Friend or Foe?
I have a neutered male cat, 7 months old. A week and a half ago I got a 5-month-old neutered male cat. Due to an upper respiratory infection/tapeworms/fleas, I had to isolate the new cat and he is still in isolation.
My current cat is at the bedroom door, trilling and rubbing his body agents on the floor and door that leads to the new cat's room. Ever since he saw the new cat, he always runs and head butts the door when he hears the new cat meowing.
Is this aggression or curiosity?