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Kitty Korner with Big & Little: Feline Non-Recognition Aggression

Kitty Korner with Big & Little: Feline Non-Recognition Aggression

Kitty Korner with Big & Little

Big & LittleBy Mr. Big and Miss Little 

Big: Little and I are littermates; we’ve been inseparable our entire lives. We grew up together, had lots of adventures, had sibling rivalries, but mostly we’ve spent lots of time snuggling. A couple of years ago, I had to have three teeth extracted. Yuck; I only go to the vet once a year for my annual check up and this meant I had to go back a second time. The appointment went fine and I was really looking forward to going home to snuggle with my sister and recover. I had no idea that those plans were not going to go so smoothly.

When I got home I was still tired from the drugs in my system. So I was slow to get out of the cat carrier but I was excited to see Little walking toward me. Snuggle time! Except instead of rubbing noses with me and finding a sunny spot to curl up together in, Little reared back, hissed at me and took a swat at my nose! I was very confused but I was too tired to figure out what was going on so I snuggled with my mom so I could get some sleep.

Little: Big and I hang out together all the time. In fact, we even go to the vet together for our checkups so I was confused when Big left the house one day with mom and dad without me. Then later that day, they came back with the carrier they took Big in that morning, put it on the kitchen floor and opened it. And out came a strange cat that I didn’t know! My sense of smell is the first way that I recognize Big (not sight) and this cat didn’t smell anything like Big. Who was this intruder in my house? I had to act fast to show this strange cat who was in charge! So I hissed and swatted at it and ran off to find a safe place to settle down. My dad came over and tried to soothe me but I was sure something was wrong.

Beth and Dave:There was, in fact, something wrong and it’s known as feline non-recognition aggression. The aggression happens when companion cats are separated from each other for a period of time and one does not recognize the other when they are brought back together. Cats know the smell of their companions and that sense of smell is the first way they recognize each other. But following his dental surgery, Big did not smell the same for a variety of reasons. He smelled like other animals from the vet hospital and medical supplies, like alcohol and disinfectant. (The smell was not something we could detect but Little could clearly tell the difference.) And since he was still lethargic from the anesthesia he was not acting like his normal, playful self. Little took these differences as signs that the cat in front of her was not her brother.

We were not familiar with non-recognition aggression and didn’t immediately know what to do to fix the situation. We got Big and Little as kittens and they had always been together so we weren’t familiar with the steps to take to “introduce” them to each other. For a few days we let them try to work it out. Interestingly, we could tell that Little was confused; she would look at Big and he looked familiar but the smells were telling her something different. And poor Big had no idea what was going on but he was endlessly patient with her. We kept them apart as best as possible and did some research.

Once we read about non-recognition aggression we tried to find everything we could that smelled like Big to rub on him so he would get his “normal” scent back. We used the cushion from the carrier we took him to the vet in and rubbed it all over him. After we did it the first time Little did not react so violently to him so we rubbed him down again. Finally, Little could be around Big without going after him. We weren’t sure at that point if they would ever get back to the snuggly twosome they had been but we were making progress. After almost two weeks of a strained relationship we saw their first snuggle and knew we were back to normal. 


This was thier first snuggle after Big's dental surgery. 

Here are our recommendations if you need to take one of your cats to the vet or otherwise separate them for an extended period of time.

  1. Make sure you have lots of items that have cat smells on them. When the cat returns home, rub him with something that will help him get back the familiar scent.

  2. Don’t try to reintroduce the cats right away. Give them both time to de-stress and get back to themselves.

  3. Plan a controlled reintroduction so the cats can get to know each other again.

  4. And most of all, be patient. It can take as long as several weeks to get the household back to normal.

Big and Little: Yes, back to normal. Lots of adventures and lots of snuggles!