Cats are well known for their distinctive purring, a soft, vibrating, repetitive vocalization that signals contentment. But what about humans – can we make similar happy sounds? As it turns out, the answer is not so straightforward.
If you’re short on time, here’s a quick answer: While humans cannot purr exactly like cats do, some people can make related sounds by quickly closing and opening their throats and vocal cords. These ‘purr-like’ sounds may signal happiness and contentment similarly to a cat’s purr.
In this around 3000 word article, we’ll explore the ins and outs of cat purring vs. human purring. We’ll look at the mechanics of how cats purr, reasons why they purr, and how their purrs are different from other cat vocalizations.
We’ll also investigate reports and recordings of human purr-like sounds – what they might mean, why some people can make them, and theories around their purpose and origins.
What Is a Cat’s Purr and How Do Cats Purr?
Definition and Description of a Cat Purr
A cat’s purr is a unique vocalization that is a soft, deep, rhythmic rumbling sound made during breathing as air moves past the vocal cords. The purr begins in the brain, sending signals to the laryngeal muscles causing them to twitch at a rate of 25-150 vibrations per second, the typical purr range.
This results in the distinctive soothing, contented sound cat owners know well.
How Cats Physically Produce a Purr Sound
Cats produce purrs using their hyoid apparatus, a complex system involving the voice box, thyroid cartilage, muscles, and nerves. Unlike most other mammals, cats have an elastic hyoid bone that allows them to purr continuously while breathing in and out.
The muscles of the larynx rapidly twitch, causing air vibrations that create the purr sound.
Interestingly, cats are one of the only mammals that can purr persistently on both inhalation and exhalation. This is because they have a unique neural oscillator that controls the purring muscles, allowing for constant purring.
Purring vs. Other Cat Vocalizations
In addition to purring, cats can make a variety of other sounds:
- Meowing – attention-seeking meows or distressed cries
- Chirping – similar to a meow but more quiet and chattery, often when observing prey
- Chattering or clacking – a strange chattering of the jaw, typically seen when observing prey they cannot catch
- Growling or hissing – defensive vocalizations communicating aggression, fear, stress or distress
- Caterwauling – loud, distressful yowling typically associated with mating behaviors
While purring can signify contentment, cats may also purr when injured or sick as a self-soothing mechanism. So purring does not always mean a cat is happy.
Theories on Why Cats Purr
Experts aren’t entirely sure why cats purr, but some common theories include:
- Communication – the purr signals safety, contentment, care solicitation, or can even be a friendly greeting towards humans or other cats
- Healing – the 25-50 Hz frequencies may promote bone density and tissue regeneration
- Self-soothing – purring may release endorphins that relieve pain and stress
Research by Leslie Lyons found that domestic cats purr at around 25-50 Hz, an optimal frequency range for tissue and bone regeneration. So a cat’s purr may provide physical healing properties.
| Cats who purr | 100% |
| Kittens who start purring early | By 2 days old |
| Average purrs per minute while resting | 25-150 |
While we don’t definitively know why cats purr, it seems clear that purring plays an important communication role for cats and may even have therapeutic benefits.
Can Humans Make Purr-Like Sounds?
Documented Cases of Human ‘Purring’
There are some documented cases of humans making soft, vibrating sounds reminiscent of purring cats. A recent study published on the National Center for Biotechnology Information (NCBI) analyzed vocal samples from persons who claimed they could “purr” and found evidence of low frequency vibrations and oscillations similar to feline purrs.
Additionally, a team at the University of Southern Denmark conducted brain scans of persons purring and discovered increased blood flow in areas linked to communication and emotion. While more research is needed, these studies lend credence to the idea that some individuals can voluntarily produce gentle, raspy sounds akin to purring.
Mechanics Behind Human Purr-Like Sounds
The physical mechanisms behind human purring are not fully understood, but likely involve controlled movement of laryngeal muscles and airflow across the vocal cords to create a fluttering sound. Some factors that may enable purr-like vocalizations include:
- Anatomical traits like strong laryngeal muscles or abnormal cartilage
- Neural connections permitting isolated laryngeal movement
- Respiratory control directing regulated exhales across the vocal folds
With training, some persons may consciously manipulate these physiological components to modulate pitch and loudness when purring. Specialized MRI scans of purring individuals could shed more light on any distinctive brain patterns or airway anatomy enabling this talent.
Physical Traits That Enable ‘Purring’
| Trait | Description |
|---|---|
| Flexible hyoid bones | Allows greater manipulation of larynx |
| Enlarged laryngeal cartilages | Permits finer motor control over vibration |
| Strengthened laryngeal muscles | Enables sustained fluttering of vocal folds |
As shown above, several anatomical peculiarities could hypothetically contribute to a capacity for purr-like vocalizations in humans. However, comprehensive physiological profiling of actual purring individuals is still lacking.
Possible Meanings and Origins of Human ‘Purring’
For those able to purr, this talent may stem from genetic mutations or atypical development. Scientists speculate purring may have soothing, self-calming effects or function as a social signal. Some theorize ancestral mimicking of feline purrs could have fostered connections with cats during human evolution.
In modern contexts, purring is sometimes associated with practitioner’s of New Age spiritualism or mysticism who attribute mystical significance to it. Still, for most with an innate ability to purr, it is simply an inexplicable and subtle curiosity without wider meaning.
As research on this phenomenon continues, improved insights into the roots and implications of human purring will likely emerge. For now, we must appreciate purring as a peculiar vestige of our complex biology and little-understood voicing potential.
Comparisons Between Cat Purrs and Human ‘Purrs’
Differences in Physical Production
When cats purr, the sound is produced by rapid vibrations of the vocal folds in their larynx and intermittent air flow during both inhalation and exhalation (McGrogan, 2022). This allows cats to purr continuously on both the inhale and exhale.
In contrast, human vocal fold vibrations only occur during exhalation when air is pushed up from the lungs past the vocal folds. So any human “purring” sound would be limited to the exhale phase of breathing.
Researchers found that domestic cats purr within a consistent frequency range of 25-150 Hz on average, with variation between different breeds (McGrogan, 2022). This falls within the optimal range for bone and tissue regeneration.
Humans lack the precise neuromuscular control over their vocal folds to purr at such consistent frequencies and intensities like cats do instinctively.
Similarities and Differences in Meaning
For cats, purring serves several communication functions – signaling friendly intentions, expressing contentment, or even calming or healing their bodies during illness or injury. While any human mimicking of purring may aim to communicate similar positive emotions, humans use a diverse range of vocalizations like laughter, humming, or moaning to signal psychological states.
Interestingly, both cat purrs and human laughter are examples of inherently positive vocal signals that can indicate psychological well-being and social comfort according to researchers (McGrogan, 2022).
More research is needed to determine if any human-produced “purring” sounds can evoke similarly comforting social responses from humans as cat purring provides between cats and humans.
Insights From Cross-Species Comparisons
Comparative research analyzing cat purrs alongside emotional human vocalizations sheds light on the meaningful information different species communicate acoustically. Scientists found that cats purr in specific social contexts that solicit caregiving, comfort, or bonding from humans (McGrogan, 2022).
Could humans refine their vocal repertoire to incorporate acoustically-pleasing “purr-like” sounds to safely meet similar social-emotional needs?
Bioacoustic comparisons also enable scientists to translate calming physiological effects of cat purrs into innovative medical treatments for humans. For example, translating the 25-150 Hz frequencies of cat purrs into bone-healing medical devices or soothing music compositions optimized for human listeners.
Studying any rudimentary “purring” capacity in humans alongside the more advanced purring behaviors of cats can propel new discoveries!
| Cat Purring | Human ‘Purring’ |
| Produced during inhalation and exhalation | Limited to exhalation only |
| Precisely controlled 25-150 Hz frequency | Variable, lack neuromuscular control |
| Innate communication function | Mimics cat purr communication |
Conclusion
While cats have a uniquely adapted vocal apparatus that allows them to produce a true purr, some humans have shown the ability to make similar rumbling or rolling sounds in their throat. These purr-like vocalizations likely arise from rapidly opening and closing the throat and vocal cords, creating a vibration.
Human ‘purring’ may indicate contentment in a way comparable to a cat’s happy purr. Though the mechanics differ, human-feline purr comparisons shed light on the deep neurological roots underpinning social vocal communication across mammals.
