I have two cats that are brothers, Tai and TK, and they are 13 years old. They have always gotten along very well. They groom each other, play-wrestle, and have no problem sleeping in the same rooms and sharing space, litter-boxes, and food. The big one, Tai is about twice the size of his brother TK, and is usually dominant. He always ends up on top when they wrestle. Lately, Tai has been chasing TK around the house. It doesn't seen like friendly play. What could be causing this and what should I do?
