Behavioural synchronization in a multilevel society of feral horses

AO_SCPLOWBSTRACTC_SCPLOWBehavioural synchrony among individuals is essential for group-living organisms. It is still largely unknown how synchronization functions in a multilevel society, which is a nested assemblage of multiple social levels between many individuals. Our aim was to build a model that explained the synchronization of activity in a multilevel society of feral horses. We used multi-agent based models based on four hypotheses: A) horses do not synchronize, B) horses synchronize with any individual in any unit, C) horses synchronize only within units and D) horses synchronize across and within units, but internal synchronization is stronger. Our empirical data obtained from drone observations best supported hypothesis D. This result suggests that animals in a multilevel society coordinate with other conspecifics not only within a unit but at an inter-unit level. In this case, inter-individual distances are much longer than those in most previous models which only considered local interaction within a few body lengths.