How do cats purr?
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Understanding How Cats Purr
Mechanism of Cat Purring: Laryngeal Modulation
Cats purr through a mechanism primarily driven by the larynx, which modulates respiratory flow to produce the characteristic sound and vibration. This process does not require the diaphragm or other muscles beyond those necessary for respiration. The frequency of purring in domestic cats is typically around 26 Hz, with slight variations between inspiration and expiration phases. This laryngeal modulation is consistent across different ages and can occur simultaneously with other vocalizations.
Purring Frequencies and Their Effects
The frequencies at which cats purr, ranging from 25 to 150 Hz, have been linked to various health benefits. These frequencies correspond to those used in therapeutic treatments for bone growth, pain relief, and muscle healing. Specifically, domestic cats and other felids like servals and pumas produce strong frequencies at 25 Hz and 50 Hz, which are optimal for promoting bone growth and healing fractures.
Purring as a Communication Tool
Cats also use purring as a subtle form of communication, particularly to solicit food from humans. When seeking food, cats embed a high-frequency component within their purr, which resembles a cry or meow. This component makes the purr sound more urgent and less pleasant, effectively exploiting human sensory biases towards nurturing behaviors. This solicitation purr is perceived as more urgent by humans, even those without prior experience with cats.
Interrupting Purring During Veterinary Examinations
Purring can pose challenges during veterinary examinations, particularly during auscultation. Studies have shown that certain interventions can effectively stop cats from purring, allowing for better examination. The most effective method is placing the cat near a running tap, which stops purring in 81% of cases. Other methods include using an ethanol-based aerosol near the cat (50% effectiveness) and blowing gently into the cat's ear (13% effectiveness) .
Conclusion
Cats purr through a centrally driven laryngeal modulation of respiratory flow, producing frequencies that have therapeutic benefits. Purring also serves as a communication tool, particularly for soliciting food from humans. During veterinary examinations, specific interventions can effectively stop purring, facilitating better auscultation. Understanding these mechanisms and their implications can enhance our interactions with and care for domestic cats.
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