Why does a rat growl? - briefly
Rats emit a low‑frequency guttural sound when they feel threatened, defend territory, or experience pain, serving as a warning to other individuals. The vocalization results from rapid vibration of the laryngeal muscles and signals aggression or distress to conspecifics.
Why does a rat growl? - in detail
Rats produce a low‑frequency vocalization commonly described as a growl when the laryngeal muscles contract to force air through a narrowed glottis. This sound originates from the same vocal apparatus that generates ultrasonic squeaks, but the airflow and tension differ, resulting in a deeper pitch.
The emission of this vocalization occurs in several distinct situations:
- territorial disputes, where a resident individual signals dominance to an intruder;
- aggressive encounters, serving as an auditory threat before physical contact;
- acute pain or injury, functioning as an alarm to conspecifics;
- heightened fear, especially when escape routes are limited;
- establishment or reinforcement of social hierarchy within a colony.
Acoustically, the growl occupies a frequency band between 200 Hz and 800 Hz, with sound pressure levels that can exceed 70 dB at a distance of 10 cm. Spectrographic analyses reveal a relatively flat harmonic structure compared with the broadband noise of ultrasonic calls.
From a communicative perspective, the growl conveys information about the emitter’s emotional state and intent. Receivers typically respond by either retreating, submitting, or escalating the confrontation, depending on their own status and the context of the interaction. This auditory cue thus integrates with olfactory and tactile signals to coordinate group dynamics.
Research employing electrophysiological recordings and behavioral assays confirms that the neural circuitry underlying growl production involves the periaqueductal gray, the nucleus ambiguus, and motor pathways controlling the laryngeal musculature. Pharmacological inhibition of these regions suppresses the vocalization without affecting other sounds, indicating a specialized control mechanism.
Differentiation from other rat vocalizations is essential for accurate interpretation. While ultrasonic squeaks signal mild distress or social contact, the low‑frequency growl specifically denotes a higher level of arousal associated with threat or discomfort. Recognizing this distinction enhances the reliability of behavioral assessments in laboratory and field studies.