sudden wierd behaviour change

Question
Hello, hoping you can help.

We have two cats, 7 years old, brothers from the same litter.  The cats have never been separated and in fact are typically overly affectionate to eachother (and humans). Both are healthy.

Two nights ago, the one cat Mouzer showed an extreme personality change.  He was hissing, growling and picking a fight with his brother. Every once in awhile this cat does get into a bit of a grumpy mood, but never anything like this.  The fighting has continued over the past two days, but his aggression and hissing is primarily directed at his brother.  He has shown little behaviour change towards our dogs or us.  

The only "change" that occurred, was with the sudden temperature increase here, my husband spent a couple of hours brushing the cats and giving them a bath.

We'd appreciate any ideas/suggestions that you may have!

Thanks,

SerenaRae  

Answer
Hi, SerenaRae.  Sorry to hear about your problem.

What I would have to suggest is to have your kitty seen by a vet.  Illnesses ranging from urinary tract infections to gingivitis or a broken tooth can really cause a cat pain, and they can become very aggressive.  While this would generally result in aggression toward everyone, I would feel terrible if I didn't recommend a vet visit and he turned out to be painfully ill.

Usually, when a cat suddenly dislikes one particular person or pet, it's linked to some traumatic experience the cat had while in the presence of that person or pet. It's called redirected aggression.  It's possible it could have been the bath if your husband bathed them while they were in the same room.  However, more commonly, it's caused by a loud noise or by seeing something outside that scared them.  For instance, I've had cats redirect aggression to other pets when a plate fell and shattered.  There's also a neighborhood cat who comes and howls at my window, and this causes my cats to turn on eachother sometimes.  Vet visits are another common cause of redirected aggression.

If you can identify what may have happened and prevent it from happening again, that would be ideal.  If there's a cat outdoors that may scare them, some people use window shades that are set in a track that the cats can't get behind.  If you think the bath could be the culprit, bathe them at separate times when need be.

As for this episode, the best way to deal with it is to keep the cats completely separated for a few days.  Allow the memory of the conflict to fade.  Then try reintroducing them slowly, for short periods a few times a day until no problems are noted.

Another aid that may help is a product called Feliway.  It's a synthetic facial pheromone, which helps reduce stress and anxiety.  Its first purpose is to treat litter box problems and destructive scratching, but it also works wonders with many aggression problems.  It comes in a spray bottle that you can use to treat bedding and furniture, etc., and also in a plug-in diffuser called Comfort Zone.  I recommend the plug-in because it's easier to use and treats entire rooms.  It runs about $30 and is available at pet stores or through their site, www.felineway.com.

If you still continue to have problems, I would recommend to consult a Certified Applied Animal Behaviorist, or a Veterinary Animal Behaviorist to see if they have any insight as to the cause of the problem, as well as a solution.