As their alternative name suggests, they were commonly found on ships, resulting in their distribution throughout the world.

Life span
Up to 18 months.

Statistics
Body length: 10-24cm, Weight: 150-200g.

Physical description
Black rats are very similar in appearance to brown rats, but they are slimmer, with relatively larger ears and a longer tail. Despite their name, they are typically grey brown, with a pale grey underside, but they may be completely black.

Distribution
Although native to Asia, black rats have spread all over the world. They have largely been replaced by the brown rat in Britain.

Habitat
Black rats are highly adaptable and can be found in a variety of habitats, typically near human habituation.

Diet
They are omnivorous, but are more partial to fruit than brown rats are.

Behaviour
Black rats live in male dominated groups. Fights are common, often initiated by the females. They are predominantly nocturnal, but they will sometimes forage for food in the day.

As with brown rats, they have good auditory and olfactory senses, but black rats have better eyesight.

Reproduction
Most breeding activity occurs from March to November, and they produce 3-5 litters a year. Females give birth to 7-8 young after a gestation period of 23-24 days. They are weaned after 3-4 weeks.

Conservation status
Black rats are now one of the rarest mammals in the UK, but persist mainly around port towns, such as Liverpool, London, the Shiant Islands (Inner Hebrides) and Lundy island. They are subject to persistent pest control due to the damage they cause and the numerous diseases they spread, including bubonic plague, typhus and rabies.