Defense against predators is one possible purpose – although the frills are comparatively fragile in many species – but it is more likely that, as in modern ungulates, they were secondary sexual characteristics used in displays or for intraspecific combat.

The massive bosses on the skulls of Pachyrhinosaurus and Achelousaurus resemble those formed by the base of the horns in modern musk oxen, suggesting that they butted heads.

Centrosaurines have frequently been found in massive bone beds with few other species present, suggesting that the animals lived in large herds.

[3] In 1997, Lehman argued that the aggregations of many individuals preserved in bonebeds originated as local "infestations" and compared them to similar modern occurrences in crocodiles and tortoises.

[3] Modern animals with mating signals as prominent as the horns and frills of ceratopsians tend to form these kinds of large, intricate associations.

[5] He finds commonality between the slow growth of mating signals in centrosaurines and the extended adolescence of animals whose social structures are ranked hierarchies founded on age-related differences.

[5] In these sorts of groups young males are typically sexually mature for several years before actually beginning to breed, when their mating signals are most fully developed.

[9] According to Scott D. Sampson, if ceratopsids were to have sexual dimorphism modern ecological analogues suggest it would be in their mating signals like horns and frills.

[16] The clade Ceratopsidae was in 1998 defined by Paul Sereno as the group including the last common ancestor of Pachyrhinosaurus and Triceratops; and all its descendants.

[18] Ceratopsidae was given an official definition in the PhyloCode by Daniel Madzia and colleagues in 2021 as "the smallest clade containing Centrosaurus apertus, Ceratops montanus, Chasmosaurus belli, and Triceratops horridus".