In zoology, a club is a bony mass at the end of the tail of some dinosaurs and of some mammals, most notably the ankylosaurids and the glyptodonts. It is thought that this was a form of defensive armour or weapon that was used to defend against predators, much in the same way as a thagomizer, possessed by stegosaurids, though at least in glyptodonts it is hypothesized it was used in fighting for mating rights. Among dinosaurs, the club was present mainly in ankylosaurids, although the sauropodShunosaurus also possessed a tail club. The tail club is most often depicted on Ankylosaurus, especially in encounters with larger predators such as Tyrannosaurus. Whether Ankylosaurus was actually able to swing its tail with enough force to prove unassailable or not however is yet to be proven.