Reintroducing Cats That Have Been Separated

Sometimes even a short separation between two house cats requires a careful reconnection.


Your two cats are the best of friends — lounging together, looking out the window together, and generally content to share the house with each other. But then one of them goes to the veterinarian and is out of the house for an hour. Or the two of them need to be boarded for a couple of days. You’d think when things go back to normal, the cats would be relieved and happy. But often, the opposite happens. Fighting breaks out. It’s like the two feline pals never knew each other and are now enemies.

It’s a common problem, says the head of the Tufts Animal Behavior Clinic, Stephanie Borns-Weil, DVM. “People with more than one cat are at risk of experiencing this rift between their feline pets.”

What causes the behavior? “We don’t actually know,” Dr. Borns-Weil says. What we do know is house cats live in a circumscribed world where everything is always the same. They may not be flexible when it comes to change and then settling back in. “The situation has forever shifted even when you work to put things back together exactly as they were,” the doctor says.

This can be true even if two cats go to the vet at the same time — in the same carrier! They get home, and because their routine has been disturbed, they are no longer the same to each other. The stress of the experience causes one or both to start lashing out. It’s thought to be a form of redirected aggression (described in the October 2020 issue). The cats can’t do anything about what’s bothering them, so they take it out on each other.

How to remedy the rift

You cannot reason with a cat or expect him to just “snap out of it” when he goes off on his housemate. Instead, you have to keep the two cats apart for a while.

It may take keeping them in separate rooms, at first with the door closed and then opened just a bit. You may have to feed the cats separately at first, too. Gradually, you can engage them in positive activities together — chasing a feather on a stick, shining a beam on a wall. You may want to put a toy with the scent of one of the cats near the other, and vice versa.

It shouldn’t take long for the two pets to come back to themselves — maybe a couple of hours. But word to the wise: without a staged reintroduction, the fighting will continue. They need your intervention to get over the hump.


  1. Bwfore you separate cats wipe them down with a clean towel. If they are boarded or have been at the vets, use that same towel when they come home to over ride the vet smell or boarding smell.


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