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 ‘multiplebout’
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. Multiplebout
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.