The difference in heat preferences for males and females comes from an evolutionary phenomenon designed to keep males and females apart when they do not need each other, a study finds.
The study, which was published in Global Ecology and Biogeography, sought to discover why women prefer warmer temperatures while men are more comfortable in cooler temperatures.
In order to understand temperature preference differences between women and men, the researchers studied the habits of dozens of species of birds and bats. They found that bats segregated during the weening season, with males preferring cold temperatures like caves on the Hermon, and females preferring to stay in the warmer climates of the valleys.
Birds, on the other hand, were found to segregate outside of breeding and weening seasons because the males help take care of the chicks. As with the bats, the males segregated themselves to cooler climates while females went to warmer climates.
The research was led by Dr. Eran Levin and Dr. Tali Magory Cohen from the School of Zoology at Tel Aviv University, Yosef Kiat from the University of Haifa and Dr. Haggai Sharon of Tel Aviv University's Sackler Faculty of Medicine.
The research team specifically chose bats and birds because their flying abilities make them highly mobile, and the scientists believed that this would make segregation results clearer. Furthermore, the climate diversity in Israel provided the team with a diverse study of different climatic conditions.
The study concluded that segregation keeps the males and females apart at periods when they do not need each other, which lessens the competition for resources and the chances of conflict between the sexes.
"Our study has shown that the phenomenon is not unique to humans," Levin said. "Among many species of birds and mammals, females prefer a warmer environment than males, and at certain times, these preferences cause segregation between the two genders.
"In light of the findings and the fact that this is a widespread phenomenon, we have hypothesized that what we are dealing with is a difference between the females' and males' heat-sensing mechanisms, which developed over the course of evolution," he said. "This difference is similar in essence to the known difference between the pain sensations experienced by the two sexes, and is impacted by differences in the neural mechanisms responsible for the sensation and also by hormonal differences between males and females.
"The bottom line, going back to the human realm, is that we can say that this difference in thermal sensation did not come about so that we would argue with our partners over the air-conditioning, but rather the opposite," Levin and Cohen said. "It is meant to make couples take some distance from each other so that each individual can enjoy some peace and quiet.
"The phenomenon can also be linked to sociological phenomena observed in many animals and even in humans," they concluded. "In a mixed environment of females and males, females tend to have much more physical contact between themselves, whereas males maintain more distance and shy away from contact with each other."