Memory on ice: spatial memory is retained over a 9-month hibernation period in Columbian ground squirrels

Abstract

Abstract Memory allows animals to utilize ecologically relevant information, yet whether it endures through prolonged metabolic shutdown is poorly understood. We tested spatial memory retention in a long-term, free-living hibernator, the Columbian ground squirrel (Urocitellus columbianus), using a field-based spatial maze over two consecutive active seasons. Ten individuals were tested before and after a 9-month hibernation period and compared with eight naive individuals. Maze-solving performances—time to exit, path sinuosity and navigational errors—were analysed over 10 consecutive trials using Bayesian nonlinear learning curves to separate retained memory from relearning. Strikingly, post-hibernation individuals with prior exposure to the task significantly outperformed naive individuals by 41–98% across all metrics, with initial performance after hibernation approaching pre-hibernation asymptotes. We show that spatial memory survives prolonged hibernation in the wild, supporting the hypothesis that neural plasticity during hibernation reflects adaptive retention rather than memory loss.