Research has shown that brown rats arrived in North America earlier than previously believed, likely before 1740. They quickly overtook black rats, which had arrived with Columbus and thrived in colonial cities, within a matter of decades. Brown rats are larger and more aggressive than black rats and have a preference for living near human populations. This has led them to become known as common rats, street rats, or sewer rats.
The recent study, published in the journal Science Advances, analyzed rodent bones from 32 settlements in eastern North America and the Gulf of Mexico dating from the 1600s to the 1900s, as well as samples from seven shipwrecks dating from about 1550 to 1770. Researchers found that shipping networks across the Atlantic Ocean served as rat superhighways, allowing brown rats to establish themselves in coastal shipping centers. Their domination may have been due to their ability to outcompete black rats for food sources.
Today, both black and brown rats can be found in North American cities, with brown rats being more prevalent. These rodents are known carriers of diseases such as leptospirosis, murine typhus, and salmonella. In urban centers like New York City, efforts are being made to control rat populations, with measures focusing on reducing food waste to limit rat habitat. Brown rats are more likely to be found on the ground, while black rats prefer higher spots like trees.
Experts emphasize the importance of reducing food sources for rats to control their populations effectively. A “rat czar” was hired in New York City last year to address the growing rat problem in the city. By understanding the behaviors and preferences of both types of rats, cities can better manage pest control strategies. Brown rats, in particular, are attracted to animal products in food waste, so reducing these offerings can help deter them from urban areas.
Knowing the historical timeline of brown rat arrival and dominance in North America can inform pest management strategies to control rat populations in cities. Efforts to prevent rats from accessing food sources are crucial in minimizing their presence. By understanding the behaviors and preferences of brown rats, cities can implement effective measures to reduce their impact on urban environments. Brown rats’ preference for ground-level habitats and animal products in food waste can guide pest control efforts to limit their populations.
