Table 2.

Linear mixed models predicting variation in gut microbial alpha diversity in baboons (n = 178 samples from 78 individuals)

	Fixed Effects	Estimate	Standard Error	z	P	Direction of Effect
Core
OTU richness	Social group	0.556	0.169	3.29	0.001	Viola’s > Mica’s
	Age	0.0226	0.0167	1.36	0.18	—
Shannon’s H	Social group	0.221	0.0769	2.87	0.004	Viola’s > Mica’s
	Age	0.0334	0.0077	4.34	<0.001	older > younger
Faith’s PD	Social group	0.224	0.062	3.62	<0.001	Viola’s > Mica’s
	Age	0.014	0.006	2.28	0.022	older > younger
Non-core
OTU richness	Social group	227.8	48.86	4.66	<0.001	Viola’s > Mica’s
	Age	14.8	4.84	3.05	0.002	older > younger
Shannon’s H	Social group	0.0911	0.127	0.72	0.47	—
	Age	0.0326	0.0125	2.60	0.009	older > younger
Faith’s PD	Social group	0.864	1.019	0.85	0.4	—
	Age	0.344	0.101	3.39	<0.001	older > younger

Note: Models show fixed effects that were significant in at least one model. We also tested sex and grooming partner diversity as fixed effects, but these factors were never significant. Kinship between baboons was modeled as a random effect.