When reproductive status is not an issue, physiologists generally study the characteristics of male members of a species. Seldom does one find thorough analyses of the influence of either gender or genetic strain (i.e., intraspecies variation) on thermoregulation or other regulatory systems. Moreover, one occasionally finds that males and females have been used interchangeably in a study with no regard to the possibility of sexual differences. Likewise, the genetic strain often is not considered as a significant factor in a study. Such omission is neither intentional nor the result of ignorance. Generally, as is the case in thermal physiology and other fields, there is so little information on the impact of gender and genetic strain that it is impossible to consider these factors in interpreting the data. Hence, this chapter is intended to provide a review of the effects of gender and genetic strain on thermoregulatory responses in rodents. It is hoped that an analysis of the meager data base in this area will spur more research in the areas of gender and strain differences in thermal physiology.

Gender differences

Considering the obvious morphological and physiological variations of male and female rodents, one should not be surprised to find gender-specific thermoregulatory differences. The action of steroid sex hormones (i.e., androgens and estrogens) can impact in various ways on thermoregulatory processes. It was discussed earlier (Chapter 6) how females undergo marked changes in thermoregulatory sensitivity during pregnancy and lactation.