Fig. 2. The probability of occurrence for 31 chimpanzee behaviours per community as a function of environmental variability.

These behaviours are more likely to occur when chimpanzees live in habitats a further away from Pleistocene forest refugia, with b greater precipitation seasonality, and c a predominantly savannah woodland landscape. The size of the circles in plots a and b indicates the sample size, or number of chimpanzee communities per value of the predictor where the total n = 144 chimpanzee communities. The coloured areas depict the 67, 87, and 97% credible intervals centred on the mean predicted posterior distribution (a, b dashed line, c horizontal line) for the probability of occurrence across all 31 behaviours.