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Dena had a 2-year-old cat spayed. Now that cat is aggressive with the others in the household. Is it due to the spay, or to something else?

Cats can become aggressive after surgery, but it may not be due to hormones. Photo via Pixabay

Dear Most Esteemed and Knowledgeable Kitties:

I have recently rescued a 2-year-old queen who I’ve had spayed. Before her surgery she was fine with all the other cats. Since her operation, she has been pointedly aggressive towards one of my male (neutered) cats. Is this due to her change in hormones, and if it is, how long will it take for her to settle? I don’t want to rehome her, but her bullying my old boy is unacceptable. Please help.

~ Dena

Thomas: Well, Dena, there are a couple of reasons your cat might be aggressive after her spay. It will take a couple of weeks for her hormones to calm down, but cats don’t typically become aggressive just because of hormonal changes.

Bella: We suspect that what you’re dealing with is a case of redirected aggression.

Tara: That is, after your cat was spayed, she was probably in pain and feeling vulnerable. Something startled her, and she lashed out at the nearest object–which, in this case, is your old boy kitty.

Thomas: But before we get into the whole discussion of how to treat redirected aggression, we do recommend that you get in touch with your vet and ask about your cat’s behavior change. You want to rule out any lingering medical problems before you assume the issue is behavioral. You should also take the older cat to the vet and see if he has any medical problems like arthritis that might be causing him to feel less confident.

Bella: If she gets a clean bill of health, then you can start treating the redirected aggression issue.

Tara: The first thing you’ll want to do is get some feline pheromone plug-in diffusers. These are sold under the brand names of Feliway or Comfort Zone. You can find them in most pet stores or online. Use the diffuser in the room(s) where the cats hang out most.

Thomas: These diffusers release “happy cat” pheromones,” which can help calm down aggressive kitties and shore up the bravery of the victim cats.

Bella: After you get the diffusers, you’re going to want to use play as a tool to treat the redirected aggression.

Tara: Playing with your female cat will work out all her “killer” instincts on a toy. Playing with your older male “victim” cat will build his confidence.

Thomas: We recommend using “thing on a string” toys. Our favorites are Neko Flies and Da Bird, and you can get these at pet stores and online, too.

Bella: You’ll need to keep a toy with you at all times when you’re in the room with your cats. As soon as you see signs that the female cat is “hunting” the male cat, get the toy out and play with her. That way you’ll redirect the redirected aggression into a more appropriate outlet.

Tara: Run her around and get her tired. After she’s done playing, give her a little treat so she can feel like she’s “killed” her prey. Then she’ll probably groom herself, curl up and go to sleep.

Thomas: How do you know when your cat is becoming aggressive? Cats can be very subtle, so you’ll have to look for seemingly innocuous body language changes. Look for her ears moving forward and then flattening and turning sideways, and her eyes focusing on the victim cat. Staring is a sign of aggression in cats.

Bella: If she starts tensing her body as if she’s about to leap, that’s a sign that a chase is about to happen.

Tara: As soon as you see even a hint of oncoming aggression, get the toy out and play with her.

Thomas: When you play with your “victim” cat, you’ll want to do the same thing: get him moving and allow him to “kill” the toy multiple times. Then give him a treat and let him wind down.

Bella: You also want to make sure that there’s plenty of vertical territory. A lot of people don’t think about how important it is for kitties to be able to get high up on a cat tree or the top of cabinets, but it is super-important to have that vertical space.

Tara: First of all, it will add more “territory” to your home, which may help with disputes around who “owns” what part of your home. Cats think in three dimensions, so even if you have a tiny apartment, if you get some cat shelves or a cat tree, that will help everyone.

Thomas: If play, pheromone diffusers and increasing vertical territory don’t stop the redirected aggression, you may have to go through the process of reintroducing the cats.

Bella: Our cat behavior hero, Pam Johnson-Bennett, has a great guide on how to reintroduce cats whose relationship has been damaged by aggression. We highly recommend you read it over and see how you can make a reintroduction work in your home.

Thomas: By the way, if you want a great book that combines all of Pam’s advice in easily digestible snippets, we recommend her new book, CatWise.

Bella: What about you other readers? Do you have tips for Dena on how to manage her cats’ aggression? Have you had a situation like hers, and what did you do about it? Please share them in the comments!