Who is the central protagonist of the long-running comic strip in which Snoopy remarks he is an "only dog"?
Snoopy's siblings: In Charles M. Schulz's comic strip "Peanuts", Snoopy was often stated to have seven siblings. Snoopy's siblings:  In the June 6, 1959 comic strip, following the birth of Charlie Brown's sister Sally, Snoopy remarks that he has no brothers or sisters, and is an "only dog." Charlie Brown: Charlie Brown is the central protagonist of the long-running comic strip "Peanuts", syndicated in daily and Sunday newspapers in numerous countries all over the world.
Charlie Brown