[kanis]

A very odd thing happened between my boys tonight. Another cat came into our backyard and came up to the screen door where my boys were. Our boys freaked out, scared the other kitty away and have been growling at each other ever since. Zeus has been particularly stand offish with hissing and growling. Ukko has made attempts to approach Zeus and Zeus just hisses and growls. Ukko is fine with me, cuddling and rubbing but Zeus is very freaked out. These two boys love each other and constantly cuddle and clean each other. It's strange to see Zeus so aggressive towards Ukko. I mean they have their moments but nothing like this.

Any suggestions as to what I can do? Did the other cat just scare Zeus so much that he's scared of his own brother now? Will this behaviour subside on its own or will an intervention of some sorts be necessary?