yorkie aggression

Question
Dear Erica,

I have a 2 1/2 year old male yorkie. He is really sweet and playful. We also have a large mix breed and two chihuahuas. Recently my dog has begun nipping and bitting at people when they first walk in the house, as well as, if they walk in front of my house. The strange part is that rite after he nips at them with in five minuted he is fine. I am so upset over this because he really is a nice dog i am just wondering how to curb this agression.

Answer
This is a very normal behavior with Yorkies, as well as other headstrong breeds.  He is trying to establish himself as head dog to everyone that comes over.  Keep him on lead when you have visitors and work on a reliable sit/stay.  Reward for calm polite behavior and ignore the aggressive behavior while maintaining a safe distance-so he cannot bite your guests or neighbors, etc.