The Bulldog is one of the favored animal mascots for many organizations, including the United States Marine Corps, Georgetown University (Jack the Bulldog), Yale University (Handsome Dan), and the University of Georgia (Uga the Bulldog).
There is probably a different reason each organization has chosen such a loving and intelligent creature, but the reputation these wonderful animals have as being ferocious and loyal probably plays an important role.
Over the years, the bulldog has been portrayed by the media as an "attack dog" and in some instance the whole breed has been condemned as a menace. In my personal experience, I have found that the exact opposite is true - it is just another case of prematurely "judging a book by its cover", and some of these dogs being in the wrong place at the wrong time.
Regardless of the reasons, Bulldog fame will continue in this country - and I think its a great thing.