American Journal of Physical Anthropology

Graphical Abstract Variation in human functional eccrine sweat gland density in our sample is not explained by childhood climate or genetic similarity. Sweat production appears to be decoupled from functional eccrine density; differences in sweat production are attributable primarily to sweat output per eccrine gland. We hypothesize that phenotypic plasticity in aspects of thermoregulation other than eccrine gland density, including per-gland sweat production, are the primary means through which humans have and continue to adjust sweating capacity in new thermoregulatory environments.