Definition of the Climatic Niche limits for Homo species
For each hominin species, we built a climatic envelope. We pooled together all bioclimatic values associated to their fossil occurrences. Then, we selected the recorded minimum values for MinTemp, MinPrec, and NPP, and the maximum values for MaxTemp, MaxPrec, and NPP. We repeated this procedure over 100 replicates. At each replication, the age of each individual archaeological locality was sampled at random from the uniform distribution spanning from the estimated minimum to the maximum locality age. Thus, replication accounts for both ageing uncertainty of individual archaeological layers and, correspondingly, for climatic uncertainty around the paleoclimatic estimates concerning the fossil localities. Finally, for each bioclimatic variable, we took the mean value from each resulting distribution of temperature, precipitation and NPP minima and maxima. Taken together, these mean values of bioclimatic extremes represent a conservative estimate of the climatic range realized for each hominin species during its history, avoiding putting too much faith on extreme values attached to individual replicates and locality.