Behavioral Ecology and Sociobiology

, Volume 62, Issue 6, pp 1027–1035 | Cite as

Friendships between males and lactating females in a free-ranging group of olive baboons (Papio hamadryas anubis): evidence from playback experiments

  • A. LemassonEmail author
  • R. A. Palombit
  • R. Jubin
Original Paper


Close association between an anoestrous female at the time of lactation and adult male(s) is relatively rare in mammals, but common in baboons (Papio hamadryas subsp.). The functional significance of these “friendships” remains unclear, however. In chacma baboons (P. h. griseipes), friendships are a counter-strategy to infanticide by immigrant males. Experimental playback of female distress calls in chacma baboons revealed that male friends are more motivated to protect females and infants than are control males. Olive baboons (P. h. anubis) also exhibit friendships, but infanticide is rare, suggesting that friendships provide females with protection from non-lethal aggression (anti-harassment hypothesis) or serve to promote male–infant bonds that later benefit the maturing juvenile (future male caretaker hypothesis). We replicated these playback experiments on a group of olive baboons to test between these hypotheses and to evaluate if the lower costs of non-lethal harassment lessens male protective responsiveness relative to protection from (more costly) infanticide. Spatial data revealed that most lactating females had one to four friend males. Relative to non-friends, friend dyads were characterized by higher rates of allogrooming and infant handling, but less agonism. Female rank was correlated with the number of male friends. Just as in chacma baboons, playback of female screams elicited stronger responses from male friends than control males in support the anti-harassment hypothesis. Compared to the chacma baboon, male olive baboons appeared to exhibit similarly high levels of protective solicitude for female friends although they protect against non-lethal harassment rather than infanticide.


Friendship Infanticide Lactation Playback Olive baboons 



We thank the Office of the President of Kenya, the National Museums and its Director General, Dr. I. Farah, and the Institute of Primate Research (Nairobi) for sponsorship and permission to conduct research in Laikipia district. We are grateful to John Ruggieri and Patrick Leparleen for allowing us to conduct research in the Segera area and to Philip and Janine Valentine for logistical assistance. We thank Stephen Karimi, Mohammed Abdi, and Francis Kokoe for their field assistance. We also thank Kristin Palombit for her significant contribution to maintaining the project. The research was supported by grants to RAP from the National Science Foundation (BCS 0117213), the L.S.B. Leakey Foundation, the Wenner–Gren Foundation, Rutgers University, and the Center for Human Evolutionary Studies (CHES, Rutgers University). The observations and experiments of that study comply with the current laws of Kenya.


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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Laboratoire d’Ethologie-Evolution-Ecologie, UMR 6552 – C.N.R.S.Université de Rennes 1PaimpontFrance
  2. 2.Department of Anthropology, Center for Human Evolutionary StudiesRutgers UniversityNew BrunswickUSA

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