Neither of the cats seeks the other out, but if they run into each other, both will act startled and attack.

When two cats in the household who have gotten along well togeth er suddenly become aggressive toward each other, the problem is generally fear-induced aggression.

I used to see lots of other cats roaming across the high wall that divides the gardens of our street and the one behind, now only psychokitty. Anal gland is fine , no fever, no fleas. However, if we see that a cat is hiding and doesn't want to come out, seems scared of other people or is overly alert to stimuli, it is possible they are in pain. A frightened cat is an unhappy cat in my opinion, but a crazy cat may be perfectly pleased with itself, just not in a way that's comprehensible to people.

If a cat isn’t socialized properly they can be afraid. -Petting-induced aggression, the type described in the opening paragraph, occurs when a cat who enjoys being pet suddenly changes his or her mind.

He does has an injury on his leg he has been licking. The cat is now highly aroused and directs its attention onto the next thing she/he sees. Another cat in the household then enters the room and the cat redirects the aggression to the second cat. For example, a cat sees another cat through a window, but is unable to reach it. My cat is suddenly slinking around the house scared and looking at nothing that I can see. The vet thinks maybe allergies? Cats who growl when you try to move them, block doors, or bite you when you pay attention to another pet may be asserting themselves in this manner. I adopted a kitten who was abandoned by the mother. Also, he is losing fur around his face . I did take him to the vet and she is not sure . A naturally timid cat may be afraid of many things and spend a lot of her life in hiding, while a naturally confident cat will be less fearful and will usually recover more quickly from scary events. Pain and fear are often the reasons for a cat to have a behavior change that results in aggression. For example, one cat may confront a strange dog by hissing, spitting, and puffing out his fur to make himself look big. If they had a bad experience they can be afraid. My cat is scared of another cat & won't go out (14 Posts) Add message ... and has made all other cats in the neighbourhood scared. At the end of the day, if your cat is suddenly behaving in a way that is contrary to what you normally see from it, don’t just chalk it up to a weird cat-ism, investigate it. Also you'd usually see other signs too such as skin twitching/rolling, and the cat suddenly racing around like a bat out of hell. And you probably would've seen signs of it before the age of 2. -- there is also what I scientifically refer to as the Poop Dance; one of my cats would race madly from one end of the house to the other after having used the litterbox. So I'd tend to discount FHS at the moment. A cat that is not normally prey-driven and is hissing, swatting, biting, and overall aggressive towards other pets and/or people is probably trying to tell you something. Treating fear in cats The first thing to do when we see our cat displaying signs of excessive fear is to take them to the vet. ... (no cat flap here) & then suddenly refused to go out at all. However your mention of your cat jumping out of a window 20 feet from the ground is very worrying! He has no energy and not eating as well.