CAT CHAT! CAN CATS TALK?
Can cats talk? Many cat owners would like to think so and some even claim that their cats speak a number of recognisable words. A Brazilian cat takes claims one step further by apparently being able to sing a number of well known songs while the Fortean Times carried a report of a cat which speaks several words in Turkish and suggested, with tongue firmly in cheek, that the reason many owners cannot understand their cats is because the cats are speaking Turkish. But before cat-owners rush out for phrase books, are these cats really speaking or are their owners just talking turkey?
In 2008 a Chinese grandmother, Granny Lv, of Changchun city, claimed her male cat Mimi could speak Chinese. His vocabulary included 'laolao' (Grandma) apparently copied from her granddaughter. His other phrases are 'ren ne?' (where is everyone) on waking up and finding no-one around and 'gan sha ne?' (what are you doing?) when Granny Lv plays mahjong. Her neighbour, Mrs Wang claims Mimi's pronunciation is very clear, but girlish. Unfortunately, the 2 women are hearing what they want to hear when interpreting feline sounds. So perhaps cats are talking Cantonese or Mandarin instead?
Katharine Simms in "They Walked Beside Me" (1954) wrote: "Several people have, however, claimed that their animal could speak with human speech. Frederick Eddy, former president of the Siamese Cat Society of America, has said that his Siamese queen [female cat] Adamina used to greet him every morning with a cordial and distinct 'hello!' "
For humans, the terms 'speech' and 'talk' are not restricted to vocalization, but encompass human body language (which most of us read without realising it), gestural languages (sign language) and tactile languages (of deaf-blind individuals) which are equally expressive among those fluent in their use. Further, human language comprises both verbal and non-verbal components (including the written extension of body language through gestural substitutes such as the <VBG >, :-) symbols within Internet communication).
The cat's vocal apparatus differs from our own and is not designed with speech in mind. However cats need to communicate, both with other cats and with owners. They "speak" to each other through body language, communicating feelings and intentions through posture and facial expression. Scent is also an important component of cat communication. In addition, they have a vocabulary of sounds ranging from caterwauls to mewing sounds, from hisses to the "silent meow" which is probably a sound pitched too high for human ears to hear. The familiar "miaow" is used mainly for communicating with humans as we are evidently too thick to understand anything other than kitten-talk.
The remainder of this article will be concerned with vocalizations - the vocalizations used in cat/cat communication and the vocalizations used in cat/human communication. For more detailed information on feline body language and non-vocal feline communication, refer to Cat Communication. You may also wish to read Do Cats Have Emotions?
DO CATS HAVE LANGUAGE?
In "Alice Through the Looking Glass", Lewis Carroll wrote "It is a very inconvenient habit of kittens that whatever you say to them, they always purr. If they would only purr for 'yes' and mew for 'no', or any rule of that sort, so that one could keep up a conversation! But how can one deal with a person if they always say the same thing?"
On the other hand, "Your Guide to Cats & Kittens" (1973) produced by Pedigree Petfoods/Peter Way Ltd wrote that "mew" did not do justice to the cat's wide vocabulary - ranging from greeting to plaintive - and went on to compare the different vocalisations of several popular breeds: Siamese, Burmese, Longhair (Persian) and British Shorthair.
Lewis Carroll, it seems, was not a keen observer of cats, otherwise he would have noticed that cats do not always say the same thing! They make a variety of different sounds which, among humans would be called "words", but in our belief that we are naturally superior to "dumb" animals, we don't call cat-sounds "words". Since the sounds don't conform to our notion of grammatical structure, it simply appears that cats lack language.
To the uninitiated, and probably to Lewis Carroll, the simple "miaow" is an all-purpose word. Most cat-owners, however, are aware that there are a whole variety of miaows that differ in pitch, rhythm, volume, tone and pronunciation. Jean Craighead George attempted to categorise these according to the cat's age, gender and situation:-
There is more to felinese than the simple miaow though. In 1944, Mildred Moelk made a detailed study of cat vocabulary and found sixteen meaningful sounds, which included consonants and vowels. She divided cat-sounds into three groups:-
Although these may not be used in grammatical sentences, one definition of language is "any means, vocal or other, of expressing or communicating feeling or thought" (Webster's Dictionary). Observant owners will notice the following sounds which cats make to communicate their state of mind (this list is not exhaustive, since cats will improvise):
Note: While cats may lack the complex and abstract emotions of humans, they have basic emotions characterised by responses in certain regions of the brain. These basic emotions, which include fear, distress and anger, are discussed in Do Cats Have Emotions?. This is not anthropomorphism - cats' brains have similarities to our own brains and are often studied in laboratory experiments (please note, Messybeast.com is opposed to invasive or otherwise distressing experimentation).
The exact meanings of all of these sounds may be modified or emphasised by facial expression, tone/volume, body language and context (paralanguage). In his dealings with Scottish Wildcats, Mike Tomkies noted that the wildcats would greet him with a loud spitting "PAAAH" accompanied by a foot-stamp. I have received the same greeting from feral cats. The meaning ("*** off!") is unmistakable and only a fool (or a cat-worker intent on packing pussy off for neutering) ignores it. Some cats may use some of these cat-sounds in different ways when communicating with humans and only our familiarity with our own pets tells us that a certain type of growl is a play noise and not warning of imminent attack.
Another suggestion for teeth chattering, in outdoor cats at least, is to hypnotise prey. Some owners have claimed that cats can call birds, even flying birds, closer by chattering at them. Personally, I consider it unlikely that cats are imitating birds to encourage them to approach and the chattering more likely related to the birds being out of easy ambush range. I also find it unlikely that the chattering hypnotizes prey such as squirrels or chipmunks though it might make the animals curious enough to overcome caution. Many prey species don't have good colour vision and rely on movement for their visual clues and are lulled into a false sense of security. By sitting still, the cat is almost invisible, but it is becoming tense with excitement. Teeth-chattering may be related to the build-up of tension in a cat's body before it pounces or rushes its prey - you can see the cat tensing its limbs. The chattering seems to be an overspill of excitement. Another sign of emotional leakage in a stalking cat is the twitching tail.
Cat-owners will recognise many of the cat-sounds listed, although we may refer to them in more anthropomorphic terms: greet, grumble, nag, whimper, swear, sing etc. Some cats add their own idiosyncratic words to this general vocabulary such as the sudden exhalation of air used by my own cat, Aphrodite. This word, which we call "foof" or "frooff" can be anything from an exclamation ("Oh!" and "Well"), a comment ("So?" and "Huh?"), a non-committal response when we speak to her ("Hmmm"), or a noise to be used when she feels she needs to say something, but can't think of anything meaningful to say (small-talk and self-satisfied murmuring). It all depends on HOW it is said. For Aphrodite, "froof" is the all-purpose "supercalifragilistic..." of cat vocabulary. Scrapper used "mrrrp" in the same way.
Other idiosyncratic sounds reported include what David Kennedy calls a "Squabble - a series of short and long meows and grunts made in a complaining tone that occur when a cat is moved or made to do something it would rather not do". "Roaring" is more often associated with big cats than small cats, but nevertheless there have been several reports of domestic cats that roar, often to proclaim "I am here". Roaring in pet cats should always be investigated by a vet as it can be a symptom of throat problems. Some caterwauling tomcats suffer partial voice loss after strenuous yowling and end up roaring. Maybe those few perfectly healthy cats that roar their territorial claims were lions in a past life.
Brian Vesey-Fitzgerald "Cats" (1958) wrote that the cat's language was insufficiently studied compared to birdsong. "All those who have studied the language of cat and dog are agreed that the dog has a rather limited vocabulary and uses only consonants, but that the cat also uses vowels and has a large vocabulary." He mentioned the blind musician and cat-lover Marvin P Clark, who wrote the book "Pussy and her Language" in 1895. Clark's book was often dismissed because it contained much nonsense (perhaps because Clark could not visually observe the cats), but his keen musical ear and his blindness made him very sensitive to the sounds cats made. Vesey-Fitzgerald noted "that no one who has studied cat language since Clark's day has distinguished so many, or anything like so many, is no sound reason for saying that they do not exist" suggesting to his readers that more recent researchers were not as perceptive of sound as a blind musican!
François Chateaubriand, a French author and politician, who died in 1848, made a serious study of the feline vocabulary and detected the consonants f, g, h, m, n, and v. Clark detected b, d, f, l, m, p, r, t, v, w, and y. Carl van Vechten heard m, p, r, s, t, and said that he never heard v and that m was less common than p, r, s and t. Ida M. Mellen heard ch, f, h, k, l, m, n, p, r, s, t, w, and y. While this might be due to the sensitivity of hearing (with Clark, a blind musician, having the most sensitive), modern linguists note that our brains become programmed early on to hear the sounds of our native language and that unfamiliar sounds heard in adult life are pigeonholed as a "best fit" according to what we have learnt to hear as a child.
More fanciful and less scientific attempts at categorising cat sounds have produced dictionaries of words. According to Katharine Simms in "They Walked Beside Me" (1954): "In 1895 Alphonse Leon Grimaldi, FRS, published a paper in New York on the discovery of a cat language. The cat's voice is modulated as is man's [...] in the cat's voice the French author, Champfleury, counted sixty-three different notes, though Darwin spoke of only six or seven. But the Abbé Galliani counted twenty inflection, and vowed that the cat's language is a 'tongue' for 'they always employed the same sound to express the same thing'. Marvin Clark, the blind author, has published a cat vocabulary of seventeen words which he says repeatedly occur in the talks which cats 'struggle to carry on with members of their household'. Some of these words such as bl for meat, aelio for food, and ptleebl for mouse, may seem far-fetched, but I feel that mi-ouw for beware, burrieu to express contentment, parriere for open , and mi-youw for 'I'm here', are reasonable and recognisable. Mr Clark adds that as well as the seventeen main words the cat uses about 600 root words capable of inflection and many combinations, which are by tone of voice, graded with subtle shades of meaning. Now a Washington doctor has agreed with Marvin Clark and also compiled a cat-language dictionary. Even in the sixteenth century Montaigne wrote 'doubtless cats can talk and reason with one another. It has been pointed out that dogs use only vowel sounds, but cats include at least six consonants in their speech."
LEARNING THE LINGO
Pedigree Petfood's book "Your Guide to Cats & Kittens" observed that a cat’s vocabulary increased as it matured. Initially, newborn kittens only purred (contentment) or mewed (distress). They learned to interpret the wider range of noises made by their mother, and in response they developed the ability to make a wider variety of communicative sounds. In fact this process continues throughout a cat's life - owners who frequently talk to their cats are often rewarded by cats who "talk" back to them.
Kittens learn a great deal from imitating their mother, and cats retain the ability to learn and adapt into their adult life. They soon discover that humans use sounds in order to communicate and most cats react to this by developing different sounds for certain circumstances. A plaintive miaow is best suited to achieving a goal such as extra grub or an open door while a friendly chirrup elicits a favourable response when the cat greets its owner. Many of these noises are accompanied by exaggerated actions as the cat "acts out" its communication - by running back and forth between owner and closed door or by licking invisible crumbs from an obviously empty food dish.
Humans have an innate language instinct and a need to communicate vocally (or through sign language etc) with everyone about them. Adults with small children use a simplified version of language known as baby-talk (called "motherese" by some linguists) where certain words and syllables are greatly stressed and frequently repeated. These efforts are rewarded when baby makes noises back and parents readily identify meaningful noises ("mum-mum") in their babies when the rest of us hear only random babble. In response, parents talk even more to their offspring.
Whether or not we consider our cats to be surrogate children, we tend to relate to them in a similar way, using motherese to communicate with them. Cats may respond to this verbal barrage by making noises of their own. After all, if their humans need to communicate through all this audible chit-chat, any self-respecting cat is going to have make noises if it is to stand any chance of getting attention! And since the owner lacks much of the necessary apparatus needed for speaking felinese (tail, mobile ears, whiskers, erectile fur) it is up to the cat to learn humanese.
One feature common to both cats and people is the use of a slightly raised tone of voice to indicate friendliness and a lowered tone of voice to indicate displeasure, aggression etc. Friendly chirrup and food-seeking miaow are usually uttered in a raised tone of voice while the low-pitched growl of a cross cat is undeniably unfriendly. Volume is sometimes used for added emphasis e.g. a strident miaow for urgency, a gentle "brrp" for contentment. Cats which simply feel compelled to add their two penn'orth to a conversation often do so in a neutral tone of voice to indicate that they are not being particularly hostile, nor unduly friendly, nor is there any great urgency about the subject matter.
ARE SOME BREEDS MORE TALKATIVE THAN OTHERS?
Most owners of Siamese and Oriental cats say that these breeds are more talkative than other breeds. Beneath their non-Siamese colouring Orientals are basically Siamese cats, with the modern Siamese being chattier than the older style Siamese.
"Your Guide to Cats & Kittens" (1973), produced by Pedigree Petfoods/Peter Way Ltd compared the different vocalisations of several popular breeds: Siamese, Burmese, Longhair (Persian) and British Shorthair.
Siamese cats were well known for talkativeness, but were often simply dismissed as noisy, yowling cats. Siamese vocabulary included "A longish mew of medium pitch is often emitted soon after the cat is let into a room. This is possibly purely conversational, serving to inform people that it has arrived and is passing the time of day. A far more plaintive sound is made whet cats wish to be let in or out, or to attract attention to themselves if they feel they have been unjustly ignored. Very occasionally, Siamese may be heard ‘speaking’ in the middle of a yawn which would appear to signify that they wish others to be made aware of their boredom or fatigue. There is also a lowish stuttering sound, used to make complaints of a rather general nature. This is by no means an exhaustive list of Siamese ‘phrases’ but rather a random selection."
"Burmese are likewise given to oral communication but, as a result of having a slightly narrower range of pitch than the Siamese, they rely on variations in length and volume of their mews to provide a large number of different ‘remarks’. In contrast, British Shorthairs tend to show the reserve traditionally attributed to their human counterparts; they vocalise a lot less than the Orientals and their mews, when uttered, are usually brief. A range of pitches can none the less be detected. Sharp sounds generally signify distress or impatience, while those of medium pitch are used for less urgent situations such as polite request for food. A mew emitted whilst purring usually means the animal is contented. Long-haired breeds, on the whole, have rather high-pitched voices, and unless they are extremely upset the volume of their mews is fairly low. To see a small, fluffy kitten quietly requesting attention almost makes a human being - who is in no place to translate his feelings to the cat - think the kitten realises that the appeal of its face makes noisiness unnecessary."
These general findings are repeated again and again - Siamese cats and their relatives are highly talkative while longhaired cats, not only the Persian Longhairs, tend to be quiet. I have not found the native cats of Thailand and Malaysia (the Thai/Malay equivalent of moggies) to be particularly talkative, so possibly it is something which was bred into the modern western Siamese breed at the same time that its colour and conformation were being refined.
CAN CATS TALK PEOPLE-TALK?
"Language", by definition, is not merely a collection of words strung together. It is a collection of words strung together in a particular and meaningful way so that the words have meaning in relation to each other and can frame an overall concept. Language is more than just words. Language has grammar (basic rules) and syntax (sentence structure).There are many excellent books about language; my personal recommendation is "The Language Instinct" by Stephen Pinker - it is both informative and clearly written.
Humans have an instinctive need to communicate with fellow humans and to receive communication in return. This drive is often extended to our interaction with non-humans. Just as we look for recognisable sounds when babies learn to talk, we look for recognisable sounds in our cats' "vocabulary". Rather than simply distinguishing a "feed me" miaow from a "let me out please" miaow we try to interpret some of these sounds as words and are remarkably good at self-deception, so if the "I want more grub" noise sounds a bit like "keow" we think our cat is calling us a cow for not giving it a big enough helping in the first place. Cats which "talk" are probably making native feline sounds that sound a little like human words and which, if delivered under the right circumstances, are interpreted as words by beings geared to verbal communication.
I say probably, because here there is a slightly grey area. According to American vet Dr Michael W Fox cats can learn behaviours through observation. My own observations suggest that some cats learn to imitate certain sounds as well. Cats can make sounds and work out which sounds elicit suitable responses from humans (positive feedback). Can cats therefore learn to make certain sounds i.e. imitate certain human sounds if they know it will get a favourable response? Here I will have to give cats the benefit of the doubt. It may be that, in spite of lacking the apparatus for speech, some cats do indeed make the effort. Equally, it may be that owners are over-compensating for the cat's inability to talk and are hearing what they want to hear, regardless of what the cat has really said!
Another feature of human speech is that it comes in bursts; a mix of different sounds and pauses between sounds, plus inflection and intonation. Tone of voice probably means much more to a cat than the actual words used, although many owners maintain that their cat understands every word they say. Cats certainly manage intonation and can miaow in a questioning manner, a demanding manner, a forlorn manner or simply as a statement. By observing our response they adopt the various tones of miaow for appropriate circumstances. Puss probably isn't thinking "I want to go out so I shall ask nicely," he is more likely to be thinking "I want to go out and I know that this type of noise usually does the trick."
In their attempts to communicate with us on our own level, some cats put together full "sentences" of noises and pauses. They might simply be inviting us to talk back to them (most cats like this sort of attention from their owners). It is interesting that such cats string together a series of different sounds into a single burst of communication, with pauses between "words", which an owner likens to a sentence. Scrapper (one of felinity's brighter sparks) could hold his own in a conversation with me although I haven't a clue what he was saying, he just liked to talk and liked me to talk back. If he did understand what I was saying to him he could have taken the Business Studies exam with me (if he was trying to enlighten me on a particular aspect of management structure then I'm afraid it went right over my head). Some owners say that their cats do much the same and are right chatterboxes, with Siamese and Oriental cats being particularly vocal.
Norman Barron's girlfiriend's cat Coco is also a conversationalist. Norman has identified 23 distinct phonemes in multiple combinations that significantly diverge from the familiar "meow". These include sounds like a coyote howl, one like "meeeyr-laackh" (she shakes her head after using a clicking phoneme) and various mumbled words and phrases, some of which sound similar to English - including one that resembles "iloveyou"! Coco also makes a cute surprised/interested sounding "oooh". Like Scrapper, Coco enjoys holding conversations with her humans, responding to their speech with patterns of sounds that mimic the sounds and cadence of human speech.
I doubt very much that cats, those from C S Lewis's Narnia excepted, can truly speak, although cat-sounds are more diverse and more meaningful than Lewis Caroll suggests. What I don't doubt is that there are a number of cats having a jolly good attempt - whether in Turkish, Cantonese, Mandarin or any other tongue. What is worrying though, is when I am doing the evening shift at a cat shelter and I am convinced that I can hear someone talking, even though there are no other humans, only cats, in the vicinity. So far none of the cats have owned up!
HAVE CATS EVOLVED TO COMMUNICATE WITH HUMANS?
While not claiming that cats have acquired the power of human speech, in 2002, a Cornell University researcher investigated whether cats vocally manipulate their humans. Nicholas Nicastro, a graduate student working under psychology professor Michael Owren at Cornell University's Psychology of Voice and Sound Laboratory said that cats were obviously very dependent on people for their needs and that they may have evolved to become better at managing and manipulating people. While domestic cats may not know language, his study suggested that cats, which have lived alongside humans for thousands of years, have adapted their "meows" to better communicate with humans.
One way Nicastro attempted to prove his theory was by analysing a range of domestic cat vocalisations, playing these back to humans and then screening people's reactions to each type of sound. He did the same using the calls of wild cats in order to compare domestic cat and wild cat "speech". He recorded more than 100 different meows from 12 domestic cats (2 of them his own), soliciting various sounds from the cats by placing them in different situations (with their owners' help since cats rarely co-operate with strangers). These situations included delaying feeding time, before feeding them, putting them in empty rooms with the recorder, brushing them beyond the animals' patience for brushing and simply recording the contented meows of cats in a good mood.
Nicastro played the recordings to two sets of people. The first group of 26 people was asked to rate each meow in terms of how pleasant each sounded. The second group of 28 people rated the sounds in terms of urgency. He compared people's ratings with acoustical analysis of the meows and found a clear pattern.
"Pleasant" meows were shorter in duration, with higher frequencies and tended to descend in pitch (change from high to low notes). "Urgent" meows were longer in duration, with lower frequencies and ascended in pitch (began on low notes and escalated to higher ones). Rarely was a meow classed as both "pleasant" and "urgent" at once. The highly urgent calls tended to be the least pleasant-sounding while the highly pleasant ones were rated less urgent.
Nicastro suggests that cats may therefore have developed different kinds of calls to "hook into human perception tendencies" and alert us of their mood and needs. He points out the animals have certainly had time to adjust for people since their domestication in Egypt over 5,000 years ago [Note: cats were domesticated simultaneously or earlier in Pakistan]. With their shorter life spans than people, cats have had many more generations to evolve ways of manipulating their owners through their calls. This theory is flawed because in order to pass on the meow-manipulation skills, those cats more adept at manipulating humans would breed and those less adept would fail to breed. The proliferation of feral cats around the world shows that cats can co-exist with humans very well without manipulating people through their "speech".
Does the ability to communicate with humans provide a clear survival advantage so that good communicators/manipulators survive longer and produce more offspring than poor communicators? Probably not since it is only relatively recently that cats have become house-pets rather than utilitarian animals (rodent controllers). Other researchers admit that it is possible that cats may have co-evolved with humans to better communicate with people, they caution it's easy to jump to conclusions. Douglas Nelson, a professor of bio-acoustics at Ohio State University reminds us that cats have evolved different calls to communicate with each other. The communications with humans are modifications of the noises they use among each other.
As well as recording pet cats, Nicastro went to a zoo in Pretoria, South Africa to record the calls of the wild desert cats from which modern domestic cats evolved. These are still being analysed and have not been tested on humans, but his preliminary findings reveal very different vocalisations. The wild cats have cries which are harsher and less musical-sounding than domestic cats or, as other people have commented, "like cats on steroids".
Strangely, it does not appear to have occurred to Nicastro to record the cries of feral cats - cats which are domestic cats in all but their habits. If feral cats have the same range of meows as their fully domestic counterparts then cat language probably evolved for inter-cat situations and is merely modified for the cat-human situation. My own experience with rescue cats leads me to conclude that Nicastro would do well to analyse inter-cat communication (particularly that between mother and kitten) for its pleasantness and urgency - and compare their use of body language in cat/cat and cat/human situations - before jumping to any co-evolutionary conclusions!
DO CATS HAVE DIALECTS?
In 2009 (personal correspondence), Al Bradley suggested that cats living in feral colonies or household groups developed distinct vocal dialects laernt as a kitten and which possibly not be easily understood by cats outside of the grouping. This would be similar to the regional dialects learned by songbirds. Unlike songbirds, which vocally advertise for mates and declare territorial ownership, cats primarily communicate through body language and scent marking so vocal dialects are unlikely to develop. They use vocal communications as kittens and retain this when "talking" to humans. The vocalisations between cats are relatively limited and usually accompany body language. Many cats develop distinct sounds for talking to humans; sounds they have learnt will get them the desired response and that may sometimes mimic the sounds made back to them by the owner (pitch changes and cadence).
Al had contact with 2 litters of kittens from the same mother cat. Though raised apart, the kittens in both litters developed the same style of vocalisation that he believes were learnt from the mother. Further cats kept with the first litter apparently also started making the same vocalisations. He wondered if this meant cat social groups developed their own dialects and whether cats from outside the group had difficulty in communicating. Personally I believe the vocalisations have been adopted because it gets the desired response from a human and other household cats are copying it for that reason. Once out of kittenhood, cats have little use for the meows and chirrups that are so familiar to humans.
If there are differences in "dialect" between isolated groups of cats, Al wondered if this would account for why many cats have difficulty making "friends" with cats from outside their group or that an older cat's inability to accept a new cat may be based on the inability to learn the new cat's dialect. Conversely, cats that roam freely in a neighborhood from a young age may have mastered all the local dialects and may therefore get along with most neighboring cats. This is unlikely. The antipathy towards incomers is related to territoriality rather than linguisitic issues. Cats meeting each other communicate with eyes, ears, whiskers and posture rather than vocally. A free-roaming cat may have earned rights of way through a number of territories or its scent may be familiar enough that it is not challenged. When a cat is introduced into a household, it is an intruder into the resident cats' territory. There may be growling and hissing, but the communication is otherwise non-vocal. I've observed many introductions and cat-cat encounters and found little vocalisation, but a great deal of body language to communicate mood and intent.
While it is possible cats living in groups may pick up particular greeting sounds, apart from mother/kitten greetings, those greetings are mainly used with humans and not with other cats. A cordial cat-cat greeting involves flank-rubbing, nose-bumping and tail-sniffing rather than mews or chirrups. I don't believe vocal communication is important enough among cats for there to be distinct dialects that help or hinder communication between unfamiliar cats.
THE ENIGMATIC PURR
Although not strictly a vocalisation, the purr is an important means of communication and, depending on the cat's situation, it can convey contentment, pleasure or be placatory behaviour (i.e. "I am not a threat to you"). As well as purring when happy, cats also purr when severely injured, frightened or giving birth. A cat may even purr when close to death. The Pedigree Petfoods book discussed the familiar purr and noted that cats being restrained for veterinary procedures (blood samples or X-rays) frequently purred. The inference drawn from this behaviour was that the cats were indicating that they were tractable and co-operative and would not need to be forcibly handled.
The purr was therefore likened to the obsequious behaviour of a submissive cat when avoiding conflict with a larger, more powerful animal. It also noted that some cats, both male and female, gave low growl-like purrs as a warning when a stranger entered their territory. This is inaccurate, the "growl-purr" is in fact a low growl.
Purring is caused by vibration of structures in the throat, though previous explanations have attributed the sound to the noise of blood turbulence in the chest! A truly ecstatic cat sometimes vocalises (uses its vocal cords) while purring, resulting in a shrill noise. Purring is also found in the cheetah, puma and most small cats such as the serval and ocelot. Big cats such as lions, tigers, jaguars and leopards cannot purr because their throats are built for roaring. Conversely, the small cats, puma and cheetah, screech or yowl rather than roar. Although there are a few reports of purring-type sounds (a breathy groaning sound rather than an in-and-out purr) from lions and tigers, it seems that a cat can either purr or roar, but not both!
Since purring uses energy and has been passed on through many generations of cats, it must have some function. One puzzle was why a sick or injured would expend energy on purring, when it needs all its energy for healing? Researchers believed that suggestions that the cat's purr evolved solely to communicate self-contentment goes against evolutionary theory. The fact that cats purr when injured suggested that it had some survival value, for example a healing function. Cats close to death may also purr, suggesting a pain relieving function. Since many cats purr when on their own, the purr cannot merely be a form of communication - why would a cat purr when there is no-one around to communicate with?
Though this sounds far fetched, research in humans has shown certain frequencies of vibration relieved suffering in over three-quarters of test subjects suffering from acute or chronic pain. Ultrasound is often used alongside physiotherapy. Effects include (depending on the patient) generating new tissue growth, augmenting wound tissue strength, improving local circulation and oxygenation, reducing swelling and even inhibiting bacterial growth. Vibration at low frequencies and low intensities can aid bone growth/repair, tendon and muscle strength/repair, joint mobility, reduce inflammation and reduce breathlessness. I have had ultrasound treatment on damaged tissue in a broken foot and one curious effect was a hot feeling at the fracture site!
The soothing effect of a purring cat is well-known to cat lovers. Researchers believed that vibrating (purring) cats were communicating more than just a sense of well-being to their owners. Fauna Communications and ENDVECO initiated a research project recording and analysing the purr to see if it was linked to healing.
Cats are reputed to have nine lives. Their bones tend to heal rapidly and relatively easily. I came across the case of Didi at the Chelmsford CP shelter - Didi's back legs had been so badly broken he should not have been able to walk. He had been found as a stray with his fractures already healed, albeit not entirely straight, showing the amazing self-healing capacity of cats. There are cases of feral cats surviving accidental limb amputations without human intervention. The ability of a large percentage of cats to survive a fall (High Rise Syndrome) is legendary. It is little surprise that a veterinary saying goes "If you put a cat and a sack of broken bones in the same room, the bones will heal." Compared to dogs, cats have fewer orthopaedic problems or muscle injuries and though attributed mainly to their flexible skeleton, self-healing might also play a part. Researchers wondered if the purr provided therapeutic vibrations to speed this healing.
To investigate this theory, scientists recorded and measured the purring of relaxed cats. To measure purr frequency and how purr vibrations spread throughout the cat's body, an ENDEVCO Model 22 accelerometers was used. These are little bigger than a match head and could be fixed to the cats' skin using washable glue and medical tape. About 6-10 minutes of purring were recorded. The cats' purr frequencies were within the therapeutic range of 20 Hz (hertz) to 200 Hz (actual frequencies were 25 Hz, 50 Hz, 100 Hz, 125 Hz, 150 Hz). The most therapeutic frequency ranges are 25-50 Hz and 100-200 Hz which speed bone repair.
Though to humans, the purr is most often considered a sign of contentment or of a cat reassuring itself, the researchers concluded that after a strenuous activity (hunting, defending territory etc), a period of purring could act like a massage session and alleviate sprains and strains as well as speeding the healing of any wounds. The sense of relaxation many owners feel when cuddling a purring cat suggests that the therapeutic function of the purr can extend to humans.
ADAPTING THE PURR TO COMMUNICATE WITH HUMANSIn 2009, researchers at the University of Sussex wrote in the journal "Current Biology" that cats use a "soliciting purr" to manipulate their owners. Unlike regular purring, the "soliciting purr" incorporates a "cry" with a similar frequency to a human baby's. Cats produce a low frequency purr by activating the muscles of their vocal folds, causing them to vibrate. Vocalisation is due to the vocal cords held across the air-stream snapping shut at a particular frequency. Purring and vocalising use different mechanisms so it's possible for the cat to embed a high-pitched cry into an otherwise relaxing purr. The more energy that goes into the cry, the more urgent and unpleasant the purr becomes. The cry normally occurs at a low level in normal purring, but cats learn to exaggerate it when it proves effective in getting a response from humans.
Other studies found similarities between a domestic cat's cry and the cry of a human baby - a sound that humans are highly sensitive to. Some people have even mistaken the overheard cry of the Siamese cat (a particularly vocal breed) for that of a baby.
Lead researcher Dr Karen McComb said the research was inspired by the insistent early morning purr of her cat Pepo. Research discovered that the pestering purr was more likely to get owners out of bed to feed the cat while simply meowing got the cat shut out of the bedroom. "Soliciting purrs" sound more urgent and less pleasant than ordinary "non-soliciting" purrs. The relative level of an embedded high-frequency sound could increase the annoyingness of the purr and hence the likelihood of the owner responding. The "soliciting purr" is more common in cats that are highly attached to a single person.
My thanks go to Prof Mark Woodroffe, lecturer at Anglia Polytechnic University, Essex, for stimulating my interest in linguistics. I don't think he believed me when I told him that cats could talk! Although this web article is now a long way removed from my linguistics assignment, it was Mark who challenged me to write the original version.