LAS VEGAS, Nevada.  Capitalizing on the runaway popularity of the World Series of Poker, Harrah's Entertainment today expanded its franchise contest from men and women to man's best friend as the first World Series of Canine Poker opened with 120 dogs plunking down their "buy-in" stakes at the Lucky Dog Casino.

            "People think that dogs only play poker on cheap wall hangings you buy in strip mall parking lots, but we're for real," said Fritz, a Doberman pinscher who has traveled here from Flint, Michigan.  He motions to Fifi, a comely French poodle waitress who is raising her mutt son by herself.

            "What'll you have?" she asks Fritz, whose eyes drift southwards to her d