The behavior of our 1 year old Labrador retriever

Question
In the past couple of months she greets us wagging her tail in the friendliest manner while bearing her teeth in the most fearsome way. If with the mailman or fedexman she barks furiosly while running from one place to the other. What is going on?
Thank you so much. We are most concerned because of our small grandkids

Answer
A wagging tail only shows excitement.  She is a big girl and now taking charge.  If not spayed, do so now.  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 http://www.dogsbestfriend.com/  For more on being top dog, see http://www.dogbreedinfo.com./topdogrules.htm  There4 is also a page specific to children.

If any of the grandchildren are old enough, letting one of them take the dog to 4-H would be a great idea.  In my area, clubs form soon after the first of the year.  Even many urban
areas have 4-H.  For info look in your phone book under government listings
for extension or cooperative extension offices.  Ask specifically about a dog
or canine club.  Great grandparent/grandchild activity.