ROMSO Cyprus Knowledge Base

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The brown rat (Rattus norvegicus) is a species of rat. It is a rough rodent of the Muridae family. It has a long body about the same size and a tail about the same size. Adult, it weighs about. It is therefore larger and heavier than its close relative the black rat (Rattus rattus).

It is called a brown rat, a sewage rat, a Norwegian rat or a grey rat to distinguish it from a black rat.

Like all rats of the genus Rattus, the brown rat is native to the Far East, specifically China. It is the most northern of rats, most of which live under the tropics and equator. It spreads to Europe through the steppes of Central Asia much later than the black rat, since the first are reported on the Old Continent in ; However, it is especially during the course of its massive invasion of Europe. The brown rat is now present on all continents except Antarctica. He lives in contact with human beings and especially in urban areas equipped with sewers. It is a nocturnal, carnivorous omnivorous animal that feeds on urban waste. Most of the brown rats nest in sewers, which provide them with predator-free shelter and nesting opportunities, hence the name "sewer rat". Gregary, the brown rat usually lives in very hierarchical groups.

Extremely prolific, this species is known as a possible vector of many diseases, making the brown rat a harmful and potentially invasive animal, as well as several other species of rats. However, this intelligent, sociable and easy to tame rat is also the strain species of the domestic farmed rat. Used mainly in experimentation as a laboratory animal and model organism, it is also a pet animal whose success is growing.

Description of species

Physical characteristics

The adult rat has a size not counting the tail. Its tail is of a length of . The tail of the brown rat is therefore shorter than its body (including its head), while the black rat is smaller and has a longer tail than its body.

The different studies consulted reported body weights of 200 to more for adult rats, with male rats generally larger and larger than females. Brown rats living in urban areas are larger than rats living in rural areas. Similarly, domestic rats have a higher body mass than wild rats, with a large variation in the size and weight ratio among the strains.

The brown rat in the wild has a brownish grey colour on the back and whitish grey on the belly, while the domestic rat may have different colours, markings and mutations. Black animals are also found.

The brown rat has a pointed and fine head, topped laterally by two rather small ears, the snout in