It is normal behaviour for cats to use urine marking as a means of communication. However this urine marking becomes inappropriate when it happens inside the house, or for inappropriate reasons such as excessive anxiety or excitation.
What is spraying?
When a cat is spraying they will approach a vertical surface, turn around and stand with straight legs, their tails up and sometimes flicking from side to side. A small jet of urine will be sprayed backwards onto the surface and the cat will move off. They often do not scratch and do not squat.
Who does it?
15% of desexed cats, both male and female, spray urine. Spraying and marking behaviour can change when cats routines are interrupted, such as increased stress from moving house or where new cats have entered the home or neighbourhood. Even for desexed cats, spring and summer are when there is increased activity of other cats in the area, often leading to increased anxiety.
Cats in multiple cat households are more likely to spray.
Why do they do it?
Urine contains pheromones, these are natural chemicals that are used to communicate with other cats. The pheromones in urine are used to express stress. They are usually sprayed to let other cats know that they are on already controlled territory and to alert them to the fact that they are in an area that is not secure or that they feel stressed in.
You have probably also noticed your cat rubbing their face against objects and yourself. There are facial glands that produce pheromones that express happiness and well being. Cats like to mark their environment this way because the facial pheromones make them feel secure that they are in a familiar area where they feel happy and safe.
Can this lead to other problems?
Yes. Excessive stress can precipitate disease such as Feline Lower Urinary Tract Disease (FLUTD), cystitis or gastrointestinal upsets. Cats can also go off their food if stressed.
What can we do about it?
There are several options to correct inappropriate urine spraying, not all can be done by the vet!