A cockroach on the Upper West Side is genetically different from one on the Upper East Side, according to researchers studying the pests.
Mark Stoeckle, a research associate at Rockefeller University, is working on the National Cockroach Project, a genetic study.
Researchers solicited dead cockroaches by mail from all over the U.S., and have gathered and examined about 125 specimens, mostly from New York, according to The Wall Street Journal.
The National Cockroach project hasn't found physical or behavioral differences between cockroaches in various parts of the city, but has learned other information about them.
According to the Journal, there are about 4,600 known species of cockroaches.
The smaller German cockroach is believed to have come to the U.S. with European immigrants, while the larger American roach is thought to have come from Africa aboard slave ships.
Stoeckle has learned that cockroaches behave much like humans -- in New York City, they stay in the neighborhoods where they grew up, and segregate themselves.
"Once they move in, they don't leave," Stoeckle told the Journal. "This is a window into cockroach society and it is very much like our own."