Male Chi Nutered - Mating with Female

Question
I have a male Chi that I had altered when he was about a year old.  I have a female Chi that has come in heat and the altered male chi and the female chi tied together. I know they did this for a fact, because I caught him humping her and was going to scold him and they were tied and I had to wait until they got apart before I could put him up.

I didn't think when they were altered this could happen. Is this normal behavior? I have another male chi that has been altered and he has never acted like this.  

My frisky male chi that tied with the female will often hump toys and I think this behavior may be normal.

I am just curious about this.

Thanks, Shirley

Answer
The behavior is a learned behavior, and some neutered dogs will still hump whatever is in site.  Although neutering removes the majority of testosterone, they still have a few hormones left.  When they start to do it, it feels good to them and continue the behavior just like a person would continue an addictive behavior.  Many times Chihuahuas will repetitively hump a big stuffed toy or someone's leg!  

Having the female spayed will greatly help reduce his urges as well.

I would try to discourage the behavior by redirecting him to something more appropriate like a chew toy, Kong filled with peanut butter or cream cheese or throwing ball for him to chase.  When he goes to jump on the female, squirt him with a bottle of lemon water.  If that doesn't work, simply pick him up and isolate him in a room with no attention OR keep the female crated.