Redirected aggression happens when a cat becomes highly aroused by something they cannot reach, often another animal seen through a window, and then turns that aroused energy toward whoever or whatever is nearby instead, sometimes another cat in the home, sometimes a person. It can look sudden and out of character, but it is a response to the original trigger, not a change in how the cat feels about the target of the redirected behaviour.
Redirected aggression is one of the more confusing and alarming behaviours Cat Parents encounter, particularly in multi-cat homes, because it can seem to appear from nowhere between two cats who otherwise get along well. Understanding the mechanism behind it changes how to respond, both in the moment and afterward.
Cats who normally coexist comfortably can still experience redirected aggression triggered by something entirely outside the relationship between them.
What Redirected Aggression Looks Like
Redirected aggression occurs when a cat reaches a high state of arousal from a stimulus they cannot directly engage with, commonly an outdoor cat or animal seen through a window, an unfamiliar sound, or another perceived threat just out of reach. Unable to act on the actual trigger, the aroused cat turns that intensity toward the nearest available target instead, which might be another cat sharing the home, or a person who happens to walk by or attempts to intervene. The behaviour can include hissing, swatting, or biting, and it often appears abrupt because the original trigger may not have been visible to the Cat Parent.
Common Triggers
An outdoor cat or animal seen through a window
This is among the most common triggers. An indoor cat who spots an unfamiliar cat in their outdoor territory, with no way to confront it, can reach a high state of arousal quickly.
An unfamiliar or startling sound
A loud, sudden noise, particularly one the cat cannot identify or locate, can trigger the same kind of aroused state that then gets redirected toward whoever is nearby.
A perceived territorial intrusion
Sounds or scents suggesting an unfamiliar animal near the home, even without a direct visual, can be enough to trigger the same underlying arousal response.
What to Do in the Moment
Do not attempt to physically separate or restrain a cat in an aroused, redirected state, since the same intensity directed at another animal can turn toward a hand that reaches in. Instead, remove the visual or auditory trigger if possible (close blinds, block the window view), and give the cat space and time to settle without direct physical contact.
If two cats are involved and the aroused cat has redirected toward the other cat in the home, separating them into different rooms, using a barrier rather than physical handling, allows both cats to de-escalate safely. Loud noises, sudden movement, or attempts to comfort a cat mid-episode can prolong the aroused state rather than shorten it.
After an Episode
Following a redirected aggression episode, cats involved, particularly two cats who redirected toward each other, may need a period of separation and a slow, gradual reintroduction rather than being placed back together immediately, since the arousal state can take time to fully settle and one or both cats may remain wary for a period afterward. Identifying and reducing the original trigger where possible, such as blocking a window view of outdoor cats, is the most direct way to reduce how often episodes occur.
An episode of redirected aggression between two cats who otherwise get along does not reflect a breakdown in their relationship. The behaviour originates from an external trigger, not from how the cats feel about each other. Most cats resume their normal relationship once both have had time to de-escalate, though a slow reintroduction is a reasonable precaution after a significant episode.
Frequently Asked Questions
This is often redirected aggression, where one cat becomes highly aroused by a trigger they cannot reach, such as an outdoor cat seen through a window, and turns that intensity toward the other cat in the home instead. It can look sudden because the original trigger may not have been visible to you.
Yes, giving both cats space to de-escalate using a barrier rather than physical handling is the safer approach. A gradual, slow reintroduction rather than immediately placing them back together allows the arousal state to fully settle for both cats.
No. A cat in a highly aroused, redirected state can turn that intensity toward a hand that reaches in, even if the person is not the target. Remove the trigger if possible and give the cat space and time rather than attempting physical contact.
This content is for informational purposes only and is not a substitute for professional veterinary or behavioural advice. If aggression between cats in your home is frequent, severe, or does not resolve with separation and time, consult your veterinarian or a qualified feline behaviourist.
