Dinosaurs Max's Random Ramblings

The Far Side of Stegosaurus’ Tail

Stegosaurus is most famous for its deadly tail spikes, referred to by paleontologists as “Thagomizers.” But where did the name thagomizer come from? And what does it have to do with a 1982 newspaper comic?

Have you ever heard the tragedy of Thag Simmons? I thought not. It’s not a story that the mainstream media would tell you.

If you are confused by the opening line, I don’t blame you (though I’m sure a few of you got the prequel joke). Thag Simmons is not a controversial Rockstar, nor is he a famous paleontologist or a legendary dinosaur specimen. No, Thag Simmons is a deceased caveman from a newspaper comic strip released in the 1980’s.

Yes, there is a point to Thag Simmons.

In 1982, American cartoonist Gary Larson released a comic strip starring Mr. Simmons as part of his celebrated “Far Side” comic strips. In the comic, a seemingly educated cavemen points to the tail of a Stegosaurus – specifically its infamous tail spikes – and refers to it as the “thagomizer,” a term named after, as he says, “The late Thag Simmons.” While this little comic was a cute little tongue-and-cheek gag for most, it turns out that some paleontologists pay close attention to the cartoons in the morning papers.

At the Society of Vertebrate Paleontology’s annual meeting in 1993, Utah paleontologist Kenneth Carpenter used “thagomizer” to describe the tail spikes of a Stegosaurus specimen. I must say that his decision was quite courageous, as I’m sure that standing in front of experts from across the world and proposing a name based on a comic with cavemen and dinosaurs (a big no-no in the field of paleontology) would have been quite intimidating. Yet Carpenter’s decision paid off, as the name managed to gather recognition within paleontology in the decades that followed. Various books, documentaries and museum displays have utilized “thagomizer” to describe stegosaur tail spikes with the Royal Ontario Museum’s Zuul exhibit specifically coming to mind in my own experiences.

Unfortunately, according to and the Merriam Webster dictionary, Thagomizer is not an official part of the English language. Rather, it is just a fun term used by paleontologists. Paleontologists rarely have the opportunity to invent and use new terminology, so the use of a unique term such as thagomizer is both rare and amazingly fitting. The word thagomizer sounds like a doomsday weapon made by a Bond villain, and based on the theorized uses that Stegosaurus and its kin had for it, it couldn’t be more fitting…

Copyright (c) 2015 Robert Esckelson

Works Cited

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

Stegosaurus and “friends” courtesy of Harrison Keller Pyle, found at his twitter here

Thagomizer cartoon courtesy of Gary Larson, found here

Allosaurus’ jaw ache courtesy of Robert Esckelson, whose work can be found here

  1. Black, Riley. “Watch Out For That Thagomizer!”, Smithsonian Institution, 30 Mar. 2011,
  2. “The Word: Thagomizer.” New Science, 8 July 2006.

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