1. Territorial Behavior: Cats are territorial animals, and they may become aggressive when they perceive another cat as a threat to their territory. When your cat meets a new cat, it may feel the need to defend its space and resources, which can lead to aggressive behavior.
2. Fear and Anxiety: Some cats may react to unfamiliar cats with fear and anxiety, which can manifest as aggressive behavior. A cat that is feeling fearful or threatened might adopt an aggressive posture, hiss, arch its back, or even swipe or bite to defend itself.
3. Lack of Socialization: Cats that have limited experience with other cats or that haven't been properly socialized may not know how to interact appropriately. This can lead to misunderstandings and conflict, resulting in aggressive behavior.
4. Past Negative Experiences: If your cat has had negative interactions with other cats in the past, it may associate meeting new cats with those unpleasant experiences. This can condition the cat to respond aggressively towards any new cat it encounters.
5. Health Problems: In some cases, a sudden change in behavior, including aggression, can indicate an underlying health issue. If your cat is showing signs of aggression that are out of character, it's important to have them checked by a veterinarian to rule out any medical conditions.
6. Redirected Aggression: Sometimes, cats may display redirected aggression, which occurs when they feel stressed or frustrated and direct their aggression towards something or someone other than the actual source of their annoyance. If there was a stressful event or situation around the time your cat met the new cat, it could be the underlying cause of the redirected aggression.
To address your cat's sudden aggression, it's essential to identify the underlying cause and take appropriate steps to mitigate it. In most cases, gradual socialization, creating a positive and stress-free environment, and addressing any potential health concerns can help improve the situation. If the aggression persists or escalates, it's advisable to consult a veterinarian or a certified animal behaviorist for guidance and professional assistance.