Sudden Unexplained Aggression in Cats

Cat aggression "is the second most common problem" seen in cats, according to the American Society for the Prevention of Cruelty to Animals. Aggression from your cat can be directed towards another animal or towards a person. Sudden aggression in your cat can become potentially dangerous, especially if your cat uses biting and clawing. If your cat becomes aggressive when it was once a docile animal, see your veterinarian to understand possible causes.

  1. Pain-Induced

    • Cats can suddenly adopt aggressive behaviors due to medical conditions. If your cat is hurting, it may anticipate your response of picking it up and swipe at you to leave it alone. Cats can also associate pain with past trauma. For example, if your cat got its tail accidentally caught in a door, it will remember the pain associated with the experience. If you try to pet your cat near its tail, it can suddenly attack in an attempt to prevent any "pain" from occurring to that area.

    Unknown Smells

    • Your cat can pick up smells at the vet's.

      Unknown visitors into your home can cause your cat to react negatively, according to the Cornell University College of Veterinary Medicine. If your cat hasn't become accustomed to new people and doesn't know their smell, your cat may react with aggression. If you own multiple cats, take one to the veterinarian and bring it home, your other cats may suddenly hiss, growl and bat at the other cat. The cat who visited the veterinarian will smell differently, causing your other cats to respond negatively.

    Over Stimulated

    • Cats can respond to over-stimulation through acts such as petting and redirected aggression. While your cat may seek you out for affection, once it decides that it's had enough, it may bite or scratch. Your cat may even fall asleep through petting but suddenly wake up. It may bite upon awakening as an instinctive response because it's not aware of its surroundings, according to Pet Education. A cat may also bite when it's distracted from its stimulus. For example, a cat who sits and watches a bird from a window may suddenly redirect its response towards you.

    Other Causes for Aggression

    • Introducing a new animal into your home can cause your cat to engage in territorial aggression. Your cat may choose to stalk the new animal or immediately attack. In some instances, the exact cause of your cat's aggression can't be identified. This is known as idiopathic aggression, indicates the American Society for the Prevention of Cruelty to Animals. A cat with idiopathic aggression can attack violently and often.