Living in harmony with two or more cats in your home can be a rewarding experience. But when one feline starts to urinate outside the litter box, it can anger the most loving cat owner and prompt an eviction to the nearest animal shelter.
Veterinary surgeon and animal behaviourist Cynthia Smillie, at the Animal Behaviour Veterinary Practice, offers helpful advice on how to notice the signs and deal with problems associated with multi-cat households.
'Most owners only become aware of a problem between cats when they start spraying around the house, or there's aggression to other cats or to the owners,' Smillie says. 'Often, most people don't attribute inappropriate urination to problems between cats. Unfortunately, they don't understand a cat's social structure.'
While dogs are pack animals and usually exist within a social group in the wild, Smillie says cats are mainly solitary hunters. And while social groups of related cats can live together, their social structure is vastly different to dogs.
'A lot of problems can arise when we ask unrelated animals to share a core territory,' explains the former deputy director of the Society for the Prevention of Cruelty to Animals Hong Kong. 'The cats need to feel safe and secure, and there is the potential for conflict when one cat comes into contact with another.'
According to Smillie, most of a cat's behaviour is geared towards patrolling its territory and marking it with urination, faeces or scratching. When a territory overlaps, another cat will assess the markings of a foreign cat. 'They will suss out if another cat's marks have faded over time, which signals 'I have not been here for a while', then they might put out another signal - it's all about avoiding conflict and aggression.'
When it comes to urinating outside the box, Smillie says, 'the cat is saying: 'I'm very stressed and spraying is a way for me to feel more comfortable'. This makes the cat feel more secure in its core territory and also signals to other cats to keep away.'
Cats do not naturally share their resources. However, in a domestic situation, Smillie points out that owners expect their furry felines to share the same food bowl and resting space.
Sometimes, there are separate food bowls for different cats, but the bowls are in such close proximity that it can cause conflict.
Sharing a litter tray is another potential hazard to avoid. Smillie says that some cats will happily share their litter tray with a fellow feline but, as a general rule, it's best to have one tray per cat, plus an additional tray. Therefore, if you have two cats, your home should have three litter boxes.
She says: 'They may decide to share, but it's all about giving them options and not forcing them to share.' With limited space in most apartments, the minimum number of litter boxes should be one per cat, Smillie says.
'The problem in Hong Kong is that most cats are confined indoors 24 hours a day. And their general frustration increases if they can't exhibit normal behaviour such as hunting and exploring territory, along with additional stress that can be caused by issues between cats,' Smillie explains. 'If they don't have an outlet, like going outside, people need to provide environmental enrichment.'
To keep your cat entertained, the veterinary behaviourist suggests playing games that simulate hunting, such as fishing toys or a laser pointer. Providing a choice of safe resting places, whether it's a high space for a cat to jump onto or a low-level bolt-hole, is another way to help alleviate tensions between frustrated felines.
'People assume their cats are getting on well, but one cat can subtly start acting one way to make the other feel uncomfortable,' Smillie says. If there have been additional stresses, such as moving house, adding another cat, a new baby or renovation work, this can be the tipping point.
'Some people will notice one cat being aggressive to another cat or other family members. These are the signs that a cat isn't happy. We really expect cats to live together, but in the wild they would not live that way. It's completely unnatural to their social structure.'