Agonistic interactions during competition for different resources in captive European wild pigs (Sus scrofa)

We observed a group of captive wild pigs to determine how agonistic encounters vary as a function of preceding activities and with the availability and distribution of resources. Data are presented supporting previous competition hypotheses. The frequency and intensity of encounters was highest during competition for resources that were limited and defendable. Activities associated with limited but undefendable resources were followed by fewer encounters which were of lower intensity. When unlimited and undefendable resources were involved, agonistic encounters were infrequent. Comparisons with earlier work show that patterns of agonistic behavior in groups of Sus scrofa, regardless of the environmental setting, are not simply related to the preceding activity per se, but are related systematically to the availability and distribution of resources associated with that activity. A short-term decrease in the tendency of one male to displace its rank neighbor, not encompassed by familiar notions of rank-neighbor relations, was discovered. A previously undescribed visual display used to prevent or inhibit aggression was observed.