In 1982, the comic strip The Far Side jokingly referred to the set of spikes on a Stegosaurus’s tail as a “thagomizer”. A paleontologist who read the comic realized there wasn’t any official name for the spikes and began using the new word; Thagomizer is now the generally accepted term.


Thagomizer on mounted Stegosaurus tail

A thagomizer is the distinctive arrangement of four to ten spikes on the tails of stegosaurid dinosaurs. These spikes are believed to have been a defensive measure against predators.

The arrangement of spikes originally had no distinct name; the term Thagomizer was coined in 1982 by cartoonist Gary Larson in his comic The Far Side, and thereafter became gradually adopted as an informal term within scientific circles, research, and education.


A thagomizer on the tail of a Stegosaurus fossil

There has been debate about whether the spikes were used simply for display, as posited by Gilmore in 1914, or used as a weapon. Robert Bakker noted that it is likely that the stegosa… Continue Reading