Complex sentence: They can enter a resting hypothermic state to conserve energy but be able to respond to external stimuli, or are even able to reduce their body temperature and enter torpor for hours on end-this reduces their metabolic rate and allows great energy conservation in extreme circumstances.
Split into simpler sentences: They can enter a resting hypothermic state to conserve energy but be able to respond to external stimuli. Or are even able to reduce their body temperature and enter torpor for hours on end-this reduces their metabolic rate and allows great energy conservation in extreme circumstances.