Divergent behavioral strategies in Wistar and Wistar-Kyoto rats in a naturalistic task reveal mood disorder phenotypes

Rodent models are essential for studying mood disorders, yet many assays rely on methods that may not reflect natural behavior. Food hoarding offers an ethologically relevant paradigm integrating reward seeking, risk assessment, and safety-seeking strategies. We assessed hoarding in Wistar-Kyoto (Kyoto) rats, a model of depression and anxiety, compared with Wistar controls. Kyoto rats, particularly females, displayed robust hoarding, frequently transporting all food items to the safe base while consuming little. In contrast, Wistars consumed more and showed greater exploratory activity, moving at higher velocity. Principal component analysis and k-means clustering identified distinct behavioral phenotypes, with Kyotos clustered into high hoarding, low exploratory profiles consistent with anxiety- or depressive-like profiles, while Wistars clustered into more exploratory phenotypes. Pose estimation revealed reduced locomotor velocity in Kyoto rats compared with Wistar controls, consistent with altered risk assessment. Overall, this task captures strain- and individual-level variation in mood-related behavior under more naturalistic conditions.