*Review* **Biological and Acoustic Sex Differences in Rat Ultrasonic Vocalization**

**Charles Lenell 1,2 , Courtney K. Broadfoot 1,3, Nicole E. Schaen-Heacock 1,3 and Michelle R. Ciucci 1,3,\***


**Abstract:** The rat model is a useful tool for understanding peripheral and central mechanisms of laryngeal biology. Rats produce ultrasonic vocalizations (USVs) that have communicative intent and are altered by experimental conditions such as social environment, stress, diet, drugs, age, and neurological diseases, validating the rat model's utility for studying communication and related deficits. Sex differences are apparent in both the rat larynx and USV acoustics and are differentially affected by experimental conditions. Therefore, the purpose of this review paper is to highlight the known sex differences in rat USV production, acoustics, and laryngeal biology detailed in the literature across the lifespan.

**Keywords:** ultrasonic vocalization; larynx; female; male; sex differences
