Rats in New York City
Rats in New York City are prevalent, as in many densely populated areas. For a long time, the exact number of rats in New York City was unknown, and a common urban legend was that there were up to four times as many rats as people. In 2014, however, scientists more accurately measured the entire city's population to be approximately only 25% of the number of humans; i.e., there were approximately 2 million rats to New York's 8.4 million people at the time of the study.The city's rat population is dominated by the brown rat. The average brown rat grows to be 16 inches (410 mm) long and weigh 1 pound (0.45 kg), though some have been known to grow to be 20 inches (510 mm) long and weigh 2 pounds (0.91 kg). The rat can squeeze through holes or gaps the size of a quarter (0.955 inches (24.3 mm), leap 4 feet (1.2 m) sideways, drop down five stories without getting injured, and an adult rat can tread water for three days. The rats are able to chew through pipe and cinder block. Each litter has up to a dozen pups, and newborn rats can mate at the age of two or three months and produce a new litter every two months. The rats live about a year.New York City rats carry pathogens that can cause serious illness, diarrhea, vomiting, and fever in humans, especially in children, with symptoms that can range from mild to severe. The pathogens that they carry include bacteria that cause food poisoning (e.g., Salmonella and a strain of E. coli that causes terrible diarrhea) and dermatitis, pathogens that cause fevers (such as Leptospira), viruses from groups that contain important human pathogens including E. coli, serious and sometimes fatal rat-bite fever, Clostridium difficile (C. diff), sapoviruses, cardioviruses, kobuviruses, parechoviruses, rotaviruses, hepaciviruses, bubonic plague, typhus, spotted fever, Bartonella pathogens (which can cause a wide range of clinical syndromes in humans, some severe, including cat scratch disease, trench fever, and Carron disease), and Seoul hantavirus (which can cause hemorrhagic fever). These bacteria typically spread when rats leave behind saliva, urine, or feces that humans or their pets come into contact with. In addition, the rats carry fleas (including Oriental rat fleas), lice, and mites that can carry bacteria that can cause serious diseases in humans. In addition to disease risks, higher risk of allergies and asthma is linked to exposure to rodent hair, droppings, and urine, especially in children.New York City rodent complaints can be made online, or by dialing 311, and the New York City guide Preventing Rats on Your Property discusses how the New York City Health Department inspects private and public properties for rats. Property owners that fail inspections receive a Commissioner's Order and have five days to correct the problem. If after five days the property fails a second inspection, the owner receives a Notice of Violation and possibly fines. If the Health Department feels it must itself exterminate or clean up the property, the property owner is billed.