Fig. 5. Time series of infrared thermograms from one squirrel (T_a=22°C) during normoxia (30 min), hypoxia (60 min) and normoxic recovery (30 min). Images represent pictures taken at approximately 2 min intervals (eight images correspond to 30 min duration). Note the feet and ears warming up during the early period of hypoxic exposure, and the lack of peripheral warming during the recovery period of intense metabolic activity.