Why are my cats fighting all of a sudden?

Original Question: Good morning. Hoping you can offer some suggestions. So I have 2 female cats that are 11 years old and I have had them both since they were kittens. They’ve always gotten along for the most part, like they will both sleep on the bed with me at night and would play together now and then. I’ve seen the smaller cat torment the bigger one now and then over the years and she hisses when she doesn’t want to play. But that was all that I’d really ever seen in terms of aggression. We’ve lived in the same space for 9 years so the environment hasn’t changed and last week in the middle of the night they started fighting making these awful growling noises. And basically the past week they have been fighting repeatedly at night with these awful growling, whining noises. The other day I watched the bigger cat go to eat and the smaller one just walked over and hit her in the face with her paw it seemed out of nowhere. Not sure what to do because the fights seem to last a long period of time and the hissing and growling noises seem to be getting worse. It seems like 1 cat is instigating but I’m not entirely sure. Both cats are still being fine and affectionate with me just not with one another. Not sure what to do? - Mel

Apr 26, 2018

Hi Mel,

Behavior is always a challenging subject to deal with. When you have sibling cats suddenly fighting, I would first look at considering if they are resource guarding – they should have their own separate food bowls, a multitude of toys, and you should have at least 3 litterboxes in the house. Next, I would consider if there are stresses in the home or other changes – visitors, death or birth in the family, job changes that affect the schedule, use of air fresheners or plug-ins. It wouldn’t hurt to get a vet check up for both cats to make sure one or the other hasn’t developed a condition that the aggressor might be picking up on or experiencing.