i have 2 cats both neutered males they are brother from the same litter. my mother owned nitwit and he lived with her while his brother bug lived with me until september when i moved in with my parents. the cats had the normal initial issues with each other but they worked it all out. yesterday nitwit started being very aggressive towards bug for no reason. bug has not visited the vet recently or been anywhere that he would smell differently. nitwit makes horrible growling noises like ive never heard before and attacks bug who does try and fight back.....who can blame him? nitwit is declawed bug is not. nitwit is a very outgoing cat while bug is very shy and timid.....but neither cat is aggressive towards people at any time. they are both normally very loving. they are approximately 2.5 years old. can someone please tell me why nitwit has suddenly turned so hostile towards bug????? could it just be spring fever or something else??