Most people can hear at least some of the sound a dog whistle produces, especially if the whistle is adjustable and set toward the lower end of its range. Dog whistles are often called “silent,” but that label is misleading. These devices typically emit frequencies anywhere from about 16 kHz to 54 kHz, and the human ear can detect airborne sounds up to roughly 20 kHz under ideal conditions. Whether you personally hear anything depends on the whistle’s setting, your age, and the health of the delicate structures in your inner ear.
What a Dog Whistle Actually Produces
The original “silent” whistle was invented in 1876 by Francis Galton, who was trying to determine the upper limit of hearing across different species. He designed a small adjustable tube that could produce very high-pitched tones, and he tested it on humans, dogs, cats, and other animals. His insight was that different species stop hearing at different frequencies, and the whistle that now bears his name was built to exploit that gap.1PubMed. The Galton whistle and discovery of presbycusis
Modern dog whistles work on the same principle. Most are adjustable, letting the user slide between frequencies. At the low end, around 16 to 18 kHz, many humans can hear a sharp, thin, somewhat piercing tone. At the high end, above 22 or 23 kHz, the sound sits well beyond what any human ear can pick up. Dog trainers often settle on a frequency in the 23 to 35 kHz range so the whistle carries well for the dog without being conspicuous to bystanders. But “silent to humans” really means “silent to most adult humans at certain settings.” A child standing nearby might hear the whistle perfectly well, and even some adults catch a faint squeal at lower settings.
Where Human and Canine Hearing Ranges Overlap
Human hearing spans roughly 20 Hz at the low end to about 20 kHz at the high end, though that upper boundary has always been approximate. Research dating back to the 1950s confirmed that sensitivity drops off steeply above 12 kHz, and above that threshold, the ability to distinguish one pitch from another deteriorates sharply as well.2Nature. Upper Limit of Frequency for Human Hearing So even within the technically audible range, your ear is working much harder at 18 kHz than it is at 4 kHz. A sound at 18 kHz needs to be substantially louder before you notice it.
Dogs, by contrast, hear comfortably into frequencies well above 20 kHz. Their ears are most sensitive in a range that overlaps significantly with ours at lower frequencies but extends far beyond us at the top. One recent study measuring hearing thresholds in dogs found that at 20 kHz, the animals could detect sounds at remarkably low levels, around 8.5 decibels sound pressure level on average. That is quieter than a whisper. The researchers suggested that dogs may have evolved this high-frequency sensitivity partly for short-range social communication, since canine vocalizations can include ultrasonic components that humans never notice.3PubMed Central. Determining Hearing Thresholds in Dogs Using the Staircase Method
The practical upshot is that a dog whistle set above roughly 20 kHz sits in a zone where the dog’s hearing is excellent and yours is essentially nonexistent. But set the whistle at 16 or 17 kHz, and you are in a gray zone: audible to you, though not very loud, and very audible to the dog.
Why High-Frequency Hearing Is a Mammalian Specialty
The ability to hear high-pitched sounds is something mammals developed that most other vertebrates never did. Birds, reptiles, and amphibians generally top out well below 12 kHz. The evolutionary reason appears to be sound localization. Small-bodied early mammals needed to pinpoint the direction of sounds in their environment, and shorter wavelengths (which correspond to higher frequencies) are easier for a small head to localize because they interact more distinctly with the two ears.4PubMed Central. High frequency hearing: A uniquely mammalian trait for sound localization
Different mammalian lineages then pushed that upper limit in different directions depending on their ecological needs. Bats famously hear into the hundreds of kilohertz for echolocation. Mice communicate in ultrasonic ranges. Dogs landed in a sweet spot that lets them hear both the low-frequency rumbles of distant threats and the high-frequency rustling of small prey. Humans, relying more heavily on speech than on sound-based hunting, settled into a range optimized for the frequencies that matter most in spoken language, roughly 250 Hz to 8 kHz, with the upper extension to 20 kHz serving more as a peripheral awareness system than a primary communication channel.
Age and the Shrinking Upper Boundary
If you could hear a dog whistle as a teenager but cannot anymore, the explanation is straightforward: the hair cells in your inner ear that respond to high frequencies are the most vulnerable to age-related damage, and they do not regenerate. This process, called presbycusis, starts earlier than most people expect. A study of adults with no known risk factors for hearing loss found that half of participants in the 30-to-39 age group already showed measurable high-frequency hearing loss, and even in the 20-to-29 group, about one in six had it.5PubMed Central. “High frequency presbycusis”-is there an earlier onset?
The decline is gradual but relentless. By your 40s, sounds above 14 or 15 kHz may already be getting harder to detect. By 60, many people struggle with anything above 8 or 10 kHz, which starts to affect the clarity of speech in noisy environments. This is why the “Mosquito” anti-loitering devices that some businesses install to deter teenagers actually work: they emit a tone around 17 kHz that young people find annoying but most adults over 30 cannot hear at all. It is the same principle as a dog whistle, just calibrated for the human age gap instead of the human-canine species gap.
The deterioration is not limited to older adults. Research on children found that hearing sensitivity at 16 kHz was already measurably better in six-to-nine-year-olds than in ten-to-fourteen-year-olds, suggesting that the slide begins before puberty.6PubMed. Extended high frequency audiometry thresholds in healthy school children A larger study of 645 healthy subjects confirmed the pattern across age groups: hearing thresholds climbed steadily as a function of both frequency and age.7PubMed. Extended high-frequency (9-20 kHz) audiometry reference thresholds in 645 healthy subjects So a five-year-old standing next to a dog whistle is likely to hear it more clearly than a twenty-year-old, who hears it more clearly than a forty-year-old, who may hear nothing at all.
What Happens Inside the Ear at High Frequencies
The inner ear is a coiled tube called the cochlea, lined with thousands of hair cells that each respond best to a specific frequency. Low-pitched sounds are processed at the far end of the coil; high-pitched sounds are processed near the entrance, in a region called the basal turn. The hair cells in the basal turn are shorter, stiffer, and more tightly packed, which lets them vibrate at the fast rates that high-frequency sounds demand.
Two types of hair cells work together in this region. Inner hair cells do the actual job of signaling the brain that a sound has arrived. Outer hair cells act as biological amplifiers, feeding energy back into the vibrating membrane to sharpen the ear’s tuning. Research on high-frequency cochlear mechanics has shown that these outer hair cells minimize their steady electrical responses to stay in the most sensitive part of their operating range, while the inner hair cells maximize theirs to reliably signal the brain.8PubMed. Sensory transduction and frequency selectivity in the basal turn of the guinea-pig cochlea Studies of basilar membrane vibration have confirmed that this amplification system is exquisitely level-dependent: at quiet sound levels, the tuning is sharp and selective, but at louder levels the tuning broadens and the response compresses.9PubMed. Basilar membrane vibration in the basal turn of the sensitive gerbil cochlea
This amplification system is also what makes high-frequency hearing so fragile. The outer hair cells in the basal turn are the first to be damaged by noise exposure, aging, and certain medications. Once they stop working, the basilar membrane loses its sharp tuning and the inner hair cells no longer receive a strong enough signal. The sound effectively disappears, not because it is not reaching the ear, but because the biological amplifier that made the ear sensitive enough to detect it has broken down. This is why high-frequency hearing loss is almost always the earliest detectable sign of cochlear damage, regardless of the cause.
Children and Extended High-Frequency Hearing
Young children have the best high-frequency hearing of any age group, and that sensitivity may serve a purpose beyond simply hearing dog whistles. Research on extended high-frequency hearing in children suggests that sensitivity in the range above 8 kHz plays a role in the early stages of language learning, helping young ears pick up the subtle acoustic cues that distinguish similar speech sounds. When this sensitivity is optimal, as it is in early childhood, it appears to support phonetic identification during the critical window of language development.10PubMed Central. Extended high frequency hearing and speech perception implications in adults and children
This also means children are more vulnerable to environmental damage in those same frequencies. Ear infections, certain childhood illnesses, and even moderate noise exposure can prematurely degrade extended high-frequency hearing before a child ever gets a standard hearing test, which typically only measures up to 8 kHz. A child who passes a routine screening could still have lost sensitivity at 14 or 16 kHz, and that loss might subtly affect their ability to hear in noisy classrooms or to discriminate certain speech sounds.
When You Feel a Sound You Cannot Quite Hear
One of the stranger aspects of near-ultrasonic sound is that it can produce physical discomfort even at levels where you are not sure you are hearing anything. Sounds in the 14 to 18 kHz range, sometimes called very high frequency sound, tend to feel disproportionately unpleasant compared to lower-frequency sounds at the same perceived loudness. In controlled listening experiments, participants consistently rated tones at 14, 16, and 18 kHz as more unpleasant than a 1 kHz tone matched for subjective loudness. The subjective loudness of these high-frequency tones also grew more rapidly with increasing sound pressure level, consistent with the ear having a compressed dynamic range at those frequencies.11Journal of the Acoustical Society of America. Sensory unpleasantness of very-high frequency sound and audible ultrasound
This means a dog whistle at the lower end of its range might not sound “loud” in the way you would describe a car horn, but it could still be irritating in a way that is hard to articulate. Some people report a feeling of pressure, a vague headache, or an urge to move away from the source without being able to identify what is bothering them. At higher intensities and frequencies that cross into the true ultrasonic range (above 20 kHz), a cluster of symptoms including fatigue, headache, nausea, dizziness, tinnitus, and a feeling of fullness in the ears has been documented. Researchers coined the term “ultrasound sickness” to describe this constellation of effects.12PubMed Central. Review of Audiovestibular Symptoms Following Exposure to Acoustic and Electromagnetic Energy Outside Conventional Human Hearing Ordinary dog whistles are nowhere near powerful enough to cause these symptoms, but industrial ultrasonic equipment, some pest-repelling devices, and poorly shielded electronic components can.
Bone Conduction and the Ultrasonic Loophole
There is one situation in which humans can perceive sounds far above 20 kHz: when the sound reaches the cochlea through bone rather than air. Bone-conducted ultrasound bypasses the middle ear entirely and vibrates the skull directly, stimulating the basal turn of the cochlea. Research has confirmed that this mechanism allows perception of ultrasonic frequencies that would be completely inaudible through normal air conduction.13PubMed. Human ultrasonic hearing is induced by a direct ultrasonic stimulation of the cochlea
This is not just a laboratory curiosity. Bone-conducted ultrasound has been explored as a communication aid for people with severe hearing loss, since the cochlear hair cells that respond to bone-conducted vibration may still function even when the air-conduction pathway has failed. It also means that if you press a vibrating ultrasonic device against your head, you might perceive something even though holding it in the air a foot away produces no audible sound at all. You would not hear a dog whistle this way under normal circumstances, since you hold a dog whistle at arm’s length, not against your skull. But the phenomenon illustrates that the cochlea’s frequency range is wider than the 20 kHz limit suggests; what limits us is not the inner ear itself but the mechanical filtering that happens on the way in.
Exposure Limits and Safety Around High-Frequency Sound
Because high-frequency and ultrasonic sounds can cause discomfort and potentially harm even when they are not consciously perceived as loud, several standards organizations have set exposure limits. A general recommendation is to keep sound pressure levels below 110 dB for frequencies above 25 kHz, regardless of how long the exposure lasts.14Journal of Occupational Health and Safety – Australia and New Zealand. A review of current airborne ultrasound exposure limits For the general public (as opposed to occupational settings), the recommended limit is more conservative, around 100 dB.15PubMed. Medical and non-medical protection standards for ultrasound and infrasound
A standard dog whistle produces sound levels well below these thresholds, so occasional use around people is not a health concern. The more relevant worry is prolonged exposure to industrial or commercial sources of airborne ultrasound, things like ultrasonic cleaning baths, certain welding equipment, pest-repelling devices that run continuously, and even some LED lighting drivers that emit high-frequency tones as a byproduct. If you have ever walked into a room and immediately felt a subtle headache or ringing in your ears with no obvious cause, a device emitting sound in the 16 to 25 kHz range is a surprisingly common culprit.
Testing Your Own High-Frequency Hearing
You can get a rough sense of your personal upper limit with a tone generator app on your phone, though the results depend heavily on your headphones or speakers. Most consumer earbuds roll off above 16 to 18 kHz, and phone speakers are even worse, so testing much above that range requires better equipment. Start with a 10 kHz tone (which almost everyone can hear clearly), then step up in 1 kHz increments. The frequency where the tone seems to vanish is approximately your current upper limit.
Keep in mind that a quiet room makes a big difference. Background noise can mask high-frequency tones, and the sounds you are listening for at 15 kHz and above are faint even under ideal conditions. Also, the volume at which you run the test matters. You can technically detect a 17 kHz tone at moderate volume even if you “fail” at a lower test volume, because sensitivity at those frequencies is so marginal that a few decibels one way or the other determines whether you hear anything. Clinical audiometry in the extended high-frequency range uses carefully calibrated equipment and controlled soundproofing for this reason.
If you are curious whether a specific dog whistle is producing sound in your audible range, another approach is to simply blow it and adjust the frequency dial. Start at the lowest setting and slide upward. At some point the sound will seem to disappear. That is roughly where your hearing stops and the dog’s continues. The gap between where you lose the sound and where the dog stops responding tells you how much private acoustic real estate the whistle is exploiting.