Rattus norvegicus

Rattus norvegicus
Zeynel Cebeci · CC BY-SA 4.0 · source
Name	Brown rat
Status	Least Concern
Genus	Rattus
Species	norvegicus
Authority	Berkenhout, 1769

Rattus norvegicus is a common medium-sized rodent native to Asia but now globally distributed, notable for its commensal association with humans and its prominence in scientific research and urban ecology. It has been studied by figures and institutions such as Charles Darwin, Robert Koch, Louis Pasteur, University of Oxford, Harvard University, and features in collections at the British Museum, Smithsonian Institution, and Max Planck Society. Its ubiquity links it to historic events and places including the Great Fire of London, the Industrial Revolution, Port of London, New York City, Tokyo, and Saint Petersburg.

Taxonomy and etymology

Described in 1769 by James Berkenhout under modern binomial nomenclature, the species belongs to the genus Rattus within the family Muridae and the order Rodentia, and its naming history intersects with taxonomic work at institutions like the Linnean Society and the Royal Society. The specific epithet reflects 18th-century Latinization practices evident in other taxa cataloged by collectors associated with the British East India Company and explorers linked to Captain James Cook and Joseph Banks. Debates over subspecies and phylogeography have involved genetic studies from laboratories at Cold Spring Harbor Laboratory, ETH Zurich, and the Smithsonian Tropical Research Institute.

Description

Adults typically measure 20–25 cm body length with a similar tail length and weigh 200–500 g, characteristics documented in natural history collections at the American Museum of Natural History and the Muséum national d'Histoire naturelle. Pelage ranges from brown to gray with lighter underparts, a phenotype compared in comparative morphology studies by researchers at University College London, University of Cambridge, and University of Tokyo. Dental formulas and cranial measurements are used diagnostically in keys distributed by the International Union for Conservation of Nature and the World Health Organization, and anatomical atlases by publishers associated with Oxford University Press and Springer provide detailed osteology.

Distribution and habitat

Originally native to the steppes and river valleys of northern China and Mongolia, the species expanded worldwide via maritime trade routes controlled historically by entities like the Dutch East India Company, the British East India Company, and the Hanseatic League, reaching ports such as London, Amsterdam, Mumbai, Shanghai, and New York City. It inhabits urban sewers, agricultural granaries, riverbanks, and subway systems exemplified by the London Underground and the New York City Subway, with ecological studies conducted by teams from the University of California, Berkeley, University of Sydney, and the Max Planck Institute for Ornithology. Island invasions documented in conservation literature involve locations like Galápagos Islands, Falkland Islands, and New Zealand.

Behavior and ecology

Nocturnal and omnivorous, it forages on seeds, invertebrates, refuse, and foodstuffs from markets such as those in Istanbul, Bangkok, and Mexico City, with behavioral ecology work published by researchers at Princeton University, Stanford University, and the University of Toronto. Social structure includes hierarchical colonies with dominance behaviors observed in laboratory studies at Massachusetts Institute of Technology and field studies near Chernobyl funded by teams from the International Atomic Energy Agency and the University of Kiev. Predators include urban raptors like the Peregrine Falcon, mammals such as the Red Fox, and carnivores documented in regional faunal surveys by National Geographic Society and the World Wildlife Fund.

Reproduction and life cycle

Sexual maturity occurs at about 2–3 months with estrous cycles and litter sizes averaging 6–12 pups, data gathered in reproductive biology labs at Johns Hopkins University, Cornell University, and Cold Spring Harbor Laboratory. Gestation is approximately 21–23 days, and parental care patterns have been characterized in studies associated with the National Institutes of Health and the Wellcome Trust. Lifespan in the wild is typically under two years, while captive specimens maintained by institutions like the RSPCA and university vivaria can live longer, informing studies in developmental genetics and aging at Salk Institute and Max Planck Institute for Biology of Ageing.

Interaction with humans

Closely associated with human settlements, the species has influenced urban planning, public health policy, and cultural representations in literature and art, appearing in works connected to Victor Hugo, Charles Dickens, George Orwell, Edgar Allan Poe, and artworks displayed at the Tate Modern and the Museum of Modern Art. Its role in commerce and transport tied to ports such as Liverpool and Hamburg led to regulatory responses by municipal authorities like the London Metropolitan Board of Works and public health agencies including the Centers for Disease Control and Prevention and the European Centre for Disease Prevention and Control. It is also a major laboratory model used in biomedical research at institutions including National Institutes of Health, Howard Hughes Medical Institute, and the European Molecular Biology Laboratory.

Health, disease, and control methods

As a reservoir and vector, the species is associated with pathogens studied in infectious disease research by Robert Koch-era and modern laboratories at Pasteur Institute, Imperial College London, and Yale University; pathogens include strains implicated in leptospirosis, hantavirus, and bacterial zoonoses monitored by the World Health Organization and the Food and Agriculture Organization. Control methods encompass integrated pest management strategies employed by municipal programs in Paris, Tokyo, and Los Angeles involving sanitation measures, trapping, rodenticides regulated under laws such as those enacted by the European Commission and agencies like the US Environmental Protection Agency, and ethical considerations addressed by organizations like the Royal Society for the Prevention of Cruelty to Animals and animal welfare committees at universities.

Category:Rattus