough to stumble across an episode of the History Channel propaganda piece Ancient Aliens that was dedicated to “discussing” this very topic. For just about an hour, I alternated between laughing out of my seat and yelling at the screen. There was so much lunacy fit into one episode that I couldn’t possibly include everything into this article (hint-hint). I have just one thing to say: aliens don’t exist, and even if they did, they didn’t kill off the dinosaurs.


I do not take credit for any images found in this article.

Header image courtesy of Mark Garlick, found here

Mammals eating dinosaurs’ courtesy of Misaki Ouchida, whose work can be found at her website here

Swamp Brontosaurus courtesy of Charles Knight, found here

Tyrannosaurus stare down courtesy of Universal Pictures’ film Jurassic Park, found here

“Ancient Aliens: Aliens and Dinosaurs.” Season 4, episode 10, 2012.

Benton, M. J. Dinosaurs Rediscovered: The Scientific Revolution in Paleontology. Thames & Hudson, 2020.

Black, Riley. “The Top Ten Weirdest Dinosaur Extinction Ideas.”, Smithsonian Institution, 5 Aug. 2013,

Parker, Bertha Morris. Animals of Yesterday. 1955.

Pickrell, John. “How the Earliest Mammals Thrived alongside Dinosaurs.” Nature News, Nature Publishing Group, 23 Oct. 2019,

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