Brief explanation for those that didn't read my intro thread -
We have a three-year-old female, have had her for about seven months. We recently began the introduction of two males, aged two and one and both neutered.
We let the males out of the safety room and they've basically claimed the upstairs as their safety zone, venturing downstairs now and again.
To to point - The one year old ventured downstairs today and we witnessed the female headbutt him. I've read that headbutting is done from cat to human to either claim someone or show affection. My question is, would this behavior differ from cat to cat instead of human?