Brown rat

The brown rat (Rattus norvegicus), also known as the Norway rat, common rat, street rat, sewer rat, or Hanover rat, is a widespread species of rat. One of the largest muroids, it is a dominant and successful commensal rodent, meaning it readily lives in close association with humans.

Description:

Brown rats are robust animals with a blunt snout, small ears, and a tail shorter than the body. Their fur is typically coarse and brown or grey, but color variations exist. They are larger than the black rat (Rattus rattus), generally weighing between 140 and 500 grams (5 to 18 ounces).

Distribution and Habitat:

Originating in northern China, the brown rat has spread to nearly all parts of the world, primarily accompanying humans on ships and through trade routes. They are adaptable and thrive in various habitats, including urban and rural environments, particularly wherever food and shelter are readily available. Common habitats include sewers, garbage dumps, fields, and buildings.

Behavior and Diet:

Brown rats are primarily nocturnal and exhibit social behavior, often living in colonies. They are omnivorous and opportunistic feeders, consuming a wide range of foods, including grains, seeds, fruits, vegetables, meat, and garbage. They are also known to scavenge. Their strong teeth allow them to gnaw through materials such as wood, plastic, and even soft metals.

Reproduction:

Brown rats are prolific breeders. Under favorable conditions, they can breed year-round, with females capable of producing several litters per year. Each litter typically contains 6-12 pups. The gestation period is approximately 21-23 days. Pups reach sexual maturity in about 2-3 months.

Relationship with Humans:

Brown rats are considered significant pests due to their ability to transmit diseases, contaminate food supplies, damage property, and displace native species. They are known carriers of various pathogens, including Leptospira, Salmonella, and Hantavirus. Control measures, such as trapping, poisoning, and sanitation, are often implemented to manage rat populations. Conversely, brown rats are also used as laboratory animals in scientific research due to their physiological similarities to humans. Selective breeding has led to the development of various laboratory rat strains.