Key Points

  • Cats are a discretionary social species; social groups are formed under certain circumstances, but this is not essential to the survival of the individual.
  • The functional basis for the formation of social groups is kitten rearing by groups of related females.
  • Groups form when resources are abundant, and break up when they dwindle.

Introduction

Cats have often been mistakenly characterised as solitary animals as a result of their depiction in popular literature, and this false perception has persisted in the popular imagination. Whilst they do use distance-maintaining behaviour to avoid direct conflict with each other, the importance of social interaction in this species is clear from the presence of specific distance decreasing and affiliative behaviours.

Natural social groups are made of related female cats, kittens and juveniles. If resources are insufficient to comfortably maintain a group, surplus females will leave or be displaced from the group as they reach maturity and become direct competition for resources with established group members. As they approach reproductive maturity, males leave the group and secure their own, much larger, territories, visiting different groups of females to mate.

Group Size

Tolerance of group size varies considerably within Felis silvestris, with some subspecies such as the Scottish wildcat (Felis silvestris grampia) being almost completely solitary, and others such as the African/Near Eastern wildcat (Felis silvestris lybica) being more sociable and group living. This may reflect climate differences in the locations where these subspecies evolved; in temperate and cold climates where human population density is also low, sources of food and shelter may be more sparse and subject to greater competition. Genetic studies indicate that the domestic cat is descended from Felis sylvestris lybica[1], which would suggest a higher level of sociability in the domestic cat compared with UK-native wild cats.

Observational studies by authors such as Leyhausen[2], Laundre (1977)[3] and Fagen (1978)[4] expanded knowledge of the social communication and organisation of cats, and revealed their capacity for group living. The work of authors such as Dards (1978[5], 1981[6], 1983[7]), who studied dockyard cats in the UK, and Denny et al. (2002)[8] have identified a now well recognised functional template for domestic cat organisation in which related female cats form social groups along with their offspring and juvenile cats. The purpose of the groups is to aid in successful kitten rearing. Males are loosely associated with these groups of females and roam a much larger territory that encompasses the home ranges of several groups of females.

Groups of females form in areas where food and shelter resources are abundant, but group members still continue to act independently of one another. Unlike some species in which females are hostile to the offspring of conspecifics, nursing queens seem to show little discrimination when caregiving to kittens; they will feed and groom any kitten that approaches them[9]. This adaptation provides the basis for the formation of female social groups, as it enables kittens to be protected and cared for by members of the group whilst others are hunting. Even so, the only sharing of food between cats is between mothers and their kittens; meals are not shared between adult females.

Until they are completely weaned and able to catch and kill their own prey, kittens are not a source of competition for resources with adult cats, because their nutritional requirements are met by the mother. Once young cats become fully independent, they do become potential competitors for food and shelter resources. If these are not sufficiently abundant then females may leave the group.

Whilst there are situations in which resources naturally occur in high density, human settlements appear to be a significant driving force behind the formation of more permanent feline groups[10]. Where people are absent, and locations of high resource density are therefore absent, cats favour a solitary lifestyle other than when they are raising kittens[11].

Social Behaviour

Aggression is seen between adult females that are not members of the same social group, as there is competition between groups for access to food and shelter. The maintenance of territorial boundaries limits contact between members of different groups. However, juvenile cats are more receptive to social contact with unfamiliar individuals, which may favour the formation of new groups by young adult cats.

When cats rub against each other and groom each other they transfer scent to create a common group odour. In wild or feral cat groups, individuals may already share strong odour similarities since in most cases groups are composed of related females. Allorubbing and allogrooming of this kind are essential to social bonding but do not contribute to self-maintenance; cats can groom themselves successfully without assistance from others.

Male cats generally do not tolerate contact with each other, and will compete strongly for control over access to an area that encompasses the home ranges of groups, or individual, female cats. However, some authors report that well-matched males sharing a neighbourhood will occasionally stop fighting and form loose social relationships that are termed “brotherhoods”[2].

Neutering alters the social behaviour of male cats, reducing their territory size and the level of inter-male conflict. This is observed in large suburban cat colonies in which neutered males participate equally with females.

Social structure in a domestic setting

In a domestic context, groups are formed by the successive introduction of unrelated individuals by the owner. There is no function for the group, and there may be a mix of breeds, age, sex and personality traits (such as sociability). New cats may be introduced when the resident cats are in middle age; a time when their sociability may be reduced. This creates an artificial social setting in which individuals that would, in a wild or feral context, be unlikely to form a social group, are brought together. In a domestic setting, conflict and tension become increasingly likely as group size increases, or resources need to be shared. Lacking a functional social structure that incorporates all individuals, with domestic cat groups characteristic individual group and individual behaviour can become apparent:

Cliques or Factions: groups or 3 or more cats that show greeting and other affiliative behaviour towards each other, but may be aggressive to other members of the domestic group.

Pairs: Pairs of cats, often littermates, that greet and show affiliative behaviour towards each other.

Social facilitators: These cats will often offer and receive greetings and affiliative behaviour with cats from several factions or cliques. They may also associate with other cats outside the group and serve to maintain group odour between individuals and sub-groups that rarely interact directly with each other.

Satellite individuals: These offer and receive little or no greeting or affiliative behaviour with the other cats in the home. They may be involved in minor or passive aggressive incidents with other cats in the group, often as the recipient of threat.

Despots: These individuals may deliberately monopolise resources and create opportunities to intimidate other cats in, and outside the home.

Multi-Cat Households

Like their wild ancestors, domestic cats have the capacity to form social groups, but they do not need to do so. There is no evidence that singly housed cats experience stress related health or behavioural problems. However, stress related behaviour problems such as indoor spray marking[12] are more likely in multi-cat households. Greater levels of conflict are observed in multi-cat households, which is identified as an underlying factor in stress related health problems such as feline idiopathic cystitis [13]

Given the increased probability of inter-cat tension in multi cat households, and the very high cat population density in some urban areas, owners should be encouraged to exercise caution when considering the introduction of additional cats to a household. Although some cats do form strong social bonds with each other, these relationships are not the norm and are not something that cat owners should expect to see. Single housed cats with a suitably enriched environment has no intrinsic need for the companionship of another cat; the default state of cast is as solitary hunters that do not need to associate with other cats in order to survive. This means that cats can live alone perfectly happily. Provided that they have a sufficient supply of safe territory, food, shelter, and opportunities to play and exercise, then they will cope very well. The cat is free to mix with cats outside and, if it is a sociable individual, it can find friends there. If, however, the cat is not particularly sociable then it can avoid other cats and live a happy life alone. Some cats definitely prefer to have their own home, without other cats in it, so it is important to think carefully before getting another cat.

If you intend to keep several cats indoors, without outside access, this can also cause problems. You will need to adapt the house to provide the cats with space and a whole host of resources and activities to save them from becoming bored or stressed by the absence of privacy from other cats.

In the wild, cats do often live in groups, but these mainly consist of related adult females and immature cats. They are extremely intolerant of outsiders and unwilling to live with a cat they are not related to. So if the desire is for two cats to live together, it is best to get them as littermates. If this is not possible, very young kittens can be raised as if they were from the same litter, provided that this starts at a very early age i.e. before they are seven weeks old.

If an adult cat or older kitten is to become an additional cat in a multi-cat household, then the new cat must be introduced very carefully. Apart from introducing the new cat correctly, it is important to make sure that the resident cats have plenty of the resources they need so that they feel comfortable to coexist without competition.

Suitable Multi-Cat Household Cats

Research has shown that resident adult cats are more likely to accept the introduction of a new cat if it is much younger than them. They are far more intolerant of same-aged or older new cats. Research also suggests that resident cats are more likely to tolerate a new cat of the opposite rather than the same sex and that, in cases of same sex pairs, two males are slightly more likely to be compatible than two females. Some older cats do feel intimidated by kittens, as they may feel unable to stand up to physical play. So, getting two young kittens reduces the pressure on the older cat because the kittens can play together.

Replacing a Housemate

Friendships between cats are unique and individual and they cannot be replaced by bringing in a new cat. If a pair of littermates has been raised together, their bond is particularly strong and irreplaceable. The remaining cat may experience genuine grief and may search for and call out to the missing one. This kind of grieving can go on for several months and is certainly not a good time to bring in another cat. Any new cat may be met with intense hostility. Even if the new cat is introduced well after grieving has ended, the bond is unlikely ever to be as strong as between the previous pair.

References

  1. Driscoll, C.A., Menotti-Raymon, M., Roca, A.L., Hupe, K., Johnson, W.E, Geffen, E., Harley, E.H., Delibes, M., Pontier, D., Kitchener, A.C., Yamaguchi, N., O'Brien, S.J., Macdonald, D.W. (2007) The Near Eastern origin of cat domestication. Science. 317(5837), 519-525.
  2. 2.0 2.1 Leyhausen, P. (1988) The tame and the wild- another Just-So-Story? In: D. C. Turner and P. Bateson (eds.). The Domestic Cat: the biology of its behavior., Cambridge, England: Cambridge University Press.
  3. Laundre, J. (1977) The daytime behaviour of domestic cats in a free-roaming population. Animal Behaviour. 25, 990-998.
  4. Fagen, R. M. (1978) Population structure and social behavior in the domestic cat (Felis catus). Carnivore Genetics Newsletter 3(8): 276-281.
  5. Dards, J. L. (1978) Home ranges of feral cats in Portsmouth. Carnivore Genetics Newsletter. 3(7), 242-255.
  6. Dards, J. L. (1981) Habitat utilization by feral cats in Portsmouth dockyard. Pp. 30-49 In: The Ecology and Control of Feral Cats. Potters Bar: Universities Federation for Animal Welfare.
  7. Dards, J. L. (1983) The behaviour of dockyard cats: interactions of adult males. Applied Animal Ethology. 10, 133-153.
  8. Denny, E., Yakovlevich, P., Eldridge, M.D.B., Dickman, D. (2002) Social and genetic analysis of a population of free-living cats (Felis catus L.) exploiting a resource-rich habitat. Wildlife Research. 45(4), 405-413.
  9. Ohkawa, N. and T. Hidaka. 1987. Communal nursing in the domestic cat, Felis catus. Journal of Ethology 5(2): 173-183.
  10. Kerby, G. & McDonald, D.W. (1988) Cat society and the consequences of colony size. In: D. C. Turner and P. Bateson (eds.). The Domestic Cat: the biology of its behavior., Cambridge, England: Cambridge University Press.
  11. van Aarde, R. J. (1978) Reproduction and population ecology in the house cat, Felis catus, on Marion Island. Carnivore Genetics Newsletter. 3(8), 288-316.
  12. Pryor, P.A., Hart, B.L., Bain, M.J., Cliff, K.D. (2001) Causes of urine marking in cats and effects of environmental management on frequency of marking. JAVMA. 219, 1709-1713.
  13. Westropp, J.L., Buffinton, C.A. (2004) Feline idiopathic cystitis: current understanding of pathophysiology and management. Vet Clin Small Anim. 34, 1043-1055.