Winnie met 3 members of the family today (niece, nephew and sister in law) and for some reason she would not stop barking and growling at my nephew and was scared to approach him. She was fine with my niece and sister in law, tail wagging and acting like an excited puppy. But with him she was acting timid, tail down, barking and growling in a low gruff. She has never behaved like this with anyone before and has never barked at strangers in the street male or female, young or old. What could have caused her to behave like this? How do I train her out of it? I don't want to this be a problem any time he is around.