Fig. 2.

Representative original tracings of activity readings (bars), metabolic rate (line and scatterplot) and body temperature (line plot) in individual wild-type and UCP1-KO mice during a cold endurance test (∼4 h at 30°C, up to 5 h at 5°C, temperature switch indicated with an arrow). Previously WA mice of either genotype had to be removed from the experiment because of hypothermia (final body temperature <31°C). In contrast, the mice acclimated to MCA (18°C) remained normothermic. Note the reduced activity and the less variable metabolic rates of the WA wild-type (WT) mouse and the two UCP1-KO mice.