recently adopted Mastiff

Question
Hello,
I just adopted a 1 year old Mastiff a few days ago named Roxie and she's very sweet. However, she does seem very scared. She came from a breeder in which they intended to show her but she did not grow as big as they wanted (although I don't believe this because she is HUGE). I understand that a transition into a new home is very overwhelming for her and that she will be very skittish. However, she has become very protective of me and if anyone enters the house she stands in front of me and barks at them. I have to give the person a hug and tell Roxie it is ok. Eventually she will come around and let the person pet her. Today on a walk, a very large man approached her to pet her and she stood in front of me and barked and slightly growled at him, she seems to have a problem with men. I am just worried that she is getting too protective and that these might be signs of aggression. Do you think she is still trying to get used to her new surroundings or that these are signs of aggression? Thanks so much for your time and advice.

Lauren

Answer
This is the page that describes the Mastiff standard for size: http://www.akc.org/breeds/mastiff/ so you can check Roxy's height and weight against the standard. A Mastiff is a guardian breed, so the fact that she might be protective should not come as a surprise, and your breeder can give you some information on how protective Roxy's line tends to be.  Speak to your breeder also about Roxy's early socialization history.  Did this dog meet plenty of men?  Did she play off leash with other puppies at an early age (8-16 weeks)?  Regardless, I would not handle things as you have been. Rather, instead of hugging the person and talking to Roxy, let the person toss a treat onto the floor for her BEFORE she growls or barks.  You should probably invite the guest in, and have them be seated before releasing Roxy in to the room.  This page lists some of the characteristics of the breed, both good and bad: http://www.yourpurebredpuppy.com/reviews/mastiffs.html  Without seeing your dog, I cannot make an intelligent guess about whether she is fearful or aggressive, but the two are often closely linked.  You should be signing up for classes with her anyway, as large dogs such as this need to be under your verbal control.  Try to find someone who has a positive training philosophy but who has experience working with the guardian breeds.