4 month puppy

Question
Hi I have a chihuahua x Pomeranian puppy and he is absolutely sweet. But a few nights ago my bf (who lives with me) walked in to the room and my puppy went insane! He was ferociously barking and growling and my bf tried to go near him to touch him and the puppy raised his fur and was showing his teeth yet  hiding down on the ground not being dominate in the growls. What do you think is wrong with him? He wasn't eating and my bf wasn't doing anything out of the ordinary! :(

Answer
The behavior sounds like what is called fear biting.  This is where a dog if fearful of strangers and bites before the threatening person has a chance to do anything.  I can't understand a dog behaving that way toward somebody that lives with it.  I am not sure what to say.  Keep an eye on things and post back.

It really isn't the answer, but things may be better if you are clearly in charge.  Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog.  Life is much easier if the 2 legged pack members outrank the 4 legged ones.  You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at http://www.dogsbestfriend.com/