Decision‐Making in Przewalski Horses (Equus ferus przewalskii) is Driven by the Ecological Contexts of Collective Movements

Abstract

We addressed decision‐making processes in the collective movements of two groups of Przewalski horses (Equus ferus przewalskii) living in a semi free‐ranging population. We investigated whether different patterns of group movement are related to certain ecological contexts (habitat use and group activity) and analysed the possible decision‐making processes involved. We found two distinct patterns; ‘single‐bout’ and ‘multiple‐bout’ movements occurred in both study groups. The movements were defined by the occurrence of collective stops between bouts and differed by their duration, distance covered and ecological context. For both movements, we found that a preliminary period involving several horses occurred before departure. In single‐bout movements, all group members rapidly joined the first moving horse, independently of the preliminary period. In multiple‐bout movements, however, the joining process was longer; in particular when the number of decision‐makers and their pre‐departure behaviour before departure increased. Multiple‐bout movements were more often used by horses to switch habitats and activities. This observation demonstrates that the horses need more time to resolve motivational conflicts before these departures. We conclude that decision‐making in Przewalski horses is based on a shared consensus process driven by ecological determinants.

Decision‐making Processes in Group Departures of Cattle

“…2009). This also contrasts with results from other species for which it was reported that the first departing individual moves from the group edge (Boinski 1996; Bourjade et al. 2009; Ramseyer et al.…”

“…In equids ( Equus sp.) stallions herd mares and offspring by approaching them from the back and push them (Waring 1983; Bourjade et al. 2009).…”

The Organization of Collective Group Movements in Wild Barbary Macaques (Macaca sylvanus): Social Structure Drives Processes of Group Coordination in Macaques

“…It is defined as the “period preceding the departure of the initiator” and is “delineated by the presence of pre-departure behaviours” [15]. Its quality, intensity and simultaneity are thought to influence the decision-making process [20], [21]. Pre-departure behaviour is interpreted as “voting” or negotiating for a certain direction [22], [8], [9] and group members try to reach a quorum threshold for departure [15] via vocalizations (e.g.…”

“…Other studies attributed the direction of the group to knowledgeable individuals [18]. Additionally, the precise progression of the remaining group members order may give insight to processes underlying consensus decisions [25].The joining behaviour may be crucially influenced by social relationships in species where individual recognition is possible [21] and affiliative relationships have been shown to mediate coordination in non-human primates [19], [26]. Furrer et al [34] stressed that the role of initiators can be influenced by a variety of variables which may apply for the progression order was well.…”

Recruitment and monitoring behaviors by leaders predict following in wild Barbary macaques (<i>Macaca sylvanus</i>)

“…We described that during the pre-departure period both the initiator and other, mainly adult group members show pre-departure behavior (e.g., back glances) in the majority of initiation attempts. Pre-departure behaviors may serve as indicators of the willingness to move further in a certain direction at a certain time (Bourjade et al, 2009;Bourjade and Sueur, 2010;Sueur et al, 2010b). In our former analyses, we focused on the individual characteristics of predeparture displaying individuals and initiators of collective movements.…”