New York's Rat Population Smaller Than Believed, Researcher Says

The claim that New York City is home to 8 million rats — or one for every human resident — is probably a tall tale, according to research by a Columbia University statistician, Reuters reports.

In truth, the city's rat population is probably closer to 2 million, said Jonathan Auerbach, a Columbia doctoral student who wrote an essay on the subject published in Significance magazine.

According to MSN.com, the "one rat per person" claim stems from a study of rats conducted in England by W.R. Boelter and published in 1909 under the title The Rat Problem. Boelter surveyed the English countryside (but not villages, towns, or cities) and came up with an educated guess, estimating that England had one rat per acre of cultivated land. Since England had 40 million acres of cultivated land at the time, Boelter pegged the country's rat population at 40 million. And since England also had a human population of 40 million at the time, there was some basis for claiming that the country was host to one rat per person.

Auerbach's research drives another nail into this myth's coffin. He estimated the ratty multitide using a thoroughly modern method — delving into open data, in this case the Department of Health's trove of 311 calls for rodent sightings. Auerbach counted the distribution of rat alerts among New York's roughly 842,000 property lots, and then ran a statistical analysis to extrapolate population numbers. His conclusion: The rat threat has been greatly exaggerated, as there are probably only about 2 million whiskered critters in the city.

Sources: MSN.com and Reuters