Exposure to odors from stressed conspecifics increases preference for higher ambient temperatures in C57BL/6J mice

Exposure to odors from stressed conspecifics increases preference for higher ambient temperatures in C57BL/6J mice. C57BL/6J male mice were individually allowed preferences on a thermal gradient ranging in temperature from 22°C to 42°C. Group 1 (N=10) was exposed to odors from triads of foot-shocked conspecifics during the first 2-hr temperature preference trial. Group 2 (N=10) was exposed to odors from triads of nonstressed conspecifics during similar testing. Body temperature (T_B) variations were measured in three animals of each group. Thermal preference was significantly higher for animals exposed to odors from stressed conspecifics than for animals exposed to odors from nonstressed animals (32.0°C vs. 29.0°C). T_B changes on the heated gradient were significantly higher for animals exposed to odors from stressed animals (+1.5°C) than for animals exposed to odors from nonstressed animals (-0.33°C). Additional animals on a non-heated thermogradient were tested for T_B when exposed to odors from stressed or from nonstressed animals (N=3 per condition). There was no difference in T_B between these two groups. Increases in T_B on the heated gradient are apparently due to the higher ambient temperature choices and not due to the odor per se.