How to Stop a New Cat From Being Aggressive to Other Cats In the Home

Much like humans and dogs, each cat has its own peculiar personality. When introducing a new cat into a home that already has cats, you must be prepared for potential kitty personality clashes. According to Ron Hines, DVM, Ph.D, the typical issues between new cats and other cats who have lived in the home are territorial and hierarchical. A new cat may be intimidated by its new home and feline family and want to hide. However, some new cats will act on their fear by being aggressive to the other cats and vice versa. This behavior can be curbed.

Things You'll Need

  • Separate rooms
  • New litter box
  • New feeding and water bowls
  • Tuna juice
  • Veterinarian
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Instructions

    • 1

      Introduce your new cat to the other cats slowly. Before you bring your new cat home, prepare its own litter box and feeding supplies in a room separate from the other cats' supplies. The new cat's aggression will be eased if it doe not have to fight the other cats for food and space. When you bring your cat home place him in this room with a door that has room enough for cats to slip their paws underneath and close it. If you have already introduced your new cat to the others and they are not getting along, separate the new cat to its own room with its own food and litter box.

    • 2

      Allow the other cats to interact with the new cat from underneath the door. Sensing each other and playing with each others' paws before seeing each other will help ease the cats' instinctual reaction to have territorial and hierarchical guards against each other. This step may not guarantee an automatic friendship between the cats, as their ages and personalities still play a factor in whether or not they will get along. After a full day of the new and old cats being aware of each others' presence and interacting with their paws, open the door and allow them to meet each other.

    • 3

      Observe the new and other cats' behavior carefully. The previous steps should have lessened the aggression in both the new and other cats but they may still fight. When felines wrestle playfully with each other there should be no hissing or growling and their ears should not fold down to their heads. Any of these is a sign of serious aggression and the cats should be immediately separated from each other.

    • 4

      Identify the most aggressive of your cats between the new and the old. If your new cat remains dangerously aggressive to the other cats in the home it may be time to see a veterinarian. According to Pamela J Reid, Ph.D., ASPCA, cats can be prescribed a low dose of diazepam--a drug to moderate their aggressive behavior. However, as an alternative to drugging your cat, she advises rehoming the new cat rather than continuing to put both the new cat and your old cats at risk.