How cats purr

Sissom, Rice and Peters investigated the long-debated mechanism of purring by recording the sound and associated body vibrations in domestic cats. They documented that purring is produced continuously during both inhalation and exhalation, a near-unbroken sound generated by rhythmic activity rather than passive airflow, and they characterized its acoustic properties including the low fundamental frequency. Their measurements supported the model in which intrinsic laryngeal muscles open and close the glottis cyclically, modulating airflow to create the purr, with the central nervous system driving the rhythm. The work helped establish purring as an actively produced vocalization distinct from other cat sounds and provided quantitative description that later studies built on when probing the neural control and possible functions of this characteristic feline behaviour.