Ultrasonic Vocalizations and Affective Communication in Rodents

Rodents emit a rich repertoire of ultrasonic vocalizations that serve as windows into their emotional states and social interactions. These high-frequency signals, imperceptible to the human ear without specialised equipment, span distinct frequency bands associated with aversive or appetitive contexts. Long, low-frequency calls (around 22 kHz) accompany negative states such as fear, pain or social alarm, whereas brief, high-frequency calls (around 50 kHz) coincide with positive experiences including play, reward anticipation and social bonding. Beyond simple indicators of internal affect, ultrasonic vocalizations can function as communicative signals that modulate the behaviour of conspecifics, promoting social cohesion, emotional contagion or avoidance. Recent advances in acoustic analysis, playback paradigms and neural recording have deepened our understanding of the production mechanisms, perceptual processing and neural circuits underlying these vocal behaviours. Together, these studies underline the value of rodent vocalisations as translational models for exploring the neurobiology of emotion, the development of social cognition and potential interventions for affective disorders.

Research from Nature Portfolio

Recent studies have demonstrated that rodents’ own audible pain squeaks can enhance freezing and low-frequency vocal responses in observers, indicating a form of emotional contagion. Pre-exposure to footshock not only heightened distress calls during playback but also revealed that decoupling self-produced pain squeaks from shock impedes sensory-driven fear contagion. These findings highlight the importance of self-generated vocal feedback in the development of social transmission of distress and suggest that auditory cues alone can shape empathic responses in rodents.

Ultrasonic Vocalizations and Affective Communication in Rodents publication trend

The graph below shows the total number of articles in ultrasonic vocalizations and affective communication in rodents across all publications each year (not limited to Nature Index journals).

Technical terms

Ultrasonic vocalization (USV): High-frequency calls above 20 kHz emitted by rodents to signal internal states and influence conspecific behaviour.

22-kHz call: Long, low-frequency vocalization associated with negative affective states such as fear, distress or threat signalling.

50-kHz call: Short, high-frequency vocalization often frequency-modulated and linked to positive states like reward, play and social approach.

Emotional contagion: The process by which one individual’s emotional state induces a similar state in an observer, often via social cues.

Acoustic playback: Experimental presentation of recorded vocalizations to study receivers’ behavioural and physiological responses.

References

1. Male rats emit aversive 44-kHz ultrasonic vocalizations during prolonged Pavlovian fear conditioning. eLife (2024).
2. Adult rat ultrasonic vocalizations and reward: Effects of propranolol and repeated cocaine administration. Journal of Psychopharmacology (2024).
3. Audible pain squeaks can mediate emotional contagion across pre-exposed rats with a potential effect of auto-conditioning. Communications Biology (2023).