What are hibernation and torpor in animals?

Hibernation and torpor describe states in which some animals reduce metabolism and body temperature to save energy.

Duration and physiology

Torpor may be brief, whereas hibernation can span longer periods depending on conditions. Body temperature, heart rate and arousal patterns differ greatly across species. Not every animal sleeps continuously all winter. The winter state of bears and deep hibernation in small mammals do not follow identical physiology. Food shortage, day length and temperature may influence these states.

Ecological meaning

Energy use falls when food is scarce, but animals need stored reserves and safe shelter. Damaged shelter or frequent disturbance can cause costly arousals. Rather than touching or feeding an inactive wild animal in winter, it is better to consult local wildlife experts. The terms should not be applied to every motionless animal.