Help! My new cat is not getting along with the other cats in the house! I have heard this plea from owners and have dealt with this issue in my own household.
It is not uncommon to see some degree of aggression between cats in the same household, especially when one cat is new to the group. When we address any form of inter-cat aggression, It is important to remember that cats are not social creatures and do not live in large packs in the wild the way dogs do. They are often very solitary and hunt on their own. Thus, having more than one cat in a household is automatically not compatible with their natural behavior. However, there are many cats that form social groups within their home territory and co-exist peacefully.
When there is a new cat to the household, there can be many different underlying causes of the aggression. The most common factors are fear and the sudden increased competition for resources (food, resting places, owner attention). Cats also strongly rely on scent as a means of social communication. When cats rub (allo-rubbing) or groom each other (allo-grooming), they are actually swapping scents and forming a unique group scent. When a new cat comes into the house, this cat does not smell like the group and thus the existing cat may show extreme aggression towards this cat as it represents a threat to the group resources.
With treatment, the ultimate aim is to produce a fully functioning social group in which there is minimal aggression. Treatment consists of a combination of modifying the environment to meet the needs of the cats and to successfully introduce the new cat to the household with a very gradual process. To help reduce any perceived competition of resources, the number of litter boxes should be increased. Each cat should also have its own water and food dish located in a separate part of the house. It is also important to make sure there are plenty of places for each cat to escape, as a cat’s primary means of controlling interaction with other cats is to maintain distance. Don’t forget about vertical areas as well (such as cat towers).
When introducing new cats, there are several steps that should be taken slowly to maximize the potential for success. To begin, the new cat should be kept separately in a room with its own litter box, food/water dishes and toys. Step 1 consists of taking a cloth and rubbing one cloth on each cat (especially the face). This is to collect the scent from each cat. Then each cat should be presented with another cat’s cloth when going to greet, feed or play with either cat. There may be an initial aggressive response, however, over time the cat should ultimately ignore the odor or react positively. Once this occurs, you can move on to Step 2.
Step 2 consists of taking the cloths with each cats scent (freshly rubbed against each cat) and putting the cloths in a bag so that the odors mix. Then introduce this combined odor to each cat. Once there is a positive response, then rub this mixed odor on your legs and other objects that the cats typically rub against. Once the cats are accepting this new combined odor, then you can move to Step 3.
For step 3, the new cat should be allowed to explore the house while the other cats are excluded or shut in an inaccessible room. Once the cat is acting confident in the house, then the cats need to begin to see each other but without any risk of an aggressive attack (Step 4). You can use a baby gate or some other form of barrier between the cats. They should be given food on either side of the gate and the food should gradually move closer to the screen. Once they are showing no aggressive or fearful behavior, they can be allowed to meet face to face.