Are vampires good at mathematics? Perhaps those who were once accountants and bankers. Perhaps those who failed algebra courses not so much. In fairness, even for vampires who own calculators, it might be hard to keep track of how many victims they have bled over the decades, over the centuries.

In some folkloric traditions, vampires who encounter spilled grain or seeds must count them, apparently due to a type of supernatural arithmomania. Woe to the less-educated vampire who could not count as high as the number of seeds on the ground. Or to the vampire who kept losing count and had to start anew repeatedly until it dawned on him or her that it was dawn. Perhaps there are times when it's preferable to be the Count von Count of Sesame Street.

Such mathematics may or may not be important, but to the vampire hunter, the vampire enthusiast, and the vampire scholar, one number is as dramatic as it is baffling: the global vampire population. According to much folklore and literature, vampires give rise to more vampires. Biting one creates another, the process repeats, and then repeats, and so it goes. In Bram Stoker's Dracula, Van Helsing refers to the title character as the “King Vampire.” At the end of the nineteenth century, there were fewer than two billion people in the world. But how many supernatural vampires were there, if not in the real world, then in the world of fiction? Over how many undead did Dracula reign?

Put another way, the problem is that, by a given point in time, every person would either die or transform into a vampire. As more vampires are spawned, more blood is necessary, and so the scarcer it gets. Eventually there would probably be, as the title of Ubaldo Ragona and Sidney Salkow's 1964 film warned us, The Last Man on Earth. Then he too would become either dead or undead. Thus, earth could accurately be called, to borrow the title of Mario Bava's 1965 film, Planet of the Vampires.