Cats communicate in a variety of different ways, and to properly understand cats it is vital to appreciate how and why they communicate.
In the preliminary stages of aggressive or combative behaviours, cats will tend to avoid looking at each other directly. Indeed looking directly at a cat may be interpreted as challenging/aggressive by the cat, which may be one reason cats often seem to choose people to sit on that are relatively disinterested in them!
Visual signals are important for communicating mood and intentions. Body postures, expressions, pupil size, and their ability to erect hairs on some or all of the body, are all involved in visual signalling. However, compared to wolves and dogs, cats have relatively immobile and flat faces which somewhat limits facial expressions.
The tail position is one of the well characterised means of visual communication – generally the ‘tail up’ position with the tail held vertically in the air, perpendicular to the ground is signalling friendly intent when the cat approaches another cat, animal or human – ears are normally pricked up and whiskers are relaxed. Other tail positions and movements will communicate other moods or intentions – a tail held out, slowly moving from side to side across the body may indicate aggression, and in more extreme cases the tail may be held up and ‘puffed out’ by raising the hairs (piloerection) to make the tail and cat appear bigger – this is usually continued as a strip along the spine as well. The tail being tucked between the back legs often signals nervousness and/or submission.
Visual signals are not limited to tail position – facial expressions are very important too, in particular alterations in position or movement of the eyes, ears, and mouth; and whole body posture is also significant. Erect ears and holding them rotated out along with narrow/ small pupils usually signals anger and aggression, whereas pupil dilation and ears being held down against the head usually signals fear. A relaxed cat will usually have its ears facing forward in the normal position.
An arched back may indicate the cat is in a defensive mode, and a cat crouching down ‘cringing’, often with the tail thumping on the ground is classic defensive posture. A stretched body may indicate either confidence or, in some cases, aggression with a readiness to attack.
Eye contact can also be important – staring, with little blinking is a challenge, while relaxed eye contact with blinking and winking, sometimes with half-closed eyes is non-threatening and indicates contentment. Also when tense or highly alert the whiskers will be fanned out and point forward in front of the face, whereas when the cat is relaxed the whiskers point directly out and are less spread. A frightened/nervous cat may flatten the whiskers against the side of the face and bunch them together.
A variety of other visual communication signals are recognised in cats, but not all are well understood. It has been postulated that scratching behaviour (scratching repeatedly on a vertical surface for example) may in part be a visual signal, perhaps involved in some way in territorial marking. However, scratching areas tend to be within the routes most commonly used inside a cats ‘home territory’ and do not appear to be used to mark out the periphery. Many cats will also roll at times – rolling on their backs and exposing their abdomen. Again, this is not well understood, but it has been suggested that this may be a friendly/submissive posture.
Common forms of tactile (touch) communication include allorubbing (two cats rubbing their bodies against each other - this especially occurs around the mouth/cheek area, but also along the body and tail regions), allogrooming (two cats grooming each other) , nose touching, and resting/curling up together. Cats using each other as ‘pillows’ is a behaviour that is seen both in domestic and feral cats, as is cats backing up against each other and intertwining their tails. This is assumed to be a form of social bonding, but as with much of signalling behaviour between cats, the full subtleties of what is being communicated is difficult to appreciate.
Some studies have suggested that allogrooming behaviour (which most often concentrates on the head and neck area), is quite often associated with agonistic behaviour and thus allogrooming may be a way of redirecting potential aggression in situations where attempts are being made to avoid overt aggression. However, allogrooming largely occurs among cats that are related and/or have strong familiarity thus probably enhancing social bonds.
Tactile communication in part overlaps with olfactory communication (see below) as there is transfer and exchange of scent marking during a number of tactile communications.
Cats display a wide range of vocal communications, and they have been classified in different ways. Cats are said to have one of the widest ‘vocabularies’ (i.e. different patterns of vocalisation) of all carnivore species, and this may be related to the fact that in the natural environment vocal communication is important when they spend much active time in poor lighting conditions. Vocal communications are generally used for either 1) agonistic interactions, 2) sexual interactions, 3) mother-kitten interactions, and 4) cat- human interactions.
In general, three basic forms of vocal communication are recognised:
‘Murmuring’ sounds. These are mostly formed with the mouth closed, and are generally sounds used for greeting, attention, acknowledgement and approval. This includes purring which is used in a wide variety of contexts and also has a wide variation in its different forms. Kittens may purr when they are being nursed as a sign of contentment and the queen may also purr, probably to reassure the kittens – it is thought that this may be the origin of purring behaviour. Later in life purring is generally used as a greeting and care- soliciting call and is often used, for example, during allogrooming. It has also been thought that purring may signal that the cat is not a threat to others. Domestic cats purr at a frequency of 25-150 vibrations per second, and all members of the Felidae family have the ability to purr. However, unlike members of the Felis group (the smaller cats) who can purr constantly, cats in the genus Panthera (cats that roar such as lions, tigers, leopards and jaguars) can only purr while they breathe out. The ‘trill’ or ‘chirrup’ sound, which is used as a friendly greeting call, also falls into this category of murmuring sounds.
‘Miaowing’ or ‘vowel’ sounds. The cat has a very extensive range of miaowing sounds, and these are used to communicate a variety of messages. Generally the miaow is used to communicate friendly interactions with other cats, but they can carry a variety of specific messages (e.g. high pitched miaowing of hungry kittens, short high miaows in adults that suggest displeasure etc.).
‘Aggressive’ sounds. These are all made with the mouth held open and are characterised as growls, yowls, snarls, hisses, spits, shrieks, and wails. These are all sounds made in association with various forms of aggression whether offensive or defensive, and can be aimed at other cats or other animals.
Olfactory (smell or scent) communication
Cats have an extremely well developed sense of smell and this is used extensively for communication. Chemical signalling can be very specific, can last for a long time and can spread over considerable distances. Signalling through smell is vital to enable a cat to identify its territory, identify other ‘friendly’ individuals when cats are living in a colony, to indicate sexual receptiveness, etc. It is likely that many complex and (for us) poorly understood messages can be communicated through scent and smell in cats. It is possible that in colonies of cats, smell is not only used to communicate between cats in the colony, but the exchange of scents may lead to the development of colony- or group- specific odours for communicating with other groups.
Urine and faeces. There are two obvious sources of scent that are used by cats. It has been observed that while cats will typically bury their faeces when they defecate well within their territory, when they defecate on the edge or boundary of their territory they are more likely to leave it uncovered, thus helping to demarcate the extent of their territory to others, and perhaps also to themselves. How important faeces is in signalling between cats remains speculative, but many carnivores do use faeces, along with glandular secretions from the anal glands, to convey information to others. Urination and urine ‘spraying’ (i.e. depositing urine on vertical surfaces at various sites) may also be a way of marking territory, giving messages to other cats in a colony or nearby, and may carry other signals too (such as sexual receptiveness in the unneutered female). Urine spraying is observed more commonly among males than females. Feline urine contains two unusual amino acids - felinine and isovalthene - and the degradation of these amino acids appears to be responsible for at least a part of the odour associated with tom-cat urine. Entire male cats may excrete up to 95 mg of felinine a day, whereas females produce only about one fifth of this amount. The fact that cats seem intensely interested in the smell of urine of ‘foreign’ cats is proof of the importance of urine in signalling between them.
Skin. The skin of the cat produces scent too, particularly through sebaceous (oily) glands and the chemicals or pheromones that they produce, just as in urine. Certain areas of the skin are particularly rich in these glands such as beneath the chin, the sides of the mouth and cheeks, the sides of the forehead, the tail base and along the tail. Cats rubbing against each other helps to exchange scent and presumably encourage affiliative behaviour. Similarly cats will often rub against objects in their ‘home’ area depositing their scent. The practice of cats rubbing their heads against objects (depositing their scent) is known as ‘bunting’. It is not certain whether all areas of the skin produce similar secretions/odours, but which area of the head is used to rub against objects appears to simply depend on the physical location (height) of the object suggesting there is unlikely to be a difference between different facial secretions at least.
This bunting activity seems to occur especially in the ‘core’ area of their territory and appears to be associated with comfort, reassurance and friendly social interactions. Cats appear to be able to locate rub-marks very easily, suggesting that they have a strong odour for cats, although these are not detectable by humans. Female rub marks appear to convey information about their sexual cycle and receptivity to males.
Feet. Sebaceous glands are also present on the feet and between the toes, thus scratching behaviour (on trees, posts etc.) may be associated with leaving a scent mark as well as a visual mark of the cat’s presence. Cats tend to scratch in the same places repeatedly, and these tend to be along the well-used routes in the cats territory rather than at the periphery. While helping to condition the claws, it is likely that this does leave a clear visual indicator of the cats presence and this is probably reinforced by the odour associated with the sites.
Given that cats have changed little from their wild ancestors, and the relatively small numbers of generations involved in domestication, it is likely that the repertoire of signalling in domestic cats is very similar to that in Felis sylvestris lybica. However, because of the increased social living and communication between domestic cats it is possible that they have adapted to use these signals in different ways.