Multicat households and aggression - Veterinary Practice
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Multicat households and aggression

Sarah Endersby of Ceva examines the various considerations for pet owners in multi-cat households and how to deal with signs of aggression effectively.

MULTICAT HOUSEHOLDS ARE ON THE RISE with an estimated 44% of feline households having more than one cat. Intercat tension can impact on the welfare of cats in the home and a UK study found of those cats relinquished to rescue centres due to behavioural problems, aggression between cats was the biggest problem reported.

Although cats are solitary hunters, they are capable of living in social groups in the wild; usually related females and their offspring with group size related to the availability of resources. Cats within a social group usually demonstrate little conflict; however, aggression is displayed towards outsiders and it can take a long time before any outsiders are accepted.

When conflict does occur, reconciliation is limited. Instead cats prefer to flee or avoid each other, as fighting could result in an injury (and in the wild this could affect their ability to hunt), but if these options are not available or don’t work, overt aggression is a last option.

In multicat households the cats often are not related, have to share their resources and have limited opportunity to hide or avoid situations of potential conflict. It is understandable why conflict can occur in these households.

What are the signs?

Some “aggressive” behaviours are normal for a cat, as they can be part of hunting or play. Play fighting involves chasing each other, rolling around and batting each other with their paws. It is generally silent, with any biting being gentle and claws are usually retracted. Videoing any day-to-day interactions between cats can be helpful  to understand cat relationships in the home.

Active aggression can be easy to spot, such as hissing, swiping paws and chasing. Other signs which might be harder to spot are passive conflict signs such as staring, sitting in front of resources to block access and keeping a distance from one another.

Why do we see aggression other than due to sharing resources?

Episodes of aggression can occur when owners are ill-prepared, e.g. when one cat returns from the vet hospital; the familiar communal odour that bonds the group is changed with the addition of threatening smells.

To avoid this the returning cat should be kept in a separate room initially for at least the first 12 hours (or overnight) to enable it to groom to re-establish a familiar odour. You can assist this process by stroking and using a pheromone diffuser (Feliway Classic).

Cats have a keen survival instinct, which means that re-directed aggression can be triggered by the sudden sound/movement of a cat seen through a window; the attack just happens to be towards the innocent housemate that happens to be there. Relationships between these two cats may be irretrievably damaged under these circumstances.

What can we do about it?

If the primary trigger can be identified then the first step is to remove this, e.g. if tension between cats in the household is present then looking at the environment and resource management will help.

Sometimes we have to remember that the cats may be incompatible and living together is actually not in their best interests. This can be a difficult conversation to have with the owner but may be the best option for both the cats and the owner long-term.

All “cat resources” (feeding areas, water bowls, litter trays, beds, toys, scratching posts, high places to rest and private places) should ideally be provided in the formula “one per cat plus one extra” and positioned in different locations so all cats in the household have access without a need for interaction with others in the home.

If there are several social groups within the home and space is limited, the formula may be revised to “one per social group plus one extra”.

  • Eating is a time when cats prefer to be alone – position the bowls so that each cat can eat without having to turn their back on a cat they do not feel comfortable with. Placing food in the multiple feeding stations allows cats to decide on the appropriate time to feed.
  • Even if the cats have access outdoors there may be competition outside, so it is wise to provide indoor litter facilities where they may feel safer. Ideally access to outside should be via two separate points to prevent guarding – this can be via a variety of cat flaps, windows, doors, etc.
  • Scratching posts should be provided as cats like to scratch in areas where other cats are as a means of communicating territorial rights.
  • Cats like to watch what is happening from “up high” as they feel safer this way. Allow adequate access to these spots as well as private spots when a cat can rest away from potential attack.

If cats are physically fighting then it is important to avoid injury to either the cats or the owners using a distraction (such as a toy) or barrier – rattles or water pistols can actually increase tension and aggression and are not recommended.

Once the cats have been separated, it is best to keep them in their own area with all of the resources they need for a period of time. Owners should then consider discussing the issue with their vet or behaviourist.

While separated, introducing each cat to the other’s scent and facial pheromone is a great way of them “meeting” in a non threatening way. The facial pheromone communicates a positive message of security and familiarity and is easily collected using a cloth which is stroked around the head of one cat.

This cloth can then be rubbed against doorways and furniture in the area the other cat is in and left for the cat to investigate. Repeat this for the other cat. Having a facial pheromone diffuser (such as Feliway Classic) plugged in the area of each cat can also facilitate the feeling of security.

The cats can then be slowly reintroduced together, first visually and then with decreasing physical distance between them.

Owners should be prepared to take this introduction process as slowly as required for the cats and to understand that the cats may never want to spend time in each other’s company.

Now there is a new product available for owners who have cats that display conflict in the home. The cat-appeasing pheromone is released by a queen when she is nursing her kittens to encourage a feeling of safety for them and also a bond between them.

A synthetic copy of this pheromone (Feliway Friends) is available as a diffuser which should be plugged in the area where cats spend most of their time (usually where they sleep) and has been shown to reduce signs of aggression between resident cats.3

We can never assume cats will be best friends, but it is important to help those within a multicat household to accept living with others without feeling threatened by their presence.

Careful introduction of new cats into the home can help alongside ensuring enough resources are spread out throughout the home for each cat to access individually (further information can be found on the International Cat Care website).

Owners should also consider training their cats to accept handling, grooming them and being picked up.


1. Source: Insight Track 2014.

2. Casey et al (2009) Reasons for relinquishment and return of domestic cats to rescue centres in the UK. Anthrozoos 22: 347-358.

3. De Porter et al (2014) Evaluation of the efficacy of a new pheromone product versus placebo in the management of feline aggression in multi-cat households. Proceedings of the ACVB/AVSAB Veterinary Behaviour Symposium, 17-18.

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