Ok so I've made a few posts about my cats recently but I'm just worried. My resident cat Noelle is 1 year. And the new cat is 10 years old. It's been little over a week since adopting Marley the 10 year old. We kept Marley isolated or rather tried to but she kept escaping when we went in to visit. One day she ran out and Noelle was right there and everything was fine maybe a hiss but other that nothing. Noelle is very curious about Marley and follows her everywhere i dont think Noelle has shown any aggression towards Marley not even a hiss. However Marley keeps hissing if Noelle gets to close and sometimes even swatting. What can I do to warm Marley up to Noelle?