The tremendous volume of scientific research on thermobiology, prompted partly no doubt by man's own inefficient, subjective performance as a thermometer, bears witness to the ultimate utter dependence of all organisms on solar radiation. It is well known that the adaptation of animals to thermal factors is unequal and varied, and that this is demonstrated by the way in which temperature may act as a limiting factor, either alone or as one environmental component interacting with others. Clearly, a consideration of the broader ecological implications of temperature is germane to an understanding of the formation, evolution and interrelation of faunal aggregations in the biosphere. Keywords: Climatic circumstances, Faunal discontinuities, Glacial phase, Huddling, Isolines, Isonomaly, Metabolic rates, microhabitats, nest-making, Pleistocene, thermal gradient.