Why do cats vibrate when they purr? - briefly
Cats vibrate when they purr due to rhythmic contractions of the laryngeal and diaphragmatic muscles during exhalation. This mechanical process creates a unique sound that is often associated with contentment or happiness in felines.
Why do cats vibrate when they purr? - in detail
Cats produce their distinctive purring sound through a complex interplay of muscle contractions and airflow in the larynx, which results in a low-frequency vibration. This vibration is not merely an auditory phenomenon but also involves physical oscillations that can be felt when a cat is purring.
The mechanism behind this vibration begins with the brain sending signals to the muscles in the larynx, specifically the thyroarytenoid muscle, which controls the vocal cords. As these muscles contract rapidly, they cause the vocal cords to vibrate at a frequency of about 25-150 Hz. This low-frequency vibration is what we perceive as purring.
In addition to the laryngeal contractions, cats also use their diaphragm and abdominal muscles during purring. The coordinated action of these muscle groups helps to maintain a steady airflow through the vocal cords, ensuring that the vibration is continuous and consistent. This muscular activity not only produces the sound but also generates a physical sensation that can be felt by touching the cat's throat or chest area.
Interestingly, cats can purr even when they are not inhaling or exhaling, which suggests that they have some control over the process separate from their normal breathing cycle. This unique ability allows them to produce a continuous purring sound without interruption, further enhancing the soothing and comforting effect of their purrs on both themselves and those around them.
In conclusion, cats vibrate when they purr due to the rhythmic contractions of the muscles in their larynx and the coordinated action of their diaphragm and abdominal muscles. This complex physiological process results in a low-frequency vibration that is both audible and tangible, contributing to the distinctive and comforting nature of a cat's purr.