We have a therapy dog in our nursing home that I work at. It's a Golden Retriever that lies around most of the time. There is one patient that the dog growls at. Any idea why the dog does this?

I have a question I was unable to find already answered in the FAQs. I work at a skilled nursing facility with approximately 50 residents. The facility has a beautiful (slightly overweight) golden retriever that is very calm, gentle and even tempered. She loves to be the object of your attention and returns affection appropriately and never becomes over excited. In a word, this dog is perfect.

The dog was lying in the sun rays on my office floor snoozing, when one particular resident walked by my door. The dog's response was surprising. She lifted her head, stiffened her entire body, bared all teeth and growled viciously. The resident walking by my door was looking straight ahead and didn't respond to the dog's behavior at all.

Upon investigation, I learned the dog ONLY growls at this particular person and has done so since the resident first stepped into the facility. AND does so for no particular reason. The resident likes dogs, isn't afraid of her, or dogs in particular, and has not been mean to our dog in any way, shape or form. The only thing I've come up with is kind of strange to even mention, but the resident the dog responds to in this particular fashion has a mental disorder and presents an extremely flat affect. I've understood for some time dogs (and other animals) can sense much more than humans.

So, the question is: Why do you suppose this mild-mannered dog responds this way to only ONE person out of at least 80-90 people she interacts with per day?