The question in the title should be extended to feral and stray cats and the answer is the same in any case.
The root cause of the majority of domestic cats fighting is a defence of their home range. The ‘home range’ is the territory which they consider their own. It is interesting in that we often hear about tigers fighting over their territory and we understand it because tigers are ferocious and large and we expect them to fight to protect their patch of ground. But domestic cats have exactly the same feelings and behaviours.
However, the difference between domestic cats and tigers is that the domestic cat has become very flexible and adaptable in what they expect to have in terms of space as their home range. It is this flexibility which avoids fights together with scent marking i.e. urine spraying on vertical objects and sometimes other forms of marking. These scent markers allow domestic cats to avoid each other when outside because they can work out when and where the other cat was at that location.
Domestic cats don’t want to enter into a fight unless they really have to because in addition to scent marking which avoids confrontation you will note that when they square up to each other as a preliminary to a fight it’s a bit like sumo wrestlers. The both have body language which is meant to warn off the other. If the dispute can be resolved this way because one of them slinks away, they avoid a fight and nobody gets injured. Injury jeopardises survival in the minds of domestic cats.
So, there are several ways of avoiding fights to which we have to further add the neutering of male cats. When male cats are sterilized, they have no means of production of testosterone which reduces aggression which in turn helps to eliminate fights. They do still fight but less so and therefore they are injured less often. This is always said to be one of the major advantages of neutering male cats.
What mitigates the possibility of male cats fighting in multi-cat households especially when they are full-time indoor cats is that there is a constant provision of food which helps to make the cats more cooperative in the interests of survival. But occasionally fights might break out because there’s this instinctive, inherited desire to live in 150 acres of land which is suppressed artificially by living in the human world.
I’ve seen videos of interior of the homes of cat hoarders and rescuers where there might be 100 cats in a two-bedroom apartment and they all appear to get on because they have to. The alternative is to be cast out into the freezing cold. I’m referring to a video I saw of a Russian lady who rescued cats. Lots of the cats were white because they were breeding but they won’t fighting. The provision of food and warmth kept them cooperative.
However, the more compressed a group of cats is, the more likely that a fight will erupt over territory. For instance, in a multi-cat household one of the great problem areas is antagonism between cats. Cats in multi-cat households will have a tiny fraction of the space that their wildcat ancestor has to enjoy.
Size of home range
It is said that the wild counterpart of the domestic cat has a huge territory with males patrolling up to 175 acres. Farm cats might range over 150 acres and consider that to be their home range. In Australia their feral cats have many square kilometers of space to call their own and they’ve become much large as a consequence. Domestic and feral cats expand into more space when allowed. I believe that indoor/outdoor cats settle on around 4 acres as their home range.
Male cat home ranges usually incorporate the home ranges of female cats as is the case, incidentally, with tigers. It’s a bit like a harem for the male cats. Their territories are always about 10 times the size of those of the females regardless of how great or small the crowding. Male ranges also overlap as do female ranges. Each male will roam about his home range to keep a permanent check on which particular queen (female) is on heat at any particular moment.
And it depends upon the character of the cat. Some cats are more dominant than others. They are more confident. If there are two dominant male cats in a multi-cat household they might fight. I’ve constantly referred to male cats because it is males who tend to fight a lot more than females.
Spaying and neutering
Of course, the females are also sterilised through the spraying operation so they won’t go into heat but this instinctive behaviour from the males is nonetheless present.
Instinctive behavior versus modified behavior
The overall picture is somewhat complicated because you have this instinctive wild cat behaviour which drives domestic cats which is set against sterilisation, adaptability, flexibility, the provision of a food source and security and warmth which pacifies them.
Revert to wild cat behavior
All of these sorts of questions about domestic cat behaviour reverts to their wild cat ancestor. In fact, when you answer questions about domestic cat behaviour you always revert to the behaviour of the North African wildcat, the domestic cat’s wild counterpart. If you want to understand the family cat behaviour look up the behaviour of this wildcat and you get all the answers that you want.
Kittens wrestling – fight over queens – siblings fighting
I have to add three postscripts which is that you often see kittens fighting depending upon their character. I remember seeing a bunch of F2 and F3 Savannah cat kittens raucously fighting in between sleeping in a hammock. It sounded painful but this was a learning process. It was having fun while at the same time fighting and even hurting each other. They learned that they were hurting another cat when the victim complained. But fighting is inherent. There is an overlap there too in predation because predation is a formal fighting not with other cats but with prey animals.
Secondly, male cats can fight over access to a queen for mating. And thirdly, sometimes siblings fight when they become adults. When they are kittens they are passive towards each other but when they become independent which would normally lead to them looking for a home range, they might fight each other as if they were strangers. This probably harks back to the essentially true concept that domestic cats are solitary. It doesn’t matter if one brother knows another brother because they were raised together as kittens. Once they are adults, they are a couple of independent cats with a wild cat temperament at the heart. It is the raw cat in them which Jackson Galaxy always refers to when discussing cat behaviour.
Ferals fight to death
You will see male feral cats fighting in the most vicious way with each other over territory. And sometimes a fight to the death. You will see videos of this on YouTube.
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