While petting cats, I accidentally discovered are fascinated by the smell & taste of earwax, particularly that of humans, and this interest can last indefinitely. Dogs & humans, for comparison, are not. A number of anecdotes have reported this over the years, but no formal research appears to have been done on this. What makes earwax attractive to ? Pheromones? Some nutrient?
Massaging ear mites in a kitten this way); after testing about 7 , I then discovered that are fascinated by the smell and taste of their own earwax. (I’m not entirely sure if they exhibit a Flehmen response, as Kolb 1991 claims. Most of my tests occurred before I learned what a Flehmen response was.) This has held true of most I have tested this on. Searching, I’ve found a number of comments in publications and online also noting this phenomenon. There are not many contexts a owner would notice cats’ interest in earwax, and many of them are actively discouraged (a licking your ear hurts!), but when there is, it appears that earwax interest is often noted. I’ve found that earwax is not even the most interesting earwax: are more interested in dog earwax, and human earwax most of all: the reaction can be quite strong—given the opportunity, a will lick and chew a hearing aid for quite a while, and I’ve had to take away hearing aids from my because the intensity of their licking made me worry about them damaging it. Aside from the cost of replacement, this is a safety concern: hearing aids, earphones, or (especially) disposable foam earplugs are small enough to be eaten & endanger cats’ health.ears while petting them, I accidentally discovered that can enjoy fingers inserted into their ears, perhaps because, like humans, earwax can build up to uncomfortable levels (and I once discovered undiagnosed
I first thought that it might be like sniffing butts, a way to learn about the health/status of another cat1, but that doesn’t explain why dog & human earwax is more interesting, and don’t seem to seek out earwax even after they know about it (except for one of my who’d sometimes try to lick my ears when I was in bed). I find that I sometimes have to touch their noses with a waxy finger before they abruptly become interested (suggesting that whatever the odor is, it doesn’t travel far), and the earwax smell also appears to be fairly temporary as fresh earwax is much more interesting than old earwax, suggesting that the odor also is temporary and volatilizes away quickly (so it’s not a long-lasting chemical inside the earwax which requires eating). Dogs, on the other hand, typically neither appreciate fingers in ears nor show much interest in smelling or licking any kind of earwax.
What is it about earwax that fascinates butyric acid?2 (While there is no shortage of confident assertions that the reason is the “incredibly high concentration of fatty acids and cholesterol” or salt in earwax and similar claims, exactly zero evidence is ever offered for these explanations.)? Is there a particular chemical responsible, like a fat or salt or
Earwax in humans comes in ‘dry’ and ‘wet’ forms, differing by race and I would describe “Identification of volatile organic compounds in human cerumen”, Prokop-Prigge et al 2014 notes that the VOCs do differ quite a bit by race-earwax type (typically less in East Asian)—butyric acid is common to both, but inasmuch as I didn’t see any result from my simple experiments, that may be irrelevant./dog earwax as being like ‘wet’ human earwax; do like ‘dry’ earwax as well?
Prokop-Prigge et al 2014’s Table 1 lists the 46 major VOCs they found along with racial differences; some of them can probably be rejected out of hand as candidates: Limonene (no difference?) would presumably result in having a notable attraction to citrus fruits (they don’t); 2-butoxyethanol or acetic acid or 2-ethylhexanol (no difference?) are used in many cleaning/painting/food products, likewise for the almond-tasting benzaldehyde (difference), and given the lack of interest in human urine/feces, p-Cresol can probably be ignored despite attracting many other animals like mosquitoes or horses or bees. More intriguing is propionic acid (no difference), which WP describes as “body odor”-like and related to cheese (reminding one of & licking sweat), apparently often produced by gut bacteria (ie. smells like “guts of prey”?) and a fatty acid—immediately sounding relevant to feline dietary needs & preferences!—which can be used in animal feed but is not present in high levels in household products that would be exposed to regularly. Other VOCs listed of interest are: caproic acid, MSM, BHT, enanthic acid, & caprylic acid.
Most striking, however, is the entry of “pentanoic acid”, better known as valeric acid (no difference), as in, the second-most famous psychoactive, Valeriana officinalis! This would explain everything: the compound is not terribly common on its own, we know are attracted olfactorily to something in (not necessarily the actinidine which is usually stated to be extract’s active ingredient), are attracted to sweat too which contains isovaleric acid, does not have any known effect on dogs and has minimal effect on humans (it’s used as a herbal remedy but in vastly larger quantities), evaporates quickly, the Flehmen response is precisely how a responds to , response varies greatly between so that predicts earwax interest will vary (of the 2 I have tested with both & earwax, the responder was interested in earwax, and the non-responder was not), while the amount of pentanoic is inadequate to trigger any noticeable psychoactive effect and the response tending to look like ‘passivity’ with the not seeking it out.
This explanation makes several predictions:
- purified valeric acid should be attractive
- dried or aged earwax should be low on valeric acid and low on attractiveness
- the ordering of valeric acid levels in earwax should be < dog < human
- East Asian earwax should be roughly as attractive (as Prokop-Prigge finds similar valeric acid levels as Western ‘wet’ earwax)
- there should be a high correlation between 3 -responding & earwax.
Searching Google Scholar / Google, I’ve found the following anecdotes:
Arny 1990, “A Craving For Wax”: letter to Nature asking if anyone knew anything after noting
I dismissed this as a curiosity until I found that our second Siamesealso liked it. In fact, the second leaps on the bed in the morning hoping to be offered some. I mentioned this odd behaviour to 3 other people and have learned from them that their also liked the wax.
I emailed Arny in November 2019, and he said he “got a few replies from people who had noticed the same behavior with their pet.” but otherwise nothing useful. (I have also told him about the valeric acid coincidence.)
Kolb 1991, “Chapter 25: Animal models for human PFC-related disorders. The Prefrontal Its Structure, Function and Cortex Pathology”, a paper which notes in passing that:
The most common components of the response pattern include approaching, sniffing, and touching the urine source with the nose, flicking the tip of the tongue repeatedly against the anterior palate behind the upper incisors, withdrawing the head from the urine, and opening the mouth in a gape or ‘Flehmen response’, and licking the nose. This behavioural pattern apparently allows olfactory stimuli to reach the secondary olfactory system, which appears to be specialized to analyse odours that are species-relevant.show this response to urine of other , and oddly enough to humans, but they do not show it to urine of rhesus monkeys, dogs, rats, or hamsters. They also do not show it to fecal matter or fur, although they do show it to earwax!
At one time we had 13and 7 dogs. I began being very interested in communications with and dogs and the subtle body languages that animals use to communicate. We had a named Que tu bu who loved to lick the earwax out of our ears, which was a strange scratchy affair, though clearly a showing affection and love toward a human. Later, as a teenager I became interested in Marine Biology…
Rinaldo also mentioned this in a 2016 essay:
After minutes of stroking, Catabu would suddenly pop up on his back paws and place his front paws on my shoulder. He would then begin to probe my inner ear with his scratchy tongue. His whiskers tickled as he dug further, licking my ear slowly and deliberately. This was somehow a pleasurable experience, though his tongue was sticky.behaviorists, would speculate he was claiming me as litter-mate. I think we were exchanging love and affection. This was my first trans-species experience. Here was a , finding pleasure in the taste of my earwax while we provided mutual affection. This /human relationship eft a lasting legacy and deep-probing questions for me about animal-human communication, symbiosis and the contemporary notion of the computer interface.
Lynch 2007, “‘No Writer Nor Scholar Need Be Dull’: Recollections Of Paul J. Korshin”, in a memoir of English professor Paul Korshin, recollects:
At the Osage house, Paul revealed himself as a dotinglover. He and Debra had adopted brother and sister tabbies he’d named Oscar and Sherwin for his undergraduate mentor at City College. Oscar, the color of an orange creamsicle, would jump into Paul’s lap and purr during the seminars. Paul would cradle him, saying, “He likes to be made much of.” Both had free run of his exquisite suits, though he kept lint tape handy to pick up the fur. When Paul met my tuxedo Edgar, I mentioned that Edgar was partial to earwax. Intrigued, Paul said, “I don’t know if I have any”, but he put a finger to his ear and allowed Edgar to lick off the spoils. In time, Gaylord and Holly would join Paul and Debra’s family. We exchanged Christmas cards over the years “from our house to yours.”
On the general Internet, someowners have noted this behavior:
Stuart Moffat, in a 2003 rant explains it on the usual chemical/taste theory, but also drops some curious comments:
…if something smells good but tastes like shit then we won’t eat it, but if a plasticine if they’re covered in gravy. Try it—it’s non-toxic and you can pepper your turds with interesting multicoloured lumps…Disclaimer: The author does not endorse the feeding of plasticine to on a regular basis. Only when they’ve shit on your bed, coughed up a furball on your brand new novation nova II, or scratched the fuck out of your 200 quid carhartt coat. In fact fuck it, now I think about it, feed the little cunts whatever you want.likes the smell of it, it has to taste fucking awful before it won’t eat it. A will eat small lumps of
Oscar has an ear wax fetish. Will locate and chew any used cotton buds, ear plugs etc. My OH has also been wakened on a number of occasions by Oscar sticking his tongue in his ear! :eek:
or sandy-: , 2018
Oh I forgot—Sandy is also obsessed with my earplugs. I won’t let him near them as I’m worried he would accidentally swallow one—but it doesn’t stop him having a good old sniff (even when in my ears!).
or crocky, 2012:
She’s fond of earwax, so when she notices that we clean out our ears, she tries to grab the little stick out of the trash again. then she’s off to a quiet and peaceful spot and starts licking it… :eek:
or dee o gee, 2010:
You can’t stick anything remotely resembling a cotton bud or earphone in your ears around Bunty, or she will literally try and assault your ears and hands to get to it and lick the earwax off it. :eek:
The 2005 thread where 9 owners mention observing thisSite forums:
2012 blog, “Why Some ; 6 Like Earwax” owners mention observing this
Quora has many entries for this (either the questioner or an answer):
- “Why is my kitten so obsessed with my ears? He nibbles on them and sticks his nose as far as he can in them.”
- “Why do like the smell of earwax? My often tries to take my son’s earbuds and earplugs.”
- “Why do like the taste of earwax?”
- “My knows where I keep all my spongy green earplugs, and fishes them out when I’m not looking, and consumes them like Cheetos. Is there something about human earwax that is like a delicacy to ?”
- “Why do like the smell of earwax? My often tries to take my son’s earbuds and earplugs.”
- “My wife snores and I wear polyurethane foam earplugs at night. My likes to eat ones that he finds on the floor. He even looks on the floor. They go right through his digestive tract unaffected. How bad is this fetish for earwax for him?”
- “For what reasons is my kitten licking me so much?”
- “Why does my lick the inside of my ear?”
- “Why do like ear wax?”
online hearing aid retailer Audicus posted a 2018 blog post, “Cats and Earwax: An Internet Theory Explored”, after noting “We got curious after seeing multiple tweets about coming after hearing aids.”, and noting a number of YouTube videos demonstrating it
Dogs: while I’ve found little interest by dogs in earwax per se, other dog owners have noted dogs licking ears of humans or dogs and ascribe it partially to earwax: eg “My Dog Licks My Ears—Why?”, “Ask a Vet: Why is My Dog Licking Ears?”
The Humane Society of the United States Complete Guide to ↩︎Care, Christensen et al 2004, notes in its ear cleaning section that with multiple who are good friends, it might be unnecessary, because it is a “allogrooming (mutual grooming) task that seem to love doing for one another.” Because of social bonding or to learn about each other—or because earwax is interesting & another is the easiest source? (I’ve never owned which were good enough friends, apparently, to see this for myself.)
Both butyric acid and salt would also explain the interest in licking sweaty hands/armpits. I tested out the possibility of butyrate on my earwax-loving A 2006 chemistry forum discussion outlined a number of strategies for obtaining butyric acid, of which the second simplest was adding lye and the simplest was rancid butter. I made rancid butter by putting a few tablespoons of butter into a ziplock bag inside a tupperware and storing it on top of my hot water heater for a week and a half; after a day it had melted and separated into a yellow liquid & a solid white mass, and after a week it smelled bad. I stored it in my refrigerator, and tested my 3 times by offering 2 saucers of a tablespoon of rancid butter and butter which I heated simultaneously in my microwave for 10s. All 3 times, if he started with the rancid butter, he would eventually lick and eat a little of the rancid butter, but slowly and without enthusiasm, and switch to the fresh butter which he would eat more of and much more enthusiastically, and vice versa, always leaving more of the rancid than fresh. The earwax-style fascination was absent for both kinds of butter. It’s possible that the rancid butter had other breakdown products which offset the appeal of the butyric acid, but I would have expected different behavior if he was simultaneously attracted & repelled. I further tested ‘caramelized butter’ (butter heated up to a point where it browns, which can be sweetened and used as delicious cake frosting); my liked it, but another I tried was almost indifferent. For a followup experiment, I bought some lye and mixed 2tsp lye with a quarter stick of melted butter (vs another quarter, both left to cool to room temperature), which turned it darker yellow and gave it an odd smell (albeit not nearly as strong as the ‘rotten’ butter smelt) eventually hardened to a cracked white crust, and tried it on my ; again, he showed no interest in the treated butter compared to the normal ‘fresh’ butter.↩︎.