overwintering

thumb|Migration of cranes Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activity or even survival difficult or near impossible. In some cases "winter" is characterized not necessarily by cold but by dry conditions; passing through such periods could likewise be called overwintering.

Hibernation and migration are the two major ways in which overwintering is accomplished. Animals may also go into a state of reduced physiological activity known as torpor.