Table 1.

Negative binomial regression model linking reproductive success and male-infant affiliation.

Predictor	Coef+/−SE	Z	P	95% CI
Affiliation	10.07+/−0.73	13.74	0.000	8.64, 11.51
Age at behavioral data collection	−0.10+/−0.02	−5.09	0.000	−0.14, −0.06
Age when exited dataset	−0.01+/−0.02	−0.55	0.579	−0.05, 0.03
Rank at behavioral data collection (reference = alpha)
Beta	−0.85+/−0.12	−6.88	0.000	−1.09, −0.61
Gamma	−1.54+/−0.39	−3.9	0.000	−2.31, −0.76
Subordinate	−3.03+/−0.47	−6.41	0.000	−3.95, −2.10
Highest lifetime rank achieved (reference = alpha)
Beta	1.36+/−0.12	11.65	0.000	1.13, 1.59
Gamma	−0.77+/−0.25	−3.12	0.002	−1.26, −0.29
Subordinate	−20.97+/−0.75	−27.92	0.000	−22.44, −19.50
Constant	1.42+/−0.92	1.54	0.123	−0.38, 3.22

n = 23 males, 109 infants; pseudo R squared = 0.482. Outcome variable is the total number of known infants males sired by 2014. Affiliation predictor is a composite measure of the time males spent grooming and resting in contact with all available infants during behavioral data collection in 2003–04. Relevant age and dominance rank variables are included as controls, along with reproductive opportunity as an exposure variable. Results confirm previously established relationships among male rank, age, and reproductive success in the study population.