Domestic cats are not adapted to living in close proximity to each other

The title presents an interesting thought and it directly impinges upon what goes on in multi-cat households. Although domestic cats are social creatures and they can live in groups those groups need to be stable and the cats should be socialised to each other. In other words, the cats should be selected to get on with each other and ideally no new cats should be brought into the group which might destabilise it.

Domestic cats are not adapted to living in close proximity to each other. Montage: MikeB from images in the public domain.

Domestic cats don't have classic hierarchies when living in groups and they don't have signals which help to defuse conflict. Further, they don't have mechanisms such as reconciliation as discussed in studies by van den Bos & de Cock Buning 199b and van den Bos 1998.

In the wild, if there was conflict between cats, they would disperse to avoid each other and often this is impossible and in multi-cat homes and it certainly is impossible if they are living full-time inside a home. This is exactly what is happening with my neighbour about 4 yards from me right now. She has 10 cats and she hasn't got a clue as to what she's doing in terms of how the cats feel when they live in such close proximity to each other as far as I can tell.

One of the major reasons for the creation of behavioural problems in domestic cats such as timidity, fear and avoidance behaviours come about because of what is called environmental stressor i.e. things that happen in the environment in which they live which stress the cats. A high proportion of the stressors are concerned with the relationships between the cats and the relationship between the cats and people living in the home. This was found in a study by Casey and Bradshaw in 2000.

Sibling pairs of domestic cats more often have amicable relationship compared to unrelated cats when living together. Although, I think it is fair to say that not all siblings get along when they become adults because at that time they become independent. It's just that there is a greater likelihood of the siblings getting along in multi-cat homes.

A point comes to mind. Jackson Galaxy says that when you adopt a cat from a shelter you might adopt a pair if the shelter knows that they are known to get along. I guess that makes sense but not infrequently cats are rescued as a pair and then they are rehomed as a pair for obvious reasons. When two cats get along well, both their lives are enhanced and they should stick together. It is not only better for the cats it is also better for the cats' caretaker because they can entertain themselves and enrich the lives of each other.

When cats are introduced to each other as adults they may not regard each other as part of the group but they are sometimes regrettably forced to live together in close proximity which may lead to agonistic behaviour. 

Aggressive encounters may occur not infrequently between cats living in a high density in the neighbourhood. I'm referring to indoor/outdoor cats. This is a typical situation in the UK for instance. Under these circumstances some cats may become frightened of going outdoors. The other, more dominant cats will be attacking the timider cat when in a public area.

It is wise for cat owners particularly in condominiums and blocks of flats to be aware of this interaction between cats in the common parts within these complexes.

Ref: Cat Sense by Dr Bradshaw.