aggression in my chihuahua

Question
I have had my 2 year old male chihuahua since he was 6 weeks old, and he is very attached to me. however, when I leave for work, he jumps onto the back of the couch, growls, barks, and tries to bite me. also when we're sleeping, he has shared the same bed with us for 2 years and recently started biting us if he is touched while sleeping. he is in good health with no medical problems and is not nutered. please help.  

Answer
Hi DeAnna...

Well, the first thing that stands out to me is that your dog is not neutered.  Anytime you experience aggression and territorial behavior and a dog is not neutered, it's quite apparent that this is something that needs to be done - meaning neutering him.  

Insofar as the standing on the back of the couch, growling and trying to bite you as you leave goes, I find that to be odd behavior that warrants further medical evaluation/testing if he continues to do this after having been neutered.  You say that he's in good health, but I'm wondering if you have had a full blood panel run AND a thyroid test done? Dogs have been known to have hypothyroidism when as young as 2 years old and dogs with hypothyroidism are known to display aggression.  I have a Chihuahua here that was diagnosed with hypothyroidism last year and he was displaying some aggression.  Since he has been taking a hormone for the condition, he's almost like a different dog.  I want to note here that he is also neutered.

One of my Chihuahuas (who also sleeps with us) is very grouchy if you touch him while he's sleeping.  He was a little rescue dog and tends to be on the nervous side and defensive at times.  He has never tried to bite us though.  Again, I attribute the excessive reactions your dog is having to not being neutered.

I advise people to adopt pups as near to 12 weeks old as possible because they are better adjusted and have learned lots of limitations in behavior from their mother and siblings which means far fewer behavior problems.  We often see obvious behavior problems in dogs that were taken from their mother and siblings too young and you especially see this with so many dogs dumped at shelters.  They just don't have an idea of what their boundaries should be so much of the time.  Add to that that they are not neutered and you have a dog that has raging hormones which are dictating behavior that they didn't learn was inappropriate when a young pup.

I hope that the information that I have provided here is helpful to you and that you will strongly consider getting your little guy neutered as soon as possible.  I also suggest that you do NOT use a low cost neutering facility for this.  A neuter is a pretty simple procedure but you want to make sure that the doctor has lots of experience with small breed dogs and that he is using the safest anesthesia possible.  Feel free to write me back if you would like to discuss safe neutering protocols.

Jo Ann