Why is my female cat suddenly aggressive towards my male cat?

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.

Have him examined by your veterinarian to diagnose illness or injury. Either are common culprits of a sudden behavioral change. Being an intact male may also be playing a role in the behavior. Consider having him neutered. In the meantime, provide additional food/water bowls, beds, toys and litterboxes to prevent food aggression or resource protection. Consider a pheromone product, such as Feliway Spray or plug in diffusers, to decrease any anxiety or aggression in the home.

Aggression can often be a response to pain. I recommend getting her checked by your vet as soon as possible, especially since she just finished a heat cycle. She could have an infection that is making her uncomfortable and in turn making her lash out against the kitten. You vet may run some labwork, do a physical exam, and based on these results, will be better able to tell you what is going on with your cat and how to treat her from there.

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.

Those are tough questions to answer without being there to visualize each cat. But I would say generally speaking whichever cat is acting abnormal. Abnormal behavior can mean anything from the cat being lethargic (lacking energy), vocalizing more, drinking more water, or even going to the litter box more frequently. As far as what illness could be causing this, there isn't enough information as of yet as to what symptoms either cat is displaying besides be increased aggression. Do some monitoring of both cats over the next few days to gather clues and then feel free to repost your question with specifics so that we can discuss some possible causes. However, in general we do worry about kidney and urinary infections in cats. Also a change in mood could indicate an endocrine disorder, brain malfunction or even diabetes. I hope this helps and look forward to more information about your fur babies. I do hope we can figure things out soon and get them to being friends again.

The vet could do a physical exam, blood work, and a urinalysis. It is a good recommended to take Banny into your vet for a health check when they are suddenly acting differently. It's the best way to know for sure that there isn't an underlying health problem, and behavior changes are often the first sign of a health problem in cats. When they are in pain or feeling sick, they can act aggressively. I do recommend the vet visit. Best of luck.

Stress and illness can be two factors in sudden behavior changes in cats, so getting Kosinus checked out by your vet is a good first step. Cats that are in pain or sick may suddenly lash out at friends or other pets when they were normally friends. If Kosinus checks out healthy, then looking for stress factors is the next step. Do the two cats have to share one food or water bowl? One litter box? One bed or perch? These can be things that may become contested, and if one cat is pushing the other out may lead to aggressive behavior. Making sure there are multiple litter boxes, beds, and food and water dishes may help. Pheromone diffusers that can be plugged into walls of shared rooms or used as a collar can also be useful for decreasing stress and aggression among cats, and may help Kosinus calm down some and get along again.