How do I teach my almost 5 month old jack russell cross chihuaha puppy, that my son is the boss and to respect him more?

She knows I'm boss, but she bites my son whenever she wants, he's 4yrs old.

The key to most behavior problems is approaching things using the dog's natural instincts. 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 Raising Your Dog with the Monks of New Skete (http://www.dogsbestfriend.com/) For more on being top dog, see Establishing and Keeping Alpha Position, Letting your dog know you are the boss (http://www.dogbreedinfo.com./topdogrules.htm) Follow their link to the page on children.

If the dog ever tries to do something demanding or controlling your son should show that he is on top by demanding back. But make sure that he shows the dog he's not afraid... and use a strong voice, when the dog sees that you have power over him he'll back down and respect you...

Is your dog doing this aggressively or while trying to play?

I've noticed that dogs and other animals seem to behave and look at human children differently than the adults. I think that they are aware that it's the baby of our species and not just another people.