Behaviours of collared and white-lipped peccaries (Tayassu tajacu and T-pecari) in relation to sexual receptivity of the female

Changes in behaviours of the two peccary species, Tayassu tajacu Linnaeus, 1758 and T. pecari Link, 1795 between non-receptive and receptive periods w ere followed by presenting females to males daily for 15 minutes. In T. taj acu, the rank order of behaviours, similar in both sexes during the non-rec eptive period, differs during receptivity. Contact behaviours decrease in m ales, whereas sexual ones progress. The same tendency appears in females. I nhibited bites replace markings of partner as the most common behaviour in both sexes. In T. pecari, the rank order of behaviours always differs betwe en sexes. When females become receptive, the differences from the non-recep tive period are neither numerous nor significant. The most common behaviour of males, previously markings of partner, becomes mounts, whereas in femal es agonistic behaviours reinforce their dominance. In this species, the onl y behaviours that increase are those leading directly to copulation or thos e of an agonistic nature. In both species, females show more agonistic beha viours than males (mainly inhibited bites in T. tajacu, truly aggressive on es in T. pecari). When females are receptive, males of T. pecari become les s active, contrary to T. tajacu where both sexes double their activity. In T. tajacu, most behaviours vary significantly in relation to the progestero ne level, contrary to the other species. These pecularities appear correlat ed to herd composition and organisation.