Feline Communication Behaviour

Key Points

The visual system of cats is predominantly adapted to suit predatory behaviour. Movement detection is greatly enhanced in the cat’s visual system, to the detriment of colour vision and visual acuity. Recognition of the identity of conspecifics is therefore more likely to be based on other sensory information, such as odour. Distance increasing visual and vocal signals between cats tend to be vivid, so that they can be delivered at sufficient distance to avoid fighting.

Introduction

Cats use three main sensory channels for communication; sight, sound and scent. Each of these has certain advantages and disadvantages for communication. Communication in the cat has evolved to enable cats to maintain distance from each other both in time and space, primarily through a system of chemical signals.

Distance Increasing Behaviour

Unlike dogs, cats have not evolved a set of appeasement behaviours that enable them to diffuse tension in situations of conflict. This is because cats are solitary hunters and do not need to manage the sharing of food resources and reproductive opportunities. Fights between cats impair their fitness and ability to hunt, so cats will generally avoid direct confrontation. Cats avoid conflict by maintaining distance from others, primarily using territorial scent marks (urine & claw marks). When cats that are not part of a social group encounter each other, they use vivid body and facial postures and vocalisations to discourage approach.

Distance Reducing Behaviour

Cats are not asocial, they will form colonies where resources are plentiful and they do develop affiliative relationships with each other when there is a mutual benefit. For example, groups of related females may form in an area where there is an excess of hunting and sheltering opportunities. The primary means of identification between cats in a social group is through the establishment of a group odour. This requires that cats approach close enough to groom and rub against each other (allogroom and allorub). It would not be possible to establish a group odour if cats did not have some communicative mechanism for reducing distance. So, distance reducing behaviours are an essential part of communication that allows cats to approach one another.

Allogrooming and Allorubbing

Cats that are part of a social group will groom and rub against each other each other in order to transfer chemical odour signals between cats and establish a "group odour". This group odour is a common identifier that enables members of a social group to recognise each other. A significant benefit of this method of group recognition is that, since the odour is transferred from cat to cat throughout a group, not all cats need to groom each other, or even meet on a regular basis, in order to share enough elements of the group odour to recognise one another when they meet. It should be remembered that this system evolved to regulate interactions between related individuals, and the genetic contribution to personal odour in cats is not yet understood. It may be more difficult for unrelated cats to establish a group odour, if there is less commonality in their personal chemical identity.

Affiliative Behaviour

When approaching to greet another cat, a cat will move its tail into a vertical position (tail-up). A quiet trill or chirrup is issued, and after getting to within around 0.5 metres the approaching cat will sit down. Slow eye blinking is also used to indicate that this is a friendly approach. Physical contact only occurs between cats in about 30% of these approaches. Two cats may approach each other with tail-up, in which case they will often sit down in close proximity, but still without physical contact. When cats do make contact during a greeting, it is often only briefly; one or two rubs or a brief period of grooming. Cats that are younger than 2 years of age are more sociable and also more likely to engage in closer contact after a greeting, possibly even playing.

Visual Communication

Adaptations of the Feline Visual System

The function of the visual system of cats is highly biased in favour of predatory behaviour. The cat’s retina has three times the rod density of the human eye, contributing to the light detection threshold in cats being eight times lower than in man. Although their vision is not monochromatic, cats have sixteen times fewer wavelength comparing retinal ganglia than primates and are behaviourally colour blind. The cat’s enhanced visual sensitivity to brightness, patterns and movement block learning associated with differences in colour; under normal conditions cats do not appear to learn associations based on colour discrimination. The optic nerve in the cat has a much lower density of nerve fibres than in man, due to the much smaller amount of information transmitted from the cat’s retina. This is because the ratio of ganglionic cells to photoreceptors is very high in the cat; there is a far higher level of integration of information at the level of the ganglionic layer of the retina. The benefit of this is that movement detection is hard-wired into the sensory system and able to directly drive fast responding reflexive systems; the cat is therefore much more rapidly attentive and responsive to movement than a human. The overall effect is that cats are attentive to movement in the way that humans are attentive to colour.

The cat's vision has therefore evolved to enable it to see in low light levels, break the camouflage of its prey and quickly detect movement. As a result of the wild cat’s camouflaged coat, crepuscular and nocturnal activity and stealthy use of cover, visual identification of affiliates is less important than the use of other sensory systems such as olfaction.

Signalling

Visual communication involves facial and body postures, as well as the visual aspects of certain behaviour such as spray marking and clawing. In general, visual signals operate over a limited range, in line of sight and are rapidly modified. This enables the signaller to alter its communication according to the response it elicits. Visual signalling is less effective at night, in adverse weather conditions and dense undergrowth. The main disadvantage of visual communication is that it must be delivered face to face with a competitor, which increases the risk of conflict and injury.

Cats use their whole body to convey information about their emotional and intentional state. These signals are vivid, but difficult to modify quickly. The signaller attempts to make itself appear larger and more threatening, or smaller and less threatening. The most powerful signals are those at the extreme, such as the side-on body posture with arched back and tail erect.

Facial postures are less easily observed at a distance, but they can be changed more rapidly and therefore provide a more precise indication of the cat's state at a given moment. Aggressive facial postures are often supported by vocalisations, such as hissing and spitting, that further intensify their meaning. Changes in ear position, pupil dilation and the display of teeth are often not paralleled by body posture changes, since these are slower to accomplish, especially when the animal has adopted a fully erect or flattened body position.

The intention of all postural signalling during a conflict is to maintain distance between individuals, either by intimidating an opponent into a retreat, or by indicating such a low level of threat that an opponent has no attack and the signaller is able to make a discreet retreat. If two opponents engage in physical conflict, one may choose to roll on its back. In dogs, this can be interpreted as a display of vulnerability, and is an appeasement behaviour that diffuses tension and stops further violence. The roll does not carry the same meaning in cats; when in this position a cat is better able to use claws and teeth, and is not attempting to appease or diffuse conflict. After a conflict, there is no need for the kind of post-conflict reconciliation that is seen between dogs. Post conflict reconciliation between dogs reduces the risk of further conflict, and enables individuals to return to their role within the group. Cats that are not part of a social group are competitors and do not have any relationship that needs to be repaired or maintained.

Vocal Communication

Vocal communication includes a wide range of sounds from quiet purrs and trills to loud distress vocalisations. Vocal signals can vary from short to long range, but are always omnidirectional and carry a risk of being detected by cats other than the intended recipient. Vocal communication can be used at a distance in any weather or lighting conditions, and are often used to support and strengthen the meaning of visual signals.

In general sounds that are produced with the mouth closed, such as purrs, trills and chirrups, are distance-reducing signals. The same is true of vocalisations that are produced with the mouth initially open but closing whilst the sound is produced, such as the miaow. Strained intensity vocalisation that are made with the mouth open throughout the sound are generally distance increasing signals or signs of distress. This includes growls, hisses, spits, snarls and shrieks.

There is some evidence that cats are able to modify their vocalisations when communicating with people. In a study investigating human sensitivity to purring in cats, it was found that cats used a "solicitation purr" to obtain a response from people. This purr contains an embedded high pitched component that resembles sounds made by crying human infants, and which people experience as sounding urgent and disturbing.

Olfactory Communication

Scent signals are localised, persistent and offer only an indirect form of communication. They cannot be removed by the signaller once they have been deposited and thus they can convey information about the presence of the signaller that may be to its detriment. For example, giving away information about the resident animal's territorial range and the timing of its activities. Rodents have also been shown to exhibit unconditioned fear and avoidance behaviour in response to feline odours. Toxoplasma gondii infection in rodents has been shown to have a highly specific effect on this aversive response, producing not merely a loss of fear of feline urine odours, but an attraction to them. This enables the parasite to continue its life cycle by infection of its feline definitive host. The behavioural changes seen are completely specific to feline odours, with other fear and conditioning responses remaining unaffected.

Olfactory communication involves the deposition of scent marks in the environment to convey a signal indirectly to another individual. Apart from providing other cats with information about ownership and usage of territory, scent marks also convey information about the identity of the depositor, its sex, health and reproductive status. This enables more complex social organisation than merely avoidance, with cats choosing to avoid an area or attempt to gain control of it, depending on the threat posed by the current resident and the need to gain access to the resources included in that area. Scent signals can also carry a considerable distance, as is the case in urinary scent marks by females during the reproductive season.

The personal identification element of the scent signal has common features with claw marks, spray marks and facial/flank marks, so that the recipient of any of these signals will be aware of which individual is responsible. Previous experience with that individual adds meaning to the location and type of signal.

Marking

Claw, urine and facial/flank scent marks are generally deposited on vertical surfaces, often on objects that are close to an entry point to a particular space, so that other cats will notice them. The function of this marking behaviour is to identify the significance of certain locations to the ‘sender’ and ‘receiver’ of the mark. Scent marks, therefore, act both as a memento of previous experience in a location as well as a signal to others. When a cat encounters facial and flank marks on inanimate objects in the core part of the territory, they signify that this location has been safe in the past and when a cat leaves another face or flank mark, it is relabelling that place as safe based upon its current experience.

The odours that cats share when allogrooming and allorubbing help to identify the group so that these and the core territory chemical messages are a memento of previous interactions.

Other odour marks are intended to enable cats to maintain distance from one another; both claw marks and urine spray marks contain pheromone chemical signals that are intended to signal to cats outside the social group that they are entering an area that is also occupied by other cats.

Facial and Flank Marks

Facial and flank marks are signals largely used in a cat’s core territory, where it only expects to encounter other familiar cats. In areas where facial and flank marks are left, other forms of marking (spraying and clawing) are reduced or absent. From the cat’s perspective, marking of this kind is very efficient. It enables the cat to recognise a safe location from a set of scent mark ‘mementos’ without having to remember details about its appearance and the events that have happened there. This reduces the cognitive burden of processing and memorising the information.

Spray Marking

Spray marks are used to maintain temporal separation by indicating information about ownership of space as well as when a particular cat visits that location. The rate of spray marking by male and female cats is increased during the period when females are in oestrus. As a result, the rate of spray marking in males and females decreases after neutering, as does the pungency of the male spray mark.

Both spray marking and claw marking also include an element of visual display. During spray marking, the cat will sniff the site to be marked, using a Flehmen behaviour to collect more of the pheromone signal. Then it will back up to the site to be sprayed, with its tail raised. During the act of spraying the cat’s tail twitches and moves, the cat has a glazed look in its eye and it will often make treading movements with its hind feet. This pattern is distinct from urination which is usually on horizontal surfaces (unless the cat has urinary tract disease) and is not accompanied by tail movements or treading. The tail movements and treading are part of the process of expulsion of the chemical pheromone signal, but they are also a visual signal that other cats can observe.

The degradation of a urine mark over time provides other cats with an indication of when the depositor was last in that location. Typically, spray marks are used at the outermost boundary of territory and in areas that may be shared with other cats. With regular re-marking, this provides cats with a geographical and temporal map that enables them to pass through an area without encountering one another.

Claw Marks

When scent is released from pedal glands during clawing, this creates a signal that indicates territorial residency. These scent marks are used to indicate a more fixed territorial boundary that is not affected by timing and discourages the entry of non-resident cats into their territory. Clawing behaviour is also used to stretch back muscles after resting, as well as to maintain the condition of claws, so owners are often confused about its meaning as a form of communication.

Pheromones

The meaning of the chemical signal is conveyed using pheromones that form part of the urine-spray, claw or facial/flank mark. Unlike the releaser pheromones that are found in insects, which have a direct and immediate effect on behaviour, mammalian chemical signals have a more subtle effect on mood, emotion and behavioural priorities. For example, in the presence of female sex pheromone a male cat will continue with its current behaviour but its priorities will shift toward seeking out a mate.

In cats, pheromone signals are composed of combinations of fatty acids that are deposited together on a scent marked site. Cat urine also contains the strong smelling compound 3-methyl-3-methylbutan-1-ol (MMB), which is a pheromone precursor. This is produced by the action of the enzyme cauxin, which hydrolyses the chemical felinine that is synthesised in the liver and excreted in urine.

The recipient of the signal will sniff the location, and may perform a Flehmen behaviour in order to draw a larger quantity of pheromone through ducts opening from the roof of the mouth and floor of the nasal cavity into a specialised chemosensory organ called the vomeronasal organ (VNO). The VNO consists of a pair of 1-2cm long tubular organs in the hard palate. Once in the VNO pheromone chemicals bind to a pheromone binding protein before being presented to cell-surface receptors. Signals from the VNO are directed toward primitive brain structures such as the amygdala, that are involved in subconscious changes in mood, emotion and motivation.