The brown rat Rattus norvegicus
Interestingly, wild brown rats typically live in the burrows which they dig in the riversides. The brown rat eats costal plants and small animals, such as terrestrial molluscs, insects, etc. Brown rats often swim and dive, staying in water for long periods, and even catching molluscs, diving beetles, and small fish. Brown rats are well adapted to semi-aquatic life as their hind feet are partially webbed. Brown rats have spread around the globe and now occur almost worldwide. They spread by passive dispersal, mostly as stowaways on ships. Due to their tendency to synanthropy, omnivorous feeding, high exploration activity, excellent learning abilities, and profound prolificacy, brown rats have perfectly adapted to the life in anthropogenic landscapes, in close association with humans. In cities, brown rats sometimes may live as high as on the 8th or 9th floor of the houses, but they prefer settling in the basements and lower floors of the living buildings or storage premises, where available food items and household waste provide sufficient food base. Brown rats living close to people would eat any available food stuff, as well as domestic waste or cattle and bird foods.
