How Did Rats Come to America?
WouterRats have long been a part of human cultures. The Europeans brought rodents to the New World, focusing on species with special affinity for humans. Rats now exist in North America in numbers that exceed seventy species. While most people are familiar with the black rat (Rattus rattus) or the Norway rat (Rattus norvegicus), there are dozens of other species and varieties.
During the medieval period, rats helped spread the Black Death throughout Europe. It was carried by fleas on the black rats, and millions of people became infected with the plague each time the rodents infested a city. Rats arrived in America around 1776, when brown rats were introduced in food supplies and boxes. The rats travelled long distances on foot by following drainage pipes and sewers, and even swam to reach a new area.
Rats were first introduced to laboratories in 1828. In the 1870s, a scientist named John B. Calhoun started experiments with these rodents to study the effects of overpopulation. Rats were chosen as a symbol of urban degeneration and were used in experiments as a means to study the effects of this problem.
Today, Norway rats have spread throughout the contiguous 48 states and have been associated with human cultures for centuries. Some researchers believe they were brought here on ships during the crusades. This species is dark brown to black, has a blunt snout, and a bald tail. While they’re native to Asia, they’re now widespread throughout the contiguous 48 states.
