Fig 2. Differences in hair cortisol concentrations between seasons and chimpanzee communities with diverse anthropogenic impacts.

Residualized mean hair cortisol concentrations (accounting for nest age effect) with 95% CI in different chimpanzee groups and seasons. (a) Chimpanzees did not exhibit significantly more cortisol due to tourism or logging in comparison to the control group without human contacts. A significant effect of seasonality [F(2,129) = 37.4, p < 0.0001, r² = 0.18] was presumably unrelated to human impacts. (b) The comparison of hair cortisol concentration between chimpanzees living in an intact forest and those in a forest fragment with severe human-wildlife conflicts revealed significantly elevated HCC in the latter group [F(1,88) = 5.0, p = 0.03, r² = 0.20].