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. 2020 Apr 16;223(8):jeb218479. doi: 10.1242/jeb.218479

Fig. 1.

Fig. 1.

Predator odor induces a rapid rise in skeletal muscle thermogenesis. (A) Gastrocnemius temperature was significantly elevated after predator odor compared with control exposure in male rats (n=8). (B) Gastrocnemius temperature elevation was rapid, being detectable at 2 min after exposure (n=4). (C) Predator odor-induced thermogenesis was evident when activity levels were controlled using treadmill walking (n=7). *Predator odor>control. (D,E) Novel or aversive odors did not significantly change muscle temperature (D), and the temperature change induced by fox odor or by handling and restraint stress was significantly less than that induced by ferret odor (E; area under the curve, AUC; n=7). *Effect>control; ‡ferret odor>all other groups. (F,G) Female rats showed similar muscle thermogenic induction, and neither control nor predator odor-stimulated thermogenesis (F) or temperature AUC (G) differed between proestrus and diestrus phases of the estrous cycle (n=5). *Predator odor>control. (H,I) Predator odor-induced increases in muscle temperature (H) and temperature AUC (I) were also seen in mice up to 60 min after exposure (n=3 male+3 female). *Predator odor>control; ‡significant interaction.