Presentation Information
[P3-39]Vocal timing and social affiliation: A comparative study in rats of same and different strains.
*Miki Kamatani¹,²,³, Shiomi Hakataya³,⁴, Genta Toya⁵, Shinya Yamamoto¹, Kazuo Okanoya²,⁶ (¹Kyoto University, ²Teikyo University, ³Research Fellow, Japan Society for the Promotion of Science, ⁴University of the Ryukyus, ⁵Institute of Science Tokyo, ⁶The University of Tokyo)
Keywords:
rats,emotional vocalizations,ultrasonic,turn-taking
Social animals form close and enduring relationships with others, and such affiliative bonds confer adaptive advantages, including increased reproductive success and reduced stress. However, given the demands of resting and foraging essential for survival, the time available for social interaction is limited. It is therefore assumed that social animals may adopt strategies to minimize the time cost of establishing affiliative relationships—such as preferentially engaging with similar individuals upon first encounter. This study focused on rats, a highly social species that can form colonies exceeding 150 individuals and are known to maintain social networks that favor specific partners. Prior research suggests that rats may prefer individuals of the same strain in their social networks. However, little is known about how social interactions differ within versus between strains. The goal of this study is to elucidate the mechanisms underlying affiliative relationship formation by comparing social interactions between unfamiliar rats of the same and different strains. We used Sprague-Dawley and Long-Evans rats and recorded their behavior and vocalizations under free-ranging conditions. Specifically, we analyzed the number and timing of ultrasonic vocalizations (USVs): 50 kHz USVs, which are typically associated with positive affect, and 22 kHz USVs, which occur in negative or aversive contexts. Our primary hypothesis is that rats will emit more 50 kHz USVs—and show more immediate vocal responses to their partner's calls—during interactions within the same strain compared to interactions between strains, reflecting a preference for socially similar individuals (Work supported by JSPS 23H05428 to KO and JSPS 24KJ0124 to MK).