The age-old question about whether or not there really is one rat per New Yorker arises in today's NY Times City Section. While the number of rats hasn't been officially counted, the Times answers:

As for “one rat per person,” that is a myth that has persisted for at least 100 years. As Robert Sullivan noted in his 2004 book, “Rats,” a naturalist named David E. Davis analyzed New York’s rat population in 1949 and called the one-rat-per-human statistic absurd. (The statistic had come from 19th-century England and was never more than a guess.)

Mr. Davis found, for instance, that there were probably no more than a few thousand rats in the entire waterfront. He put the rat population of New York at about 250,000.

And whatever the actual number, it fluctuates because of changes in seasons, weather and food supply.

Okay, but that's a statistic from 1949 - we're sure rats have adapted in the past fifty years. We would imagine the NYC rat population to be at least 1 million. Because when there's one rat, there's more.

And the Robert Sullivan book "Rats" is really good. Creepy, but good.

Photograph by Jason Toney