A sociogram for the cranes of the world

The behavioral repertoire for the world's 15 species of cranes includes over 100 behavioral acts with clear social significance. Each species performs at least 60 discrete social postures, vocalizations, displays, and activities. Because all but a handful of the stereotyped social displays are common to all species, the presence or absence of social displays was useful only to a limited degree in comparing the relatedness of established crane taxonomic groups. However, the breadth of the repertoire for each species and for the family Gruidae tentatively places cranes at the apex of social complexity (at least for stereotyped displays) in the animal world. (C) 1998 Elsevier Science B.V. All rights reserved.