What do I need to know about multi-cat households?

With approximately half of cat-owning households caring for two or more cats [1], it is crucial to recognise that keeping multiple cats, while fundamentally similar to keeping a singular cat, requires a good understanding of cats’ social needs and behaviour. Whether you are thinking of getting another cat or already have multiple fur friends, understanding feline social groups, providing adequate resources, and recognising and managing signs of intercat tension are key to an ideal multi-cat household that maximises welfare while minimising stress for all.

Understanding cat behaviour and recognising feline social groups

Cats have flexible social systems and have their own preferences in how they want to interact with other cats, animals, and humans, which can be dependent on their social dynamics, environment, and past experiences [2]. This means that they are not strictly solitary animals but also do not necessarily need other cats as companions. Some cats seek out social interactions more than others, some like to spend time with other cats in a social group, while some prefer to be alone.

Companion cats usually have no choice about whether they share their home with another cat or which cats they live with (compared to unowned or semi-owned free-ranging cats). The ability to adapt to a multi-cat household depends on a range of factors, from those related to the cat such as personality, age, sex, genetics and sterilisation status, to factors associated with the owner and the environment [3]. In some cases, cats may gradually learn to coexist, while in others, they may remain incompatible. Patience is very important, if cats are going to get used to sharing their home with another cat, they need time to adapt during the transition period; how much time depends on the individual.

Understanding feline social groups is important in helping owners understand the cat dynamics in their household and how to manage these to optimise the environment for their cats, including allocation of resources and monitoring cat relationships. A feline social group consists of cats who have defined and recognisable social bonds. Cats in a social group show affiliative behaviours (friendly behaviours that form and reinforce social and emotional bonds with others) such as mutual grooming (allogrooming), rubbing against one another (allorubbing), sleeping in close proximity, or playing together [4]. If you want to learn more about your cat’s behaviour, this guide has more information on their emotional and behavioural responses and body language.

Having to share space or resources with other cats can cause significant stress, especially if the cats are not part of the same social group. It is important to note that simply living under the same roof does not automatically mean that cats will form a social group and there may be more than one social group within the household.

Transitioning into a multi-cat household

Before deciding to introduce a new cat into your home, there are several factors to consider. Firstly, you need to assess the individual needs and preferences of your existing cat(s), keeping in mind that not all cats will have the same needs. Additionally, assessing whether you will be able to meet the needs of every cat in the household, including the new cat, is important when considering the logistics and practicality of getting a new feline member.

Upon adoption of a new cat, it is important to make sure the cats are introduced in a way that maximises the chance of a successful and happy multi-cat home. While many cats can learn to live together peacefully, it is important to remember that a harmonious multi-cat household is not always guaranteed. However, good preparation and safe gradual introduction can make a difference by decreasing the risk of future problems associated with cohabitation. Overall, the process of bringing a new cat into the house should be a gradual one (weeks to months) and be at the pace of the cat. You can find more information in this article, including a step-by-step guide on how to safely introduce a cat to existing cats.

Creating a cat-friendly environment: Five Pillars

The Five Pillars of a Healthy Feline Environment act as the foundation in creating a cat friendly environment. Fulfilling these environmental needs is essential for all cats, as it supports their physical health, emotional wellbeing, and ability to express natural behaviours like exploring, scratching and pouncing [4].

• Pillar 1: Provide a safe place
• Pillar 2: Provide multiple and separated key environmental resources
• Pillar 3: Provide opportunity for play and predatory behaviour
• Pillar 4: Provide consistent and predictable human-cat social interaction
• Pillar 5: Provide an environment that respects the importance of the cat’s sense of smell and other senses

For more information on creating a cat-friendly environment, see RSPCA’s guide to keeping your cat safe and happy at home.

In multi-cat households, ensuring the five pillars are fulfilled is critical, as resource competition and intercat tensions can arise if the environment is not carefully managed. The introduction of a new cat can impact the five pillars in a range of ways, for example:

• Firstly, a new cat may intrude into the existing cat’s personal space, disrupting their sense of security (Pillar 1).
• If resources such as food, water, litter trays, hiding and resting areas are not increased and properly distributed, direct competition may arise (Pillar 2).
• The social dynamics of the household can also shift, with some cats engaging in unwanted predatory play directed at others (Pillar 3).
• With an additional feline companion, each cat may receive less human attention and changes in daily routines could affect their sense of stability (Pillar 4).
• The introduction of new scents and unfamiliar noises from the newcomer may cause distress to the resident cats, disrupting their sense of familiarity in the environment (Pillar 5).

Understanding these potential challenges with the introduction of a new cat allows owners to take proactive steps to help minimise stress and foster a peaceful multi-cat household [4]. For more details about the respective pillars, refer to this section of the guide, which not only explains the importance of each pillar but also how to adequately provide for these needs.

Providing adequate resources and understanding spatial dynamics

Essential resources include food and water bowls, litter boxes, scratching posts, resting places, and hiding spots. As a rule of thumb, in the house, there should be one resource for each cat plus one additional in separate locations to allow for choice and prevent resource guarding [5]. For example, if you have two cats, you should have at least three litter trays, three food bowls, and three water bowls, all placed in physically separated locations (ensuring that food, water bowls, and litter boxes are distant from each other). In addition, to avoid causing stress to your cat, food should also be out of sight from other cats’ bowls.

Competition or conflict over shared resources can cause significant stress for cats in multi-cat households. For instance, tension can occur when one cat blocks another from accessing essential resources, such as litter trays or resting spots [6]. This can be minimised by having multiple and separated resources distributed around the house.

Each cat’s home environment comprises of three areas – home range, territory, and core territory (refer to the box below). Ideally, each social group should have its own core territory, containing essential resources such as food and water stations, safe places, and play areas. Understanding these spatial dynamics helps owners arrange the home to create multiple resource stations, maintain separate core territories, while respecting each cat’s need for security and autonomy [4].

Home Range: The total area a cat regularly explores and patrols, includes both indoor and outdoor spaces

Territory: The subset of the cat’s home range that the cat actively defends from unfamiliar cats or perceived intruders

Core Territory: The most secure and frequently used area within the cat’s territory, where the cat eats, sleeps and plays.

Recognising and addressing intercat tension

Intercat tension is a real concern in multi-cat households, yet it can often be subtle and go unrecognised. It often occurs because there is competition over resources or a change in the environment that shifts the relationships between cats. The introduction of a new cat is a very common trigger for the development of intercat tension, but it can also be associated with other triggers such as the reintroduction of a resident cat who was away for a period, territorial invasion by an unfamiliar cat, or underlying medical issues [1,7]. The problems related to intercat tension include a negative impact on cat wellbeing, behavioural issues (e.g., cat-cat aggression, aggression towards owners), elimination problems, and stress-related illnesses (e.g., urinary tract disease, excessive self-licking) [6].

Given that intercat tension can negatively impact cat welfare, owners are encouraged to learn how to recognise intercat tension for early intervention. Signs of intercat tension range from subtle behaviours like staring at the other cat, marking (e.g., urine marking or scratching furniture), tail twitching, blocking the other cat from passing or accessing resources or hiding, to more overt signs such as hissing, chasing, and physical fights. Even behavioural changes such as inappetence and disturbed sleep can be signs of tension [4,7].

Upon recognition of intercat tension within the household, it is important to seek veterinary assistance to rule out medical problems and get advice. It may be helpful to note any recent changes in the environment, resources, routine, or social interactions to discern the source of conflict.

It is important to assess the cats’ environment and ensure that you have done everything possible to meet all of the cats’ needs (see the five pillars of a healthy feline environment above). Providing additional resources, rearranging the environment to increase space, and the use of synthetic feline pheromones can all help manage the situation.

If you have identified specific triggers for the intercat tension, if possible, take specific preventative measures (e.g., if a neighbourhood cat’s presence around your home is triggering tension between your cats, taking steps to ensure your cats cannot see cats outside). If tension occurs at any stage during introduction of a cat, it is advised to halt the process and go back one step before re-attempting. In some cases, specialist veterinary behavioural guidance may be necessary to help rebuild positive relationships between cats [4].

Summary

With careful observation, thoughtful environmental design, and proactive management, it is possible to create an environment that maximises the chance of a successful and happy multi-cat home. If you are keen to learn more about other aspects of cat husbandry, the RSPCA Guide to Keeping Your Cat Safe at and Happy at Home is the resource to go on how to help all the cats in your household be safe, happy, and healthy.