Research: Why women get cold more than men

A new, scientific explanation for why women feel the cold more than men, give scientists at the Faculty of Zoology at Tel Aviv University.

As they found, this is a phenomenon that is not «exclusive» to humans, as many male endotherms (birds and mammals) tend to prefer lower temperatures than females.

As the researchers write, «we estimate that males and females feel temperature differently. This is a built-in evolutionary difference between the heat perception systems of the sexes, which relates, inter alia, to the reproductive process and the care of offspring.».

The study was led by Eran Levin and Tali Magori Cohen from the School of Zoology and the Steinhardt Museum of Natural History at Tel Aviv University, Yosef Kiat from the University of Haifa and Hagai Sharon from the University of Haifa.the Shackler School of Medicine, also at Tel Aviv University. The scientific article was published in Global Ecology and Biogeography.

H This new research includes an in-depth statistical and spatial analysis of the distribution of dozens of bird and bat species living in Israel, together with an extensive review of the international literature on the subject. Levin, who, among other things, studies the physiology and behavior of bats, noted in his previous studies that during the breeding season males and females tend to separate, with males living in colder areas.

In addition, a study of the relevant literature reveals many examples of similar phenomena in many species of birds and mammals: In migratory birds, males spend the winter in colder regions than females (note that in birds the separation between the sexes takes place outside the breeding season, since males participate in raising the young). Among many mammals, even in species that live in pairs or mixed groups for all their lives, males prefer shade while females prefer light, or males climb to the tops of mountains while females stay in the valleys.

The scientists then did their own research, examining data collected in Israel over nearly 40 years (1981-2018) on thousands of birds from 13 migratory species from 76 sites and 18 bat species from 53 sites. In total, the survey included over 11,000 birds and bats. The reason birds and bats were preferred is that they fly and are therefore highly agile, so their spatial separations would be clearer.

The findings of this study show that males prefer lower temperatures than females, and this preference leads to a separation between the sexes at certain times during breeding cycles when males and females do not need (and may even annoy) each other.

«Our research has shown that the phenomenon is not unique to humans - among many species of birds and mammals, females prefer a warmer environment than males, and at certain times these preferences cause separation between the two species. Given these findings, and the fact that this phenomenon is widespread, we hypothesize that what we have here is a difference between male and female heat-sensing organisms that has evolved over the course of evolution. The difference is similar in essence to the known differences between the sense of pain experienced by the two sexes and is influenced by differences in the nerve mechanisms responsible for the sensation and also hormone changes between males and females,» Levine said.

H Magory Cohen notes that this difference has a number of evolutionary explanations: First, the separation between males and females reduces competition for resources in the environment, and keeps it away males that can be aggressive and endanger the cubs. In addition, many female mammals must protect their young at a point where they are not yet able to regulate their own body temperature, so they developed a preference for a relatively warm climate.

As the two researchers conclude, the final conclusion is that, as far as humans are concerned, this difference in heat perception is intended to create a distance between the two members of the couple so that each can enjoy a degree of peace and quiet. The phenomenon can also be related to sociological phenomena that have been observed in many animals, and even in humans, in mixed environments: Women tend to have more physical contact with each other, while men keep more distance and avoid contact with each other.