How does a mouse grunt? - briefly
Mice emit a brief, low‑frequency sound by rapidly vibrating their vocal folds as air is expelled, creating a short, guttural grunt. The noise results from rapid laryngeal muscle contraction during brief exhalation bursts.
How does a mouse grunt? - in detail
Mice produce low‑frequency vocalizations by forcing air through the laryngeal passage while the vocal folds vibrate. The sound originates in the trachea, where the diaphragm and intercostal muscles generate a rapid expiratory airflow. When the airflow reaches the glottis, the vocal folds close partially, creating a pressure differential that induces oscillation. This oscillation emits a short, broadband grunt lasting 10–30 ms, with dominant frequencies between 300 and 800 Hz.
The acoustic pattern varies with the animal’s physiological state. In aggressive encounters, the grunt amplitude rises and the pulse frequency shortens, reflecting heightened muscular tension. During mild stress, the sound remains softer, with longer intervals between pulses. Social interactions often involve a series of grunts spaced by 100–200 ms, allowing the receiver to extract information about the sender’s size and emotional condition.
Key anatomical components involved in the production include:
- Laryngeal cartilages that shape the glottal aperture.
- Intrinsic laryngeal muscles that adjust vocal fold tension.
- Respiratory muscles that regulate subglottal pressure.
- Neural circuits in the brainstem that coordinate timing and intensity.
Experimental recordings show that the grunt spectrum contains harmonics up to 4 kHz, but the fundamental frequency carries the most behavioral relevance. Electro‑myographic studies confirm that activation of the thyroarytenoid and cricothyroid muscles precedes each grunt, indicating precise motor control.
Overall, the grunt results from coordinated respiratory effort, laryngeal vibration, and neural timing, producing a distinctive acoustic signal used for communication and threat display.