apparently fearful-aggressive rat terrier

Question
I am asking this question for my aunt, whom I am trying to help with her recently-adopted rat terrier. I have owned several dogs over the last 30-some-odd years (one was a terrier mix), but have never encountered this exact problem. The terrier is an approximately 10-year-old female, picked up by the local shelter as a stray. She was already spayed, and in good physical health. No one knows what her past life was like. She seems to be quite nervous of people, except for my aunt, whom she has latched onto as if to a lifeline. She apparently gets on all right with my uncle, but does not encounter many other people, as they get few visitors outside of the family. The dog cringes and urinates submissively when I go to put her leash on for her walks (my aunt is unable to walk her). While on the leash she walks fairly well. The big thing is when she is on "mom's" lap, which is nearly every minute she is inside. She bared her teeth and growled at me when I went over to my aunt and reached out to touch her (the dog). I did not react, but touched her anyway, matter-of-factly, as I had been asked to check her rear end, which she had been chewing on. She did not try to bite, but stayed very tense. She does the same to the family cat (who was there before her), although she is gradually coming to accept him, after my aunt fussed at her for actually nipping the cat. She dislikes people leaning over her (which you can't help doing when you pet her, as she is so low to the ground). Today I walked her with my own dog (a very calm and good-natured Golden), and she did well and seemed to enjoy it, but when we got in the house she ran to "mom's" lap, jumped up and turned around and barked at both of us. I am at a loss as to the way to proceed with this dog. On the one hand she seems fearful and nervous, and on the other aggressive, at times, mostly when she is near "mom." I think she should not spend so much time on my aunt's lap, but have not actually suggested as much. (My aunt's previous dog was a mellow little chihuahua, who also lived on her mom's lap, so my aunt sees nothing wrong with it.) If you have any suggestions, I would be very glad to hear them.

Thank you very much,
Mary

Answer
Well, Mary, your Aunt and you have certainly found yourself a nervous little girlie, huh ?

Rat terriers are typically more high strung than most of the other terrier breeds, so your description does not surprise me.

She is doing what is called "resource guarding" with your Aunt being the resource. Think of her growling to keep you away from a bone, with your Aunt taking the place of the bone.

My strongest recommendation would be that you read through the article at this link and think about how to modify it for your situation.  You will need to strike a balance between making her act respectfully without breaking her spirit.  The thing that most people don't know is that dogs respond very well to structure and routine in their lives, so I think that building that for this dog would be great for the both of them.

In the meantime, I also recommend putting a harness on her. That makes a great handle if she needs to be gotten ahold of. I also sometimes have the dog drag a leash if there is any chance they are likely to bite. That way, they can be guided in the way you want them, but no one has to get really close to get ahold of her.

I really think she will respond well with some time and consistency.

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

Good luck and let me know how you make out.

-Beth