Disruption of Hibernation Caused by Hypothalamic Lesions

Abstract

Lesions were made in the preoptic-anterior hypothalamic area or ventromedial nucleus of ground squirrels (Citellus tridecemlineatus). Four squirrels, two with preoptic damage and two obese hyperphagics, entered hibernation within 1 to 3 days. They all died after 11 to 12 days, shortly after all normal hibernating squirrels had awakened. Seven squirrels with preoptic damage, rendered hypothermic before being placed in the cold, died within 2 to 6 days.