Tail club

In zoology, a tail club is a bony mass at the end of the tail of some extinct animal species, most notably the ankylosaurids, some sauropods, glyptodonts, and some meiolaniid turtles. It is thought that this was a form of defensive armour or weapon that was used to defend against predators, similar to the thagomizer of stegosaurids. It is hypothesized that tail clubs were also used in intraspecific combat, specifically fighting for mating rights. The structure and size of tail clubs vary greatly between species. However, no known extant animals posses structures even resembling tail clubs.