The Arrival of the Norway Rat (Brown Rat) in Europe (1553) and Its Global Impact

The Norway Rat (Rattus norvegicus), also known as the Brown Rat, was first recorded in Europe in 1553. Although its name suggests a Norwegian origin, this is a misconception. The rat likely originated in eastern Asia, possibly northern China, and spread to Europe and beyond through trade and human migration.

Origins and Misnaming of the Norway Rat

• The name "Norway Rat" was given in 1769 by John Berkenhout in Outlines of the Natural History of Great Britain, mistakenly believing it arrived in England on Norwegian ships in 1728.
• However, at that time, no Brown Rats had yet reached Norway, and they more likely arrived from Denmark.

Comparison with the Black Rat (Rattus rattus)

• The Brown Rat is larger, more aggressive, and more adaptable than the Black Rat (or Roof Rat, Rattus rattus).
• While Black Rats were historically associated with the spread of bubonic plague, Brown Rats rarely, if ever, carried the disease.
• The Brown Rat’s dominance over the Black Rat in Europe began in the 18th century, as Brown Rats outcompeted Black Rats for resources.

Diseases Carried by Brown Rats

Although not a primary vector of bubonic plague, Brown Rats can transmit several diseases, including:

• Weil’s Disease (Leptospirosis)
• Cryptosporidiosis
• Viral Hemorrhagic Fever (VHF)
• Q Fever
• Hantavirus Pulmonary Syndrome

Their close association with human populations makes them a major concern for public health, especially in urban environments.

The Global Spread and Impact of the Brown Rat

• The Brown Rat is now found on every continent except Antarctica.
• Due to its incredible adaptability, it is considered one of the most successful mammals on the planet, alongside humans.
• It thrives in cities, sewers, and food storage areas, making it a permanent feature of human civilization.

The Brown Rat’s Role in Science and Domestication

• Selective breeding has led to two key developments:
  1. The Fancy Rat – A domesticated variety bred as a pet.
  2. The Laboratory Rat – Widely used in biological and medical research.
• Laboratory rats have been critical for scientific discoveries, including studies in genetics, psychology, and disease treatments.

Conclusion: The Brown Rat’s Unstoppable Expansion

First documented in Europe in 1553, the Brown Rat has become one of the most widespread and resilient mammals in the world. Its ability to adapt to urban environments, displace other rat species, and spread alongside human settlements makes it a defining species of human history, whether as a pest, pet, or scientific model organism.