> Honeybee (Apis mellifera) colonies don’t hibernate. In the wild they overwinter in tree cavities that keep at least some of their numbers above 18°C in a wide range of climates, including -40°C winters. But popular understanding of their overwintering behaviour is dominated by observation of their behaviour in thin (19mm) wooden hives. These man-made hives have very different thermal properties compared with their natural habitat of thick-walled (150mm) tree hollows.