Supplementary Material for “Ontogeny of cortisol reaction norms in wild bonobos (Pan paniscus)”

This supplementary file contains additional analyses supporting the main manuscript. ESM 1 evaluates the linearity of the diurnal decline in urinary cortisol by comparing linear, quadratic, and spline functions, including Table S1 (model comparisons) and Figure S1 (fitted diurnal curves). ESM 2 presents Bayesian hierarchical models examining the random-effects structure, including intercept–slope correlations, with full parameter estimates, credible intervals, and model diagnostics (Table S2). These analyses confirm that a linear diurnal term and an uncorrelated random-effects structure are appropriate for the main models.