A Mammalian Activity Rhythm independent of Temperature

ONE of the most important characteristics of biological rhythms is their independence of temperature. Even the mammal may display a wide range of body temperatures, so that any hypothetical biochemical clock that it may possess may be ‘challenged’ to measure time at low temperatures. Some mammals have a wide range of body temperature both in a warm environment and while going into hibernation. Furthermore, with hypothermia as a procedure in human surgery, even human subjects undergo large changes in body temperature. Thus, measurements of rhythms in the cold mammal are of increasing interest. The following preliminary notes suggest the independence of temperature of a mammalian activity rhythm.