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2,3,5‐trimethyl‐3‐thiazoline (TMT) is a chemical compound extracted from red fox urine and can be used to artificially simulate the presence of a predator. The purpose of this study was to test the hypothesis that TMT would block entry into torpor in the lab mouse. We first demonstrated that TMT induces fear in the mouse. Exposure to TMT induced a freeze response (67.2 ± 6.7% of time without movement over 10 minutes), as compared to 6.7 ± 1.7% without movement when exposed to water. When fed mice were exposed to TMT during the dark or light phase, body temperature dropped by 1.4 ± 0.2°C and 1.0 ± 0.2°C, respectively, over the first hour after exposure. Exposure to TMT for 30 minutes increased circulating corticosterone, 377 ± 33 ng/ml, as compared to 29 ± 4 ng/ml when exposed to water. To determine whether TMT influences daily torpor, mice were calorically restricted and exposed to either water or TMT. Mice were exposed one hour before the start of torpor, determined by the bout of the previous day. Exposure to TMT blunted torpor by increasing the minimum body temperature from 29.2 ± 0.3°C (water) to 30.1 ± 0.6°C (TMT) and by decreasing the amount of time the mice spent under 32°C from 431 ± 48 minutes (water) to 292 ± 78 minutes (TMT). These results establish that mice perceived the scent of TMT as a physiologically stressful stimulus and that torpor is blunted but not blocked in the presence of that stressor.