Hearing, The Feline Purrspective

Your cat lives in a noisy world. What do cats hear? Cats have some of the best hearing of all the land mammals. They can detect sounds in a range of 50Hz to around 80kHz (Hz measures the frequency or pitch of sounds). In contrast, we humans detect sounds of 20Hz to 20 kHz – the cat clearly can hear much higher pitched sounds than we can (Reference 1).

Usually, larger animals are better able to hear low frequency sound due to larger sound-receiving structures like outer ears and inner ear components. However, unlike other mammals whose middle ear has a single chamber, the cat’s middle ear has two. This increases the range of frequencies over which the eardrum can vibrate, giving the cat one of the widest frequency ranges of hearing. The cat’s hearing is most sensitive between 500 Hz and 32 kHz (Reference 1).

Cats can hear the lower pitched human male voice at 90-155 Hz as well as women’s higher pitched voices at 165 -255 Hz.

your cat lives in a noisy world – what do cats hear

Henry’s Pocket is thought to help with detecting high frequency sounds. It allows the cat to fold his ears flat against his head.

Sound enters your cat’s outer ears or “pinnae”. Most cat have cone-shaped ears that funnel sound into the middle and inner ears, amplifying the sound. Each “pinna” has 32 individual muscles that move and orient it. The pinnae move independently of each other and can rotate 180 degrees (Reference 1).

Distance between the ears allows the cat to pinpoint the location of his prey. Sounds reach one ear before the other, allowing the cat to compare time and intensity of the signal. The cat turns his head to orient toward the prey and his ears then move up and down to further fix on the location (Reference 2).

The nooks and crannies (corrugations) in your cat’s pinnae also are used to obtain information. Incoming sounds reflect off these structures in the ear, intensifying the sound frequencies. The cat is able to gauge the elevation of the sound source and whether it’s coming from in front or behind (Reference 1).

Being able to hear in the ultrasonic range (greater than 20 kHz) helps cats hunt small rodents. Rats, for example, communicate using ultrasonic vocalizations at frequencies exceeding 19–20 kHz (Reference 3). The pinna go into action, helping the cat find his dinner.

Your cat lives in a noisy world – health concerns

Like humans, cats can suffer damage to their ears and hearing loss from illness, toxic drugs and exposure to loud noises. (Reference 4).

Here are some loudness levels of typical appliances in the home. These levels refer to frequencies that people can hear (20 Hz to 20 kHz). An upper limit of 70-80 dB is considered safe for humans. In industrialized society, cats often show a significant amount of changes in the ears thought to be due to street noise, around 70 dB (Reference 4).

Loudness is measured in decibels. Decibels compares a sound with a reference sound, the threshold of human hearing. It is a logarithmic scale: 10-decibel sound is 10 times the intensity of the reference sound; a 20-decibel sound is 100 times the reference intensity, and so on. (https://www.merriam-webster.com/dictionary/decibel)

from: https://www.captel.com/2019/10/noise-levels-household-sounds-infographic/

Appliance	Loudness (dB)
TV	70
Vacuum Cleaner	60-85
Dishwasher	55-70
Food Processor	80-90
Washing Machine	50-75

These noise levels refer to frequencies that people can hear (20 Hz to 20 kHz). What about the intensity of sounds above 20 kHz?

Your cat lives in a noisy world – ultrasonic noise

There is an increasing interest in the loudness of sounds that we humans cannot hear. Current regulations only address human-audible sound. But many human engineered devices produce sound in the ultrasonic range, including cells phones, smart TV’s, and security cameras. Some studies have started to measure ultrasonic noise in our environment. High levels have not been found at this time but as more and more devices come online, it is important to monitor levels of ultrasonic sounds, particularly in our homes (Reference 5).

Our cats hear at these ultrasonic frequencies and their health may be at risk. “Inaudible sounds” (those we can’t hear) have been found to affect endocrine and cardiovascular function, sleep-wake cycles, seizure susceptibility and behavior in laboratory animals (Reference 6). In particular, ultrasonic noise has been linked to Feline Audiogenic Reflex Seizures (Reference 7). Cats develop this syndrome around 15 years of age, it is more likely to occur in cats that are deaf or partially deaf. Protecting our cats’ hearing may put them less at risk of developing this syndrome.

Protecting our Cats from Noise

Be aware that loud, sustained noise of any frequency can damage the structures in cats’ ears. Although there are hoods that cover cats’ ears on the market, it is wiser to set aside a quiet room for your cat in the event there will be sustained loud noises; this room should be free of electronic devices. If you see the cat preferring to spend time in this “noise refuge”, you may want to take some extra steps to reduce electronic noise in your house (Reference 8).

Switch off devices at the plug when practical (and save on phantom power draw).
Locate home media equipment in a closet or garage to isolate ultrasound as well as whine and fan noises you can hear.

Your cat lives in a noisy world. Some of this noise we may not even hear, although our cats do. Be sure to monitor your cat’s behavior. Take steps to protect your cat from potentially damaging levels of sounds.

references

Heffner RS, Heffner HE. Hearing range of the domestic cat. Hear Res. 1985;19(1):85-8. doi: 10.1016/0378-5955(85)90100-5. PMID: 4066516.
Populin LC, Yin TC. Pinna movements of the cat during sound localization. J Neurosci. 1998 Jun 1;18(11):4233-43. doi: 10.1523/JNEUROSCI.18-11-04233.1998. PMID: 9592101; PMCID: PMC6792787
Boulanger-Bertolus J, Mouly AM. Ultrasonic Vocalizations Emission across Development in Rats: Coordination with Respiration and Impact on Brain Neural Dynamics. Brain Sci. 2021 May 11;11(5):616. doi: 10.3390/brainsci11050616. PMID: 34064825; PMCID: PMC8150956.
D.K. Ryugo, PhD1 and M. Menotti-Raymond, PhD. Deafness in Cats. Vet Clin North Am Small Anim Pract. 2012 November ; 42(6): 1179–1207. doi:10.1016/j.cvsm.2012.08.008
Grimshaw-Aagaard, M., Bemman, B. Ultrasonics and urban greening: an exploratory study on ultrasound presence in urban spaces. Pers Ubiquit Comput 28, 677–692 (2024). https://doi.org/10.1007/s00779-024-017]
Turner JG, Parrish JL, Hughes LF, Toth LA, Caspary DM. Hearing in laboratory animals: strain differences and nonauditory effects of noise. Comp Med. 2005 Feb;55(1):12-23. PMID: 15766204; PMCID: PMC3725606
Feline Audiogenic Reflex Seizures. https://icatcare.org/articles/feline-audiogenic-reflex-seizures-fars, published 6/8/24, updated 7/18/24
Cooley, Brian. Your home electronics could be driving your pet nuts. https://www.cnet.com/home/smart-home/is-technology-driving-your-pet-insane/ 11/23/21

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“Music has charms to soothe the savage beast” is actually a misquote of the poem, The Mourning Bride, by William Congreve in 1697. The word “beast” is commonly substituted for the original word “breast”. But perhaps Congreve actually meant “beast” – a similar reference to “savage beasts” and music is found earlier with the Roman poet Lucan, whose work was translated into English by Thomas May in the 1620’s.

“…Whose charming voice and matchless musick mov’d

The savage beasts, the stones, and senseless trees…”

Music can arouse strong emotions in people – it can help instill a martial spirit, make us happy but also make us melancholy and sad. It clearly effects our mood.

Researchers at the University of Wisconsin set out to find music that would affect the moods of our cats. Snowden, Teie and Savage created music for domestic cats that would calm the cats. They observed the responses of cats to the “cat music” and compared these with the cats’ responses to classical music that humans find calming.

Human Emotions and Features of Music

Specific features of music induce particular emotions in humans:

Slow tempos, a narrow frequency range, decreases in pitch, longer sounding of the notes are characteristic of “sad” music
“Joyful” music features fast tempos, increasing pitches and notes tend to be more staccato and not held very long.
“Angry” music is louder and has a higher fundamental frequency; “fearful” music also has a higher fundamental frequency but notes are not held as long.

Snowden and Teie hypothesized that music with the features described above would affect cats in the same way as people, as long as the frequencies and tempos are the same as what is found in natural cat communication.

Cat Music vs Human Music

The “cat music” used in this study had an average pitch that was 2 octaves higher than the human music; it was also 1 octave higher than the fundamental frequency of natural cat communication (“meows” and “howls” were excluded).

The “cat music” also included elements at lower frequencies for the listening pleasure of the cats’ human friends. One piece contained a pulse rate of 1380 bpm, similar to purring, with melodic sliding frequencies; another had a pulse of 250 bpm, similar to kittens suckling, also with melodic sliding frequencies.

Do cats like cat music?

Snowden, Teie, and Savage’s study compared the reactions of 47 spayed and neutered cats to the “cat music” with the cats’ reactions to the human music. Researchers watched for the following responses:

orient/approach behavior

orient head toward speaker playing music
move toward speaker
rub speaker
purring

Avoid/fearful behavior

leaving the room
hair on end
growling
hissing
arched back

results:

Cats showed more Orient/Approach responses to the cat music than the human music. They also approached the source of the cat music more quickly than the human music. There were few Avoidance/Fearful behaviors (9 out of 94 trials – same for both types of music).

Cats were more interested and responsive to music that was designed for them. These pieces were also composed to be calming, so perhaps it is not surprising that there were few “negative” behaviors seen in the cats’ responses to the music. So, when choosing music for your cat, consider the features of the music and what emotional state they may induce. Just randomly picking some classical music to play for your cat may not achieve the goals that you are looking for.

Trying Out Cat Music

In 2019, the cat music was tested in the veterinary clinic at Louisiana State University. Twenty one cats completed the study. The cats presented for 3 examinations, two weeks apart. Each cat was exposed to one of three soundtracks : silence, cat music or classical human music. Each session included an examination and blood draw. The chosen soundtrack was played throughout the session, until the cat was placed back in her carrier.

Cat Stress Scores (CSS) were measured when the cat arrived, during the exam and at the completion of the blood sampling. A Handling Score (HS) was also measured during the examination.

The CSS and HS were not very different comparing cats exposed to silence and classical music; however, CSS and HS were significantly lower for cats exposed to the “cat music”.

cats prefer species specific music

Cat music can help reduce stress-related behaviors. I have found “cat music” useful to calm my kitties

when work is being done on my house
when I am transporting my cats in the car.

The cat music developed for the studies above can be purchased at https://www.musicforcats.com.