THE POST-COPULATION WITHDRAWAL RESPONSE IN FEMALE BABOONS - A FUNCTIONAL-ANALYSIS

Rapid withdrawal of females from males at the end of the copulatory se quence (prior to male dismounting) characterizes several primate speci es. The purpose of this paper is to make a preliminary investigation i nto possible functional aspects of these ''copulatory darts.'' Two hyp otheses are proposed; (1) females use darts to aid competing males to locate the source of copulation calls; and (2) females dart in order t o promote re-mating with the same male. Both hypotheses postulate that darts may thus enhance male-male competition, although acquisition of other benefits may be the primary drive to darting according to the r e-mating hypothesis. Using data from 157 copulations collected from si x females spread across four groups in a wild population of chacma bab oons Papio cynocephalus ursinus, darting behaviour is described. Withi n females, darting distance is highly variable. Darting distance is gr eatest at the time of ovulation (and maximal sexual swelling), and the re is some evidence that darting may also be more frequent, and cover greater distances, when the mating male is adult rather than juvenile. While darting behaviour appears unrelated to the presence or absence of ejaculation, it tends to correlate positively with the duration of the female copulation call. These preliminary results are consistent w ith a mediating role in male-male competition and therefore provide su pport for both hypotheses.