Bulldogs with Bulldogs

Question
I have a 4 1/2 month old english bulldog.  A friend of ours has one
of her sisters.  Both puppies are very friendly and play very nice
with all other dogs except for each other.  When they see eachother
they show their teeth and bite each other's lips and are much more
aggressive with each other then other dogs.  Is this strictly
aggressive behavior or do they feel they can be rougher with each
other?  I am not sure if this is because they are both bulldogs or if
it is because they are related.

-Kristin

Answer
This is instinctive pack behavior between siblings, but it is still unacceptable. These two both need obedience classes and now is the perfect time.  They have to learn that this behavior is not going to be tolerated. The more socialization you can give your dog, the more well adjusted he will be as an adult. Although this is fairly typical Bulldog behavior it is still not to be accepted.