Cats establish relationships based on their control of territory and not a dominance hierarchy. Cats protect territories for themselves and their families large enough to supply the family with food and shelter. The size of the territory is influenced by the number of cats sharing the area and characteristics of the cats themselves. Female cats are likely to share territories with their mothers, female siblings and offspring and are comfortable in a smaller territory than males.  At about 8-10 months of age, young male siblings begin fighting and a few will disperse to new areas. 

Cats identify their territories with scent marks. Scratching with their claws, cats leave scent marks and get exercise that keeps claws healthy. Cats also leave scent marks by rubbing their cheeks on prominent items in the territory. When territorial disputes occur, many cats mark the borders of their territory with small amounts of urine. This can be a problem if it occurs indoors. Setting up sub territories inside the house to reduce contact between cats, helps. Keeping litter boxes clean, accessible and attractive to the cat will also help prevent litter box avoidance which contributes to elimination problems.  

Behaviorists believe that cats can tell what time territorial scent marks were left and can tell who left the mark if the marker is known to them. If the mark is from a stranger, cats may be able to detect information about the cat who made the mark such as his breeding status. This allows cats to travel through a territory avoiding confrontations. This also allows cats to meet up for breeding. The stronger cats will be able to choose their own schedule and other cats will work around them. As long as the area is large enough, confrontations are minimized by keeping the schedule. Confrontations between cats may still occur with newcomers who are learning the routine or with those who wish to challenge the existing order. 

Indoor cats can run into problems avoiding each other which leads to misunderstandings. One cat may bully another for failing to leave the area when the other has no choice. Using magnetic cat doors (which open only by a cat with a key-collar) can set up sub territories and solve this problem. Separating cats within a household can do the same if it’s feasible. Having multiple litter boxes and elevated perches may also work if the cats cannot be separated. Plenty of individual attention and exercise helps, too.