Results of the animal model analyses (which include only those variables identified by the reduced models) of absolute endocranial volume (millilitres). (Model 1: all-ages, model 2: adult-only (ages 3+). We fitted Bayesian MCMC animal models using the software MCMCglmm (see ‘Animal model analyses' section in Material and methods). CI, 95% Bayesian credible intervals; n.a., not applicable. Model 1 intercept gives the value for females at age 0 with mother's location at parturition being intermediate; model 2 intercept gives the value for females with mother's reproductive status as milk/winter.)