Dr Liesel van der Merwe is a small animal medicine specialist. Send her your questions: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Dr Liesel van der Merwe

Cats are generally solitary rather than group animals. Think of nature – lions are the only felines that live in a family group. The other large cats only meet up for mating and the mother looks after the cubs until they are able to fend for themselves.

Feral cats sometimes form colonies, and often interact with domestic cats. But even in colonies, it is important for each cat to have his or her own defined area. This area can be subdivided into two distinctive parts: home range and territory.

Range
The home range is the area in which the cat lives, and the territory is the area he or she defends. The territory is normally smaller than the home range. There are also two kinds of home range: a smaller ‘24 hour’ home range and a long-term home range, which is much larger.

The size of the home range varies with the habitat and the availability of food, but there are some defining features: male cats have a home range about 10 times larger than that of female cats.

Female cats’ ranges clump together, normally around a building or other place of shelter and often overlap. A male may include the ranges of a number of queens in 'his' range. The male normally moves on the outer parts of his home range and the greater the availability of food the smaller the home range.

Property
Our modern, denser style of living is conflicting with this pattern. Cats are considered easier pets than dogs in that they are small, independent and generally need less one-on-one time and are thus seen to be suitable for small properties and working owners.

This, however, will often bring cats from different households into too close proximity to each other.

House cats which are allowed outside will establish their home ranges and territories. The home range for female house cats is only about 0.05 acre, which is approximately 200 m² and usually includes her own garden and adjoining gardens. These ranges are small because the cats are being fed, so food source is not a problem.

Interestingly house cats never create colonies with neighbouring cats; if they meet it is more to assert their territorial rights. Incursions into the long-term home range by strange cats are more tolerated than into the smaller home range. Incursions into the cat’s territory cause stress.

Introduction
Introduction of new cats – even into your own home – can be fraught with problems and cause inter-cat aggression, usually transient, but often quite severe. It requires gradual introduction and behavioural management and may even require medication. This is obviously not going to happen when a new cat moves into the neighbourhood.

There is a constant movement in a neighbourhood cat population. In this case I believe it is important to firstly ensure that your cat’s territory is strongly protected. Secondly, make sure that your cats are not a nuisance to the neighbours.

Try to prevent other cats from entering your property. Having a dog helps with this. If you don’t have a dog, then you can string fishing line tightly about 5-10 cm along the tops of your walls. This will make it awkward for cats to jump onto the wall.

Closed
Don’t have a source of food available to visiting cats. When I was living in a complex my motto was that the house was closed and cats were either in or out when I was out; and the house was closed and cats were in at night.

I placed mesh on the windows to allow them still to be opened. Free access in and out was only allowed when there was someone at home. This greatly reduced territorial invasions to find food, reduced stress on the more submissive cats, reduced urination from stress and territorial marking inside the house and allowed me to sleep at night, knowing my cats weren’t involved in fighting.

Flaps
Cat flaps with built-in receivers can allow access to only your own cats, who will be wearing collars with little transmitters. This allows free access into your home and the food source at all times for your own animals.

Cats which are stressed will often start showing behavioural changes and may develop medical conditions such as interstitial cystitis, which are treated with environmental modification to remove stressors.