brunråttan

Brunråttan, or the brown rat (Rattus norvegicus), is a large rodent in the family Muridae. It is one of the most widespread mammals worldwide, originally native to northern China and the Far East, but introduced globally through human activity. It is often confused with the black rat (Rattus rattus).

Description: Adults typically measure about 20–25 cm in body length, with a tail of similar length. Weight commonly ranges from 200 to 500 grams. The fur is brownish-gray, the snout is blunt, and the ears are relatively small. The species is robust, agile, and adapted to a variety of environments.

Distribution and habitat: Brown rats are highly adaptable and occupy urban areas, farms, rural edges, and wild habitats. They commonly live in buildings and sewers, but also nest in burrows near water, fields, and grain stores. They have a cosmopolitan distribution, found on most continents.

Behavior and ecology: These rats are primarily nocturnal and social, living in colonies with complex burrow systems or structures near human activity. They are omnivorous, feeding on cereals, meat, discarded food, and various plant materials. They are strong climbers and swimmers and can traverse long distances by following scent trails.

Reproduction: Females reach sexual maturity at around 5–6 weeks. Gestation lasts about 21–23 days, and litters typically number 6–12 pups. A female may produce several litters per year, leading to rapid population growth under favorable conditions.

Impact and control: Brunråttan is considered a major pest due to damage to crops and stored foods, contamination, and the potential to transmit diseases. Control measures emphasize sanitation, exclusion of entry points, trapping, and, when necessary, chemical controls. Professional pest management is often required for infestations.

Conservation status: IUCN lists as Least Concern due to its extensive distribution and adaptability.