Is Trip neutered?

Question
I have 2 cats that are brothers from the same litter. I adopted them when they
were 3 months old.  The shelter's policy mandated that the cats kittens be
neutered before I could take them home.  When I first took them into my
care, I had picked them up from the vet that had neutered them.  They are
very much in love.  They lick each other all day and play all day, but recently,
as they are now about 1-1/2 years old, one of them is beginning to bite at
his brother, and straddle him, insinuating sex.  He has also been more
aggressive with me and has been biting more.  Why do you think that is? Is
there a chance that he was neutered so early in his life, that his testicles
weren't fully developed? Or they only got one of his testicles?

Answer
Gretchen and Laurence,

There could be a VERY SLIGHT chance that he was not neutered correctly, but that usually doesn't happen. I would give the vet where you picked him up a call and voice your concerns.

There are quite a few neutered cats (usually starting about 3 years old) that start showing tomcat behavior. Some cats have a strong 'male mentality' and though they physically can't do anything they mentally can. Usually the cause for this behavior is that the neutered cat smells a female in heat somewhere in the neighborhood (even if they are inside cats) and is reacting to it. I have been told about neutered males that will hump other cats in the family (as yours is doing), male or female, dogs, peoples legs, and stuffed animals.

When he does that don't get mad at him or scold him because it's nature and he doesn't understand what he is doing wrong. But also don't pet him because that can get him more stimulated. Try to distract him with food or toys. He should quit doing it after a while.

Tabbi