It's not just New York rats that keep to their uptown and downtown stomping grounds, the Washington Post reports. Researchers have now also examined the genetic makeup of rats in New Orleans, Vancouver, and Salvador in Brazil to find clusters of rats in those cities as well.
Researchers led by Fordham University's Jason Munshi-South collected 150 rats from different parts of each of those cities and New York for analysis. As they report today in the Proceedings of the Royal Society B, they found closely related rats tend to stay together. Rats found within 500 meters of each other were the most closely related, with relatedness dropping off with more added distance. This, the University of Toronto's Marc Johnson, who was not involved in the study, tells the Post, could have implications for pest control.
In addition, Munshi-South and his colleagues uncovered geographical barriers that appear to prevent the spread of rats between different neighborhoods. For instance, they found that rats living in the French Quarter of New Orleans were genetically distinct from those living in the Lower Ninth Ward, with a canal separating the two populations, the Post notes. Roads, the researchers also found, separate rat clusters in Vancouver and Salvador.