JRT/Rat terrier temperment

Question
I have a male JRT/Rat terrier that is 5 years old.  Recently, he has been "turning" on members of the family that he has previously been around and live with since he came to our home at 5 weeks old.  He is the only pet in the house.  I understand that terriers can be dominant.  He has never been "fixed" neither.  Why does it seem as if he has been changing, for the worse?  I wondered if he was "fixed" if that would calm some of the aggression down.  He won't let anybody else near me without him growling and barking, then eventually crying.  But about 2 months ago, my husband was holding him and he turned and bit his finger down to the bone and would not let go.  Just 2 days ago, "Taco" bit and scratched my 12 year old niece on the nose pretty badly.  She's on antibiotics and got a tet shot.  I'm lost in as far as what to do with him to help him.  Is this normal for this type of dog to do as it gets older?  He's so loving 99% of the time with me, except when he wants to do something and I won't let him.  He tends to growl and bark at me, but will make up immediately when I pick him up and love on him.  Nobody else in my family can do this.  I don't want to just ignore this as I'm afraid that it might get worse.  Any advice?

Answer
Tammy

This is NOT normal - and the first thing you should do is take him to the vet to rule out the medical conditions that can make this happen.

Once you know it's nor medical, you can address it behaviorally. YES - he should be fixed - even at this age - It will not cause him any harm and may help some with this problem. (notice I said "may")

You should also take him to obedience classes right away - and ideally with not just you as the handler.  Dogs can engage in all kinds of "resource guarding" and sometimes the resource is a person.  I do not mean for these classes to necessarily make him obedient, per se, but rather so you can learn to work together and so an outside person can assess the problem. PLEASE consider this - and make sure you get an experienced trainer, not just something at Petsmart (those are fine for simple problems).

The other thing you can do right now, is to read through this article and see how you can implement it in your household. You can;t let Taco get away with this, but you need to train him, not punish him....

http://cairnrescue.com/docs/NILIF.pdf

As a very good training friend of mine says "Dogs do what works"... so somehow this has come to get Taco something he wants.... so now you need to figure it out and try to teach him a better way....

Good luck.

-Beth