Fig. 4. (A) Minimal resting metabolism (diamonds, 5 min averages; open circles, 30 min averages), average daily energy use (squares), and highest oxygen consumption (filled circles; 1 min average) at three ambient temperatures. The solid diamond in the upper left indicates the maximal _O2 (1 min average) during forced treadmill exercise at room temperature. Values are means ± S.D. (for N, see text). (B) Averaged least-squares regression lines for animals of standard mass (22.2 g) for the relationship between running speed and oxygen consumption. The rightmost end of each regression line indicates the mean maximum instantaneous running speed for that temperature and the circle indicates the mean maximum 1 min average (neither was significantly affected by temperature). Arrows indicate the estimated _O2 at the highest attained instantaneous running speed of about 5 km h^-1.