My cat suddenly attacked her housemates. How do I stop the aggression?

Thanks for using Petco Pet Education Center, formerly Petcoach! This is possibly because she smells differently. I recommend a product called Feliway which can help decrease stress and anxiety associated with environmental changes and stressors. You may find this online or at your local pet store. It usually works great in this type of scenarios. Good luck and have a great day!

A sudden behavioral change in cats that previously got along with no other changes to the environment can sometimes indicate issues such as underlying pain or illness. Bringing the cats in for an exam is a good first step to rule out any health issues that could be causing the aggression. If they check out healthy, adding in some pheromone diffusers can help with inter-cat stress. Making sure each cat has their own access to food, water, litter, places to hide, etc can also help decrease tensions.

Cats can often exhibit misdirected aggression. It is very difficult to know what may have caused it. I recommend using feliway diffusers and spray around the house to try to help calm them. Using Feliway wipes directly on each cat immediately prior to reintroducing them may help. Feliway is a pheromone product that can help woh anxiety and aggression in cats. https://www.feliway.com/us/

It may be due to illness or injury. It can also be redirected (or displaced) aggression. This is when one cat is unable to directly respond to a perceived threat and "vents" on whoever is closest. This is usually an owner or another pet. Never handle or grab your cat if she is displaying aggressive tendencies. This can lead to a serious bite or scratch. Schedule an exam with your vet to rule out medical causes. If they are indoor cats, provide a ' cool down' period by separating them. Keep stray or strange cats away from windows or doors and out of your yard. Control what your cat sees by closing doors or drawing the blinds. Consider using pheromone products to decrease anxiety/stress level in the house. Search www.pet360.com for pheromone products.

I hate to hear that. This situation can very very stressful and it's hard to know why this is happening. It's possible Kyo is sick and his odor has changed. It may be worthwhile to have him examined by the veterinarian to make sure everything is ok. It's also possible the cats are seeing or smelling another cats outside and this is causing stress and bullying behavior. Wipe down doorways and windows to eliminate odors. Here are a couple articles to help with cat aggression and stress: https://www.petcoach.co/article/5-tips-to-handle-an-aggressive-cat/ https://www.petcoach.co/article/causes-of-stress-in-cats/ You can help relieve stress by setting aside 30 minutes a day for vigorous play for each aggressive cat, provide climbing opportunities with cat shelves and cats treats, use a pheromone diffuser and provide separate litterbox and feeding stations. Lastly, your veterinarian can provide medications or a special diet called Calm which may help the cats. Best of luck and please feel free to post any additional questions.

A sudden behavioral change could indicate an issue such as pain or underlying illness, so if this happened suddenly or recently, having both cats examined for any signs of ongoing pain or illness is a good first step. if they check out healthy (aside for any known previous conditions), then adding in something such as a pheromone diffuser can help with stress between cats and aggressive behavior. Making sure both cats have access to their own food, water, litter, bedding, etc can also help decrease tension and stress over these items. If one of your cats is going blind or hard of hearing, adding in nightlights and making sure your cat can get around easily may help reduce stress related to these conditions and reduce tension between both cats.

Sudden behavioral changes are always concerning, and checking first for an underlying health issue is best. Cats can suddenly become aggressive if they're feeling unwell or are experiencing pain. If both cats check out healthy, looking for any changes that may be stressing them out such as new objects, new pets, new people, etc may help narrow down the causes of aggression. Making sure that both cats have access to their own food, water, litter, bedding, perches, etc can also help. A pheromone diffuser can also be placed in common/shared rooms to help decrease tensions and inter cat aggression.