Friendship, fatherhood, and MHC in baboons

Male-female ‘friendships’ among baboons have long interested researchers  (Palombit et al., 2001; Palombit et al., 1997; Smuts, 1985). Friendships are often described close, affiliative bonds between conspecific individuals  (Silk, 2002). Males may form friendships with females in order to acquire mating opportunities, or protect their offspring. Likewise, females may compete for male friends in order to gain protection for their offspring against potentially infanticidal males  (Palombit et al., 2001). This form of ‘friendship’ is common in chacma baboons (Papio ursinus) where non-resident males are likely infanticidal when climbing the dominance hierarchy  (Beehner & Bergman, 2008; Engh et al., 2006). While the females clearly benefit from male ‘friends’ protecting their infants, it is unclear if males gain similar benefits—mostly because the relationship between paternity, male-infant bonding, and male-female (mother) bonding has not been fully explored. New research sheds light on the proximate mechanisms by which males may identify their potential offspring and provide subsequent paternal care in chacma baboons  (Huchard et al., in press).

Huchard and colleagues demonstrate through genetic paternity testing that male chacma baboons are most likely the fathers of their friends’ infants. However, father-offspring dyads exhibited dissimilar major histocompatibility complex (MHC) alleles, suggesting the proximate means by which males figure out who their offspring is unclear.  Of the 17 infants in the studied population, their mother’s male friend (Huchard et al., in press) fathered 15. Also in their study, Huchard and colleagues compared father-offspring dyads with unrelated male-infant dyads to determine if fathers are more likely to share MHC Class II (DRB) haplotypes with their offspring. These  genes (MHC) are thought to be associated with body odor (although this not conclusive). In other words a male baboon might be able to figure out who his kid is if he smells enough like his daddy. Father-offspring dyads were shown not to share these specific MHC genes with their offspring, suggesting that if male baboons are recognizing who their kids are in order to protect them then they are doing it through some other way. It is possible (and indeed probable) that cues such as mating history and consistent association (via female/mother friend) influence the male’s ability to ‘perceive’ who his offspring truly is.

PS- If you are still home for the holidays, ask your mother if you smell like your father.

Beehner, J. C., & Bergman, T. J. (2008). Infant mortality following male takeovers in wild geladas. American Journal of Primatology, 70(12), 1152-9.

Engh, A. L., Beehner, J. C., Bergman, T. J., Whitten, P. L., Hoffmeier, R. R., Seyfarth, R. M., et al. (2006). Female hierarchy instability, male immigration and infanticide increase glucocorticoid levels in female chacma baboons. Animal Behaviour, 71(5), 1227-1237.

Huchard, E., Alvergne, A., Féjan, D., Knapp, L. A., Cowlishaw, G., & Raymond, M. (In press). More than friends? Behavioural and genetic aspects of heterosexual associations in wild chacma baboons. Behavioral Ecology and Sociobiology.

Palombit, R. A., Cheney, D. L., & Seyfarth, R. M. (2001). Female–female competition for male ‘friends’ in wild chacma baboons (papio cynocephalus ursinus). Animal Behaviour, 61(6), 1159-1171.

Palombit, R. A., Seyfarth, R. M., & Cheney, D. L. (1997). The adaptive value of ‘friendships’ to female baboons: Experimental and observational evidence. Animal Behaviour, 54(3), 599-614.

Silk, J. B. (2002). Using the ‘F’-word in primatology. Behaviour, 139, 421-446.

Smuts, B. B. (1985). Sex and friendship in baboons . New York : Aldine Publishing Co.