There are two rat species in Britain; the brown rat and the black or ship rat. The brown rat is the biggest, often reaching around 23cm, not including the tail. It has a blunt muzzle, small, hair-covered ears and a tail that’s shorter than its body length. The black rat isn’t as plump and is slightly shorter. It has a pointed muzzle, large, almost hairless ears and a long, thin tail that’s longer than its body.

Brown rats are more common than black rats and stay near ground level. Black rats are more often found in seaport towns and are more agile, often entering buildings by the upper floors.

Both species breed rapidly. A female rat  may produce up to around 90 offspring each year.