In low-food years, edible dormice can hibernate for longer than 11 months.
The animal meant here is the European edible dormouse, or Glis glis, a nocturnal rodent found across much of Europe. It normally hibernates from roughly October to May, with timing varying by climate and location. In unusually poor food years, that dormant period can extend beyond 11 months.
This extreme strategy is linked to the dormouse’s dependence on energy-rich seeds and nuts. In good years, it builds fat reserves and may reproduce; when food is scarce, it can skip reproduction and remain underground for much longer. During hibernation, its body temperature and metabolic rate fall sharply, and breathing may pause for periods of up to an hour.
A common mix-up is treating 11 months as the usual hibernation length. It is an exceptional duration associated with low food availability, not the normal annual schedule. Most edible dormice are active for about six months and typically hibernate for part of the colder season.