Sex differences in behaviour of the mongolian gerbil (Meriones unguiculatus) in encounters between pairs of same or opposite sex

Pairs of gerbils were observed in mixed-sex and single-sex encounters in a neutral arena using a round-robin technique: various acts and postures were described and their frequency analysed. In single-sex encounters' males showed more social investigation, footstomping and marking while females engaged more frequently in jumping, grooming and chewing. Both sexes showed comparable levels of agonistic behaviour. In mixed-sex encounters, agonistic behaviour was markedly increased due to the aggressiveness of the females, usually in response to sexual investigation by the male. Males never attacked females. High levels of footstomping and marking with the ventral scent gland were characteristic of males in the presence of unreceptive females. Lordosis was only observed in three out of one hundred tests.