Radical Kitten Behavior After Being Spayed & Neutered

Question
I have two 4 month old kittens from the same litter, male and female who were best friends. Ever since, they were spayed and neutered yesterday they hiss and growl at each other constantly and can't stand to be close to each other. Why are they behaving that way?

Answer
Isaiah,

That is common, and perfectly normal behavior for cats coming home from being fixed, or going to the vet.

Cats go by smell and not by sight in recognizing other cats (with humans, they go by voice...not by sight). Your fixed cats brought home MANY different smells from the vet: anesthetic, medicinal smells, and smells of other cats...all clinging to their fur and skin so they think each other is another cat because they don't smell like they used to.

As the cats groom themselves they will be replacing their regular scent. You can keep them separated if you want until the smells are gone from their fur. It will take a few days.

A trick that I've heard a lot of people use in that situation (though I have never tried it) is to put a small drop of vanilla on each cat's forehead so they smell the same.

They also can be hissing and growling at each because they hurt from the surgery and are blaming each other for it.

They will be back to normal soon. And you are a responsible pet owner for getting them fixed!

Tabbi