I have a 5 month old Dobberman/German Sheperd mix. He's a great dog and is very protective of me and my girlfriend. He's been acting a little bit strange and I didnt know if it is typical behavior for his breed. A couple of days ago my girlfriends mom( who is really gentle towards him) was walking toward him and he started growling and the hair on his back stood up along his spine. I reassured him that it was ok and began to pet him till he stopped. Yesterday my girlfriend was walking towards our house and again he started growling and the hair on his back stood up. She had to reassure him that it was ok and pet him. Is this Normal?...and any reason as to why he might be doing this? Thank you!
Jasmin

[Yogi]

The other issue here is that this dog is bonding with you to the point that it is starting to be overly protective. Though not a bad thing per se, it does require attention to avoid out of control defensive issues becoming ones of aggressive issues.