The UK cat population in 2012 was estimated to be around 8 million (source PFMA) with approximately 19% of all UK households owning at least one cat.
The trend of cat ownership shows increasing numbers generally and the proportion of those in multi-cat households is rising. While it is clear to see the benefits of this for us, as carers, is this necessarily a good thing for the cats?
The cat’s social life
Felidae (the biological family of cats) are solitary predators that, with the exception of lions, do not live in socially structured groups. However, while the wildcat ancestors of domestic cats are solitary animals, the social behaviour of domestic cats is more variable depending primarily on the density of cats in the area and availability of food sources. Felis catus (the species that is the domestic cat) has proved to be a remarkably adaptable species, and while retaining its roots as a solitary hunter, in a number of situations (both natural and artificial) will adapt to group living through the development of social structures.
For a species that is essentially a solitary hunter, it is important for cats to establish a territory (ie, hunting territory) and that this is defined in such a way as to generally avoid conflict with other cats (for the survival of the species). Cats therefore mark their territories using scent derived from facial glands, urine, faeces, and anal glands. This territorial marking, together with the extremely sensitive sense of smell in cats, helps them to communicate effectively and to minimise direct conflict. In the wild, territories may overlap with ‘neutral areas’ where cats may greet and interact with each other. If a strange cat encroaches into another cat’s territory, this will normally provoke an aggressive interaction to chase off the cat, firstly through staring, hissing and growling and, if that is ineffective, through a short, noisy violent attack.
Feral cats can and will form small colonies based around available food sources. This does not inevitably happen, as some will live singly, but it is not uncommon for small groups of co-operating females and kittens to develop. Relationships are complex, with stronger affiliative relationships between some cats and less affiliation with others – this may in part be influenced by how related they are, age, sex etc. However, they develop neither a social survival strategy nor a pack mentality and they continue to be solitary hunters. Thus cats are not ‘pack’ animals but have the ability to adapt to form social groups. Where social groups of cats do exist, they appear only to work well when the members of the group are familiar and when there is no competition over food or other resources.
As cats have developed largely as solitary hunters without the need for complex social interactions, they appear to have a relatively limited ability for complex visual signaling that occurs in many other animals that do exist in social groups. Thus they are less able to signal appeasement to other cats which means that in situations of conflict there is a much higher probability of fighting.
The social life of the companion cat
Groups of companion cats form differently to those that occur naturally in the species. Humans select those cats that live together, they may or may not be related. They are routinely neutered (an appropriate measure for the companion cat) and they are then either confined within a property with no opportunity to put distance between them or allowed to roam in a wider territory that may contain numerous other unrelated cats, some in close proximity. This potentially puts the companion cat under a great deal of pressure but as an adaptable species it is fair to say that some cats choose social contact with their own species, many will avoid it (given the choice), all cats are capable of living alone, and most will adapt to a solitary existence.
What happens when it goes wrong?
If there is tension between members of a household group or the resources available within the territory is perceived as limited or scarce, cats will either learn to avoid each other, using communication geared towards increasing distance between each other, or adapt to the situation by suppressing natural behaviour to avoid conflict. In cases where the individual is unable to adapt it may develop chronic stress leading to behaviour that represents a problem for the owner, such as urine spraying or inappropriate urination, or stress-related disease such as idiopathic cystitis. Some cats may indulge in those normal behaviours that are deemed safe, such as grooming, sleeping and eating, but to an excessive level as a means to self-sooth in stressful circumstances. If a cat has access to the outdoors, and is a confident individual, then it may choose to ‘leave home’ and establish territory where it perceives the resources to be more plentiful and constantly available to fulfil its needs.
The key to success
Multi-cat households can work well under the right circumstances. There are three important factors that influence success:
1. Compatibility of the cats within the group
2. Availability and accessibility of resources
3. Population density of the cats in the territory
Siblings that have been brought up together often represent the best pairings, particularly if there was evidence of sociability with each other as kittens and their temperaments remain complementary, for example, probably not one very confident kitten with one very shy one.
If the multi-cat household is established with a number of cats within it then it is possible that they do not form one single cohesive group. Once cats mature they can form sub-groups – pairs, factions of three or more and singletons. These individual groups then cohabit within the territory making every effort to avoid other groups and remain at a distance.
If these social groupings can be identified then, in theory, an optimum environment can be provided that distributes cat resources within the home to take into consideration the need of each individual group not to share with another.
Identifying social groups
This can be achieved by observation: which cats spend time together, grooming each other, sleeping in close proximity or touching, playing together and greeting each other nose to nose? Conversely, which cats show active aggression towards each other, which cats leave the room when another enters and which cat stares at others? The easiest way to do this is to write the names of the cats in the household and show colour-coded arrows from one cat’s name to the other in the direction that accurately describes the behaviour observed, eg, cat A grooms cat B therefore an arrow indicating social, friendly behaviour points from A towards B on the diagram. Once all the interaction observed has been shown on the diagram then it should be possible to establish which cats group together and which work alone.
Two-dimensional plans of the property layout are useful at this stage to show how each cat or group of cats use the ‘territory’ within it. This can be achieved by observing the cats over a period of time and establishing which rooms they frequent regularly and which they avoid. If the cat resources are located in a minimum number of locations then each group will have to cross over common areas to get to the essential provisions and these ‘potential areas of conflict’ can also be noted.
Availability/accessibility of resources
Cats don’t share important resources with other social groups. These resources include everything a cat may need to survive and thrive, ie, food bowls, water bowls, litter trays, beds, high resting places, private areas, scratching posts, entry/exit points and toys.
If these resources are provided in sufficient numbers and distributed so that the locations chosen are accessible for each cat or social group’s core area (where they spend most of their time) then tension and conflict can often be avoided. Various suggestions have been made regarding appropriate numbers but a commonly used resource formula is: one resource per cat, plus one extra, positioned in different locations. For example, in a four cat household the owner would be recommended to provide five of everything.
Cats are solitary hunters and feeders yet they will suppress behaviour in order to obtain vital nutrition and adapt their eating patterns to avoid hostility, eg, eating large amounts at a time or making frequent visits to avoid eating with others. Therefore a strategy to minimise conflict may be:
- Measured amounts of dry food left throughout the day so that cats can choose when to eat
- Measured more frequent mealtimes if wet food is given
- Bowls positioned to allow the cat to face any direction when eating to observe any approaching adversary
Cats prefer to drink away from feeding areas and may avoid drinking altogether if challenged by another cat. Therefore a strategy to minimise conflict may be:
- Locate water bowls in different areas away from food.
- Provide large ceramic, glass or stainless steel bowls, filled to the brim so that the cat can remain vigilant while drinking.
- Position the bowl to allow the cat to face any direction when drinking to scan for any adversary.
Cats will eliminate when and where they feel safe, away from feeding and hunting areas. Some cats prefer to eliminate outside but many, given the choice, would use indoor facilities. To exhibit silent, passive aggression cats may block or guard access to litter trays to prevent others using this limited and essential resource. If cats do not feel safe eliminating then it can lead to stress-related problems such as urinary retention, constipation, bladder or bowel disease or inappropriate urination or defecation in quiet corners, for example. Therefore a strategy to avoid conflict may be:
- Position litter trays away from full length windows, cat flaps, noisy appliances, external doors, thoroughfares and busy areas.
- Covered trays may make a cat feel vulnerable or trapped.
- Open trays allow the cat to have a full view of its surroundings.
- If in doubt, provide choice of facilities and litter substrate and keep a record of their use.
- The litter substrate that seems to appeal to the majority of cats are the fine, sand-like clumping products that are easily cleaned.
High resting places
High perches are used as part of avoidance strategy and cats will gravitate towards high places when threatened. They can then observe without risk of attack. Therefore a strategy to avoid conflict may be:
- Providing high perches throughout the house, for example:
- Tall modular scratching centres
- Two access points to each perch, if appropriate, to avoid the risk of being trapped by another cat
- These are places where a cat observes without drawing attention to itself so owners are best advised to not acknowledge the cat when it’s there
Cats need ‘time out’ from each other and from humans too. This is usually a dark, warm place that they perceive as safe. Therefore a strategy to avoid conflict may be:
- Provide soft bedding, for example:
- Under beds
- Remove a divan drawer, if appropriate
- Inside wardrobes
- Cardboard boxes
- Cat carriers or covered beds
- Do not disturb or interfere
- Minimal cleaning disruption
Cats need somewhere safe to rest, free from danger and interference, preferably off the ground, warm and free from draughts. The master bed is ideal as it has a strong scent of the owner and the security that this person represents. Cats may block or ‘defend’ beds or ‘steal’ them from other cats to demonstrate their ability to control resources. Cats also use sleep or feigned sleep as a coping strategy at times of conflict so safe beds are important. Therefore a strategy to avoid conflict may be:
- Consider access to master bedroom; is this an area of conflict?
- Provide soft, warm, raised beds
- Provide beds with a source of heat, eg, heated pads to encourage use in separate locations
- Scent of owner (clothing, towels) if preferred
Scratching posts provide a visual and olfactory mark, as a means of territorial communication. They are also necessary for claw maintenance and exercise. Excessive scratching in a particularly significant conflict zone can be found and may also be used as an alternative marking strategy to urine spraying. Therefore a strategy to avoid conflict may be:
- Provide vertical and horizontal surfaces
- Tall enough posts or panels for full stretch
- Vertical striations on the scratching surface
- Rigid structures so they resist the scratching and don’t move
- Emphasis on locations near thoroughfares, beds, entrances to core areas
Cats may guard, block or intimidate other cats at an entry and exit point as this may be the only possible access to the only available latrine site. Therefore a strategy to avoid conflict may be:
- Provide 2 entry/exit points on different aspects of the house:
- Access from upper floor to flat roof
- Front/back doors, side entrances
- Provide indoor litter facilities in some cases
Play is considered a leisure activity by cats and insecure individuals will not play in front of a more confident cat. It is however an important and positive behaviour but in multi-cat households play, particularly play fighting, can escalate into something more antagonistic. Therefore a strategy to avoid conflict may be:
- Follow the resource formula (if toys provided for object play)
- Play separately without another cat present
- Inter-cat play:
- Provide high perches to avoid play fighting from escalating
- Provide objects for cats to play around
Owners are important too!
Cats will withdraw from owners if other cats are more assertive and contact can be location and time specific. To avoid conflict, allow the cats to dictate quality and quantity of interaction and avoid the desire to be equitable by ‘sharing’ affection.
Population density in the area
Cat population densities vary between 1-2000 per km², with densities above 50 cats per km² only found in urban areas. Domestic pet cat population densities exceed those that occur naturally, particularly as each cat household contains separate social group/s. The external population of cats has an impact with a high population density creating high stress factor, irrespective in many cases whether or not the resident cats have an indoor or outdoor lifestyle, as cats can be observed through windows and odours come through draughts in doors and windows. Therefore a strategy to avoid conflict may be:
- Avoid multi-cat households (or limit to 2 cats) in areas of high population density
- Consider a secure garden to exclude other cats
- Use safe deterrents in the garden if cats are coming into the garden and bothering indoor cats
In conclusion, multi-cat households are not all bad but the choice of individuals involved matters and they need careful management and resource provision to ensure that each cat has what it needs. Following these simple guidelines will help towards reducing stress and making a multi-cat household a positive experience for owners and cats alike.