Records of body temperature (A) and locomotor activity (B) of a flying squirrel maintained under a 24-h light-dark cycle with 14 h of light and 10 h of darkness (indicated by open and solid bars attop). Records of body temperature (A) and locomotor activity (B) of a flying squirrel maintained under a 24-h light-dark cycle with 14 h of light and 10 h of darkness (indicated by open and solid bars attop). Data were recorded and are plotted in 6-min bins. Roberto Refinetti Am J Physiol Regul Integr Comp Physiol 1999;277:R1493-R1500 ©1999 by American Physiological Society