New male cat is aggressive with female cat

Question
Hi Katherine,
I have 3 cats.  Two are 6 year old males and one is a 3 year old female.  I just took in a friends cat who is a 2 year old male, because his newborn is allergic to him.  He is such a precious cat, and I have come to fall in love with him.  However, he has been aggressive with my 3 year old female since I got him on April 19, 2008.  I thought things would get better over time, but they have gotten worse.  I really want to keep him, but I can't let him go on chasing her.  She cannot walk by him or be in the same room with him, because he hunts her down and it ends in hissing, biting and crying.  It breaks my heart because I love them both and just want them to get along.  What do I do?  He is neutered already.  Please help...thank you for your time!

Answer
Hi Stephanie,

Thank you for your question.  You mentioned that the new male is neutered, but is your female spayed?  Even with a neutered male cat, if a female is not spayed he can sense that and this could be causing his reaction to her.

Also, when he first joined the household?  Did you introduce them slowly or just throw them all together?  With cats, you need to give them time to get used to each other slowly.  So, it is possible that you may need to separate them and reintroduce them slowly.  This can be done by keeping them in separate rooms and only allowing them together for a short period of time at first and slowly increasing the amount of time they are near each other until they are all together all the time again.  This gives them a chance to get to know one another while still being able to "get away" from one another at first.

Another thing you can try is a feline pheromone diffuser (feliway).  This can be purchased at most vets or pet stores.  Feliway is a safe solution of feline facial pheromone, which mimics the cat's natural pheromones, creating a state of well-being and calm.  This solution can help correct a number of unwanted behaviours in cats that are caused by anxiety or stress.

I hope this helps a bit!

Katherine