I have 2 cats (female, neutered, 6 years old) and a 11 year old male dog also neutered. The three have lived peacefully since the cats were kittens. Recently the cats have started to intimidate dog. He is reluctant to walk by cats. I can hear him barking like he is scared or hurt but when I get to him I have no idea what went on. What is going on? How can I stop it?
There may have been an instance where the dog (innocently) did something that made the cats feel threatened and now they feel they have to protect themselves. It is very likely you weren't around when this happened so you don't know for sure.
I would seperate them for now. When you are home and can spend time with them, I would sit quiet in a room with all of them at the same time and step in and curb any aggressive behavior. Always do it quietly and gently, make all the animals feel safe. Over time the animals will feel comfortable again in each others company.
The only caveat is the longer you wait the less likely they will rebuild their friendship, so do it now and stick with it.
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