Researcher David Armitage, writing on the University of Michigan Department of Zoology's Animal Diversity Web site, claims that the brown rat is responsible for more deaths than all the wars of the world combined. The brown rat (Rattus norvegicus) is host to lice and fleas that carry serious illnesses including the bubonic plague, even today. That's something to think about. Brown rats are an adaptable species that can live just about anywhere you do. They may live in your home, but they're still wild.
The brown rat, also known as the Norway rat, originated in China and spread to Eastern Europe in the early 18th century. By 1800, every European country was home to the brown rat. The first appearance of the brown rat in the United States was in 1770s. It is believed that the species came to America on cargo ships.
The brown rat measures roughly 15.7 inches long and has an average weight of 14.1 ounces. Males are often larger than the females of the species. Their brown fur may be spotted with white or black hairs. The underside of the rat is usually gray or tan in color. In the wild, the lifespan of the species is around two years.
In rural areas, the brown rat inhabits forests, open fields and brushy areas. Nocturnal in nature, the rat may live in burrows or hollowed-out logs during the day. The species will stay in a relatively small area as long as food remains plentiful. For example, rats may be content to live in the family garden during the warmer months but may seek food in a broader range during the colder months.
With female brown rats' ability to produce 60 offspring per year, some cities are overrun by the species. In many large cities, the brown rat is a nuisance that has a large supply of food thanks to city sanitation or lack thereof. The urban brown rat makes its home in basements, city dumps, sewers and anywhere else food may be plentiful and easy to get to. Those that have homes that are easy for the rats to access may have trouble getting rid of them. Signs of a rat infestation include rat droppings and chewed food packages. The urban brown rat is still a wild rat. Only domesticated pet rats aren't wild.