Why does my cat attack my other cat for no reason?

When I started my career more than 20 years ago, consultations for cat aggression in the same family were rare. Today it has become the second reason for behavioral visits after impurity problems. Every week I see owners distraught over felines who seem to hate each other for no apparent reason. But be careful: there is always an explanation for these behaviors. Let’s decipher this phenomenon together and find appropriate solutions. 🐱

Quick summary:

Conflicts between domestic cats are becoming a common reason for behavioral veterinary consultation requiring appropriate interventions.

• Differentiate play from aggression : alternation of chases without vocalizations (game) with growls and injuries (aggression)
• THE common causes include medical problems, foreign odors after outside visits, and competition for resources
• In case of a dispute, intervene indirectly without punishing the attacker to avoid making the situation worse
• Sustainable solutions require the multiplication of resources and the enrichment of the environment in three dimensions

How to distinguish play from real cat aggression

The first question to ask yourself when faced with sometimes tumultuous interactions between your felines is: is it a game or a real aggression? Appearances can be deceiving, especially when you witness a high-energy chase sequence or rolling on the ground. I have often reassured worried owners when their pets were simply having fun.

Cat play is characterized by chases in which the roles are regularly reversed. You will notice that the claws remain retracted and the bites are controlled, without causing injury. The absence of aggressive vocalizations such as howling or spitting usually confirms that it is a game. If tufts of hair fly, don’t worry right away, this is often linked to the adrenaline rush which involuntarily makes the hair stand on end.

On the other hand, real aggression presents very different signs:

• Hissing, spitting and loud growling 😾
• Extended claws and uncontrolled bites
• Presence of injuries after interaction
• Escape of one of the cats, often chased by the attacker
• Tense and defensive body postures

One day, a client showed me a video of her two kittens chasing each other around the apartment. She was convinced they were arguing, but the pricked ears and the alternation of roles allowed me to reassure her: unlike the aggressive behavior we can observe in other pets, this was simply a normal game between young felines.

Why are my cats suddenly no longer getting along?

It is not uncommon for two cats who coexist peacefully to start fighting with each other for no apparent reason. This situation often baffles shipowners, but several factors can explain it.

Medical problems are a common and underappreciated cause of behavioral change. A sick cat becomes irritable and may refuse all contact, even with a normally liked companion. I recently diagnosed early arthritis in an 8-year-old feline who had started attacking his young companion: after treatment, their relationship normalized.

The return of one of the cats after a visit to the vet or groomer can trigger aggression. The foreign odors it brings disturb olfactory recognition, a fundamental element of feline interactions. A move also represents an important stress factor for these animals linked to their routine and their territory.

Competition for resources is another classic trigger. Here is a summary table of resources potentially a source of conflict:

Remember that cats are territorial by nature. Even after years of cohabitation, a stressful event can reactivate their territorial instinct and trigger exclusionary behaviors towards their peers. If your cat also has elimination problems, check out our guide to litter problems, as the two problems are often linked.

How to react effectively during a cat fight

When faced with a conflict between your felines, your reaction can calm or escalate the situation. During my years of practice, I have observed that owner panic often amplifies tensions between animals. Stay calm and follow these tips. 🧘‍♀️

First, identify the situations where intervention is necessary:

Small altercations to negotiate resource sharing are normal and generally do not require intervention, as long as they do not degenerate. Instead, intervene immediately if you notice attacks with extended claws, prolonged fighting or if one of the cats shows signs of intense fear (tremors, involuntary eliminating).

To separate two cats in the middle of a fight, don’t make the mistake of grabbing them directly with your hands: you risk seriously injuring yourself. Prefer indirect methods such as throwing a pillow near them (without aiming at them) or using a blanket as a barrier to guide one of the felines towards an isolation room.

Never punish the aggressive catbecause this would increase his stress and make the situation worse. I have seen cases where owner yelling and punishment turned occasional aggression into a chronic problem. After separation, isolate the less fearful cat in a quiet room with water, food and litter for a few hours.

Sustainable solutions for harmonious coexistence

Resolving cat conflicts requires patience and a methodical approach. Being a veterinarian, I always recommend a multi-step strategy to bring peace back to your home. 🏡

The first measure is that multiply and diversify the available resources. Provide different bowls, litter boxes, water points and rest areas in different rooms. This abundance reduces competition and allows each cat to access what it needs without confrontation.

Environmental enrichment plays an essential role. Organize your space in three dimensions with shelves, scratching posts and perches. Each high point should have two separate entrances to avoid trap situations. This vertical organization allows cats to avoid each other while still sharing the same space.

Relaxing feline pheromone diffusers can complement your device. I have found them effective in many cases, particularly when introducing a new cat. For more complex situations, homeopathic anti-stress treatments can be considered.

If one of your cats returns after a vet visit, isolate him for a few hours and then plan a reunion around a positive experience such as handing out tasty treats. This association creates positive conditioning that can gradually transform their relationship.

If despite these measures tensions persist, do not hesitate to seek advice. A thorough medical examination may reveal an underlying health problem, and a feline behavior specialist will provide you with a personalized plan tailored to your companions’ specific situation.