Female mice prefer warmer surroundings than male mice, and a new study suggests that testosterone helps shape this difference by altering how heat- and cold-sensing proteins in the skin influence temperature preference. The researchers found that female mice preferred surfaces averaging about 96.8 degrees Fahrenheit (36 degrees Celsius), compared with approximately 89.6 F (32 C) for males—a difference of about 7 F (4 C).
The study, published on October 28 in a physiology journal, offers clues about how sex differences in temperature perception arise. The findings could eventually help researchers understand conditions such as neuropathic pain, in which sensitivity to heat and cold can increase. However, the work was conducted in mice and has not been tested in humans.
How mice choose a temperature
The skin contains proteins in nerve endings that respond to warmth and cold. When activated, these proteins allow charged ions to enter sensory neurons, generating electrical signals that travel to the brain. The connections made by those neurons help determine whether an organism perceives an environment as hot or cold, said Dr. Michael Caterina, a neuroscientist at Johns Hopkins University who was not involved in the study.
Females of several species, including mice and birds, appear to prefer slightly warmer temperatures than males. To investigate the difference, researchers placed 30 male mice and 27 female mice in an enclosure with two adjacent plates.
One plate was kept at 91.4 F (33 C), while the temperature of the second plate varied from cooler to warmer conditions. A camera tracked the mice and calculated how much time each animal spent on each surface.
Both male and female mice spent more time on the 91.4 F plate when the other plate was cooler. But when the second plate was heated to 100.4 F (38 C), females spent significantly more time on the warmer surface than males.
The researchers also measured the animals’ internal and skin temperatures and found no significant differences between the sexes. “Because the top of the cage was completely open, there was no question that temperature affected the mice,” said study co-author Peter McNaughton, a pharmacologist at King’s College London who studies pain, thermal sensation and temperature regulation. This meant the differences in preference were determined by the mice’s temperature-sensing systems rather than by differences in their body or skin temperatures.
The role of temperature-sensing proteins
The researchers genetically deleted a protein that detects warmth. In male mice, this reduced their avoidance of the warm plate, suggesting that the protein normally sends a signal that discourages them from staying on hot surfaces. The males’ preferred body temperature rose to about 95 F (35 C), approaching the preference observed in females.
Deleting or blocking the same protein in female mice had no significant effect. The researchers also eliminated or blocked proteins that detect cold. Afterward, males and females were less likely to avoid the cold plates. Female mice spent less time on the warm plates, while the males’ preference for those plates remained unchanged.
“Females are a little more responsive to cold receptor activation, but a little less responsive to warm receptor activation,” Caterina said. The researchers observed this difference even though the temperature-sensing neurons in male and female mice otherwise functioned similarly.
These results led the team to examine whether sex hormones could explain the different responses.
Testosterone appears to influence temperature preference
Male mice were given a drug that inhibits testosterone production. Several weeks later, the treated males spent more time on plates heated to 38 C than males with normal testosterone levels. Female mice given testosterone, by contrast, lost some of their preference for warmer temperatures.
Adding female hormones, including estrogen and progesterone, to the diets of male mice did not change their temperature preferences. Blocking those hormones in female mice also had no effect, even though estrogen and progesterone are known to influence other aspects of thermoregulation.
“So testosterone seems to be the most important determinant,” McNaughton said. But the effect was only partial: testosterone did not completely eliminate the difference between male and female mice. “That means there’s something else going on that we haven’t been able to identify,” he added.
The precise mechanism remains unclear. Because the effects emerged over several weeks, the researchers suggested that testosterone may not act directly on the temperature-sensing proteins. Instead, it could influence their activity indirectly by changing gene activity. Further research will be needed to test that possibility.
Possible relevance to humans
The study’s authors have not tested the mechanism in humans, but McNaughton noted that the same sensor protein is present in people. Research in humans suggests that people may show similar patterns in their temperature-related behavior.
“I would say this is just a cute observation, not particularly important,” McNaughton said. “[But] it has practical implications.”
Caterina called the study “valuable information” for understanding how temperature-sensing proteins work. “What kind of signals create our everyday experience of temperature is itself very important,” he told Live Science. “It’s an important part of understanding ourselves as living things.”
This article is for informational purposes only and does not provide medical advice.
Vilar, B., McNaughton, P. A. (2026). “TRPM8 and TRPM2 ion channels determine sex differences in thermopreference in mice.” physiology journal.
Source: www.livescience.com