He smells different so she is treating him as a stranger. You just need to go through the same steps as if you were introducing a new cat. Keep them separated, swap them into each others area and let them sniff around, do supervised introductions, try rubbing each cat with a towell and then rubbing the other cat to exchange their scents. At some point your female cat will realise if is her old buddy and they should be fine again but it may take a while. Also make sure she gets plenty of attention as cats are very territorial and young to make sure she knows you still love her and are not replacing her.

Sassy (2001-2012) answered on 10/9/11. Helpful? / 1

she though she was gonnta Rule the house alone then he came back she's angery at him

Member 1063218 answered on 10/13/11. Helpful? / 0