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You’ve seen the scenario a million times.
An Ankylosaurus is grazing by the pond in Late Cretaceous North America. Suddenly, he is alerted by the presence of a hungry carnivore, Tyrannosaurus Rex. The predator lunges at him, hoping to attack the soft underbelly. However, the Ankylosaurus lowers his belly to the ground, and swings his clubbed tail at the T. rex’s ankle, breaking it. The carnivore limps away, defeated.
Or conversely, a Stegosaurus is minding his own business, foraging through the ferns, when a hungry Ceratosaurus attacks. The Stegosaur stands his ground, and with a swing of his spiked tail, hits the ceratosaur across the face. The Ceratosaurus is stunned and bloody, and leaves in search of easier prey.
Or perhaps you’ve seen this. A Diplodocus herd is stopping at the river bed for a drink, when a Torvosaurus emerges from the forest to pick off a young herd member. The older ones protect the youths, and whip their tails in the air, making a cracking sound. The Torvosaurus remains undeterred, and moves closer. He is then met with a whip to the face, hitting his eye. Blinded, he runs off defeated, while the Diplodocus herd continues their day.
Here at Trope-osaurus, I like to talk about certain cliche’s and behaviors that pop up constantly in dinosaur art and pop culture, and whenever a hungry theropod is going after a stegosaur, an ankylosaur, or a diplodocid, always expect some tail swinging. But is this behavior something that is backed up with science?
When scientists find weird horns, spikes, and clubs on the tails of dinosaurs, one of the first conclusions they would come up with was that they were used for self defense against predators. This certainly makes a lot of sense, but in reality, this is one of those behaviors that is more based on hypothesis than actual evidence.
Remember how it was hypothesized that Pachycephalosaurus used it’s domed skull to head butt rivals, and that this was depicted so many times that it was eventually just considered fact by the general public, despite there being no direct evidence of such behavior? This is a similar situation.
There have been less exciting explanations for what these dinosaurs used their tails for. Let’s take a look at the ankylosaurs for a while.
It has been suggested by some that the tail instead could have been brightly colored or used as a way to attract mates. Perhaps the bigger the club the more desirable the male? Or they could have used them in inter-species disputes, with males fighting each other by bashing their sides with their clubs. Glyptodont’s are often depicted engaging in such behavior.
However, the tail club being used as a weapon isn’t an especially silly idea, and does make a lot of sense. I will admit it looks pretty weird in some older paleo art, though. you know, when the ankylosaur is incredibly small and the T. rex is in a man-in-a-suit tripod posture.
Diplodocids are a slightly different story. It has been long suggested that the long, whip like tails could have been used like, well, a whip. Sauropods like Diplodocus, Apatosaurus, and Barosaurus could have used their tails as weapons, hitting their foes across the face. This behavior is seen in the television show Dinosaur Revolution, where a young Allosaurus is hit across the jaw by the tail of a Dinheirosaurus.
Well, that looks painful.
It has even been suggested that the tail could have made a loud cracking noise, like an actual whip, and the noise was used to scare away predators.
When you look at the tail, you can definitely see why someone may come to that conclusion. However, some scientists have expressed doubt over this theory. They suspect that the tail bones would have been to weak to act as a whip, and such a high velocity impact would actually break the bones in it’s tail.
However, I don’t think that definitely means sauropods couldn’t use their tails as weapons. Perhaps they didn’t use their tails exactly like whips (only using the tip) but a hit with the entire tail would certainly knock a carnivore off it’s feet.
So, what about Stegosaurus?
The spikes on it’s tail certainly seem like they could be used for defense. We have a bit more direct evidence of this than the other ones, though.
This article shows that a whole was found in an Allosaurus’ pelvis bone that perfectly fits the thangomizer of a Stegosaurus.
You know what that means?
Stegosaurus hit Allosaurus in the crotch!
Dude, what is wrong with you?
So then, what is my stance on this issue. Well, I’m certainly not against it, I like the idea of these dinosaurs using their tails as weapons. I just like to look at things like this at all angles, and consider all the possibilities. What I don’t like is when a hypothesis becomes so popular that it becomes treated like common fact. Although it would make sense that these dinosaurs used their tails as weapons, the fact of the matter is we really don’t know for sure, and we shouldn’t act like we do. Dinosaurs were probably much weirder than we could ever imagine, and they probably did things that didn’t make sense. Sometimes the most probable theory doesn’t turn out to be the correct one.
BTW, I want to see more hadrosaurs using their tails as weapons. They may have not has whips or clubs or spikes at the end of their tails, but look how thick they are! You can’t tell me a swing from that couldn’t knock a predator off it’s feet!
Thank you Disney!
Theropod’s too? Heck, why not!?
Join me next time as I review the Dinosaur episode of Bill Nye The Science Guy. How has our understanding of dinosaurs changed since the early 90’s? I think you know the answer.