Table 5.

Social bond strength was adjusted for the following covariates

Covariate	Definition	Rationale
Group density	Mean number of adult members in the subject’s social group during the year in which bond strength was calculated	Females who live with different numbers of potential social partners may exhibit different bond strengths.
Mean number of coresident adult maternal relatives (R > 0.25)*	Mean number of adult maternal sisters, adult daughters, and mother living in the same social group as the subject during the year in which bond strength was calculated	For female baboons, maternal kin may offer additional support, beyond the scope of social bonds, which could be relevant to fGC concentrations (e.g., physical protection) (69, 70). Controlling for number of relatives is a conservative approach that helps isolate the effects of bonds per se, because animals with smaller matrilines may receive less kin support.
Percent of prior year with young infant*	Percent of days in the year that a female had an infant less than 3 mo old	Adult females are attracted to other females' young infants (86, 87), so females with young infants may have stronger social bonds with other females.
Percent of prior year cycling†	Percent of days in the year that a female was cycling	Males socialize more with females who are cycling (88, 89), so females who cycled for a larger fraction of the year may have stronger social bonds to males.

^*Used only in models where the mediator was social bonds with females.

^†Used only in models where the mediator was social bonds with males.