A contentious character but as resourceful as they come, the brown rat arrived in the UK in the 18th century and has been a crafty resident of our towns, cities and woods ever since.
Common name: brown rat
Scientific name: Rattus norvegicus
Family: Muridae
Habitat: urban, parks and gardens, farmland, grassland, broadleaf and mixed woodland, hedgerows
Diet: seeds and grains, fruit, invertebrates, meat, general food scraps
Predators: domestic cats, foxes, owls
Origin: non-native
Brown rats have dark brown or greyish-brown fur, with a pointed snout and beady eyes. Growing larger than any British mouse, these rodents can reach a body length of 15-27cm, with very long, almost naked tails.
Not to be confused with: the water vole. Water voles can reach a similar size to brown rats but have a rounder appearance, with smaller ears and shorter, furrier tails.
Credit: John Bridges / WTML
As true omnivores, these voracious rodents will eat almost anything they can get their paws on and are highly opportunistic. Cereals form an important part of their diet, especially in agricultural habitats, but they will also eat fruit, seeds and eggs. Smaller animals such as invertebrates, small bird chicks, mice and even fish can be eaten, while food scraps of all kinds will be consumed in the urban environment.
Credit: John Bridges / WTML
Brown rats live in loose colonies usually dominated by larger males. Breeding is prolific and occurs throughout the year, with some rats having five litters or more during that period. Females can begin to breed from as young as four months old, typically producing 6-11 pups in a litter. The pups are born blind and hairless, and are weaned at about three weeks old.
Brown rats are very strong swimmers and have been known to dive for molluscs in rivers where this food source is abundant.
Brown rats can be found across much of the UK and live in a wide variety of habitats, with the exception of mountainous regions. They are most common in towns and cities, drawn in by the temptations of bins, compost heaps and other places where leftover food goes begging.
Away from urban life, farms and hedgerows are ideal locations for rats, but they will make the most of anywhere they can construct their warren-like burrows.
Maligned for being dirty and diseased, brown rats actually keep themselves very clean and will spend hours grooming themselves.
Their love for the concrete refuges we’ve created means the best chance you have of spotting a brown rat is probably taking a peek at the bins outside your local restaurant. In rural areas, sheds and old farm buildings make for ideal rat shelters. The species is most active after dark and will leave small, tell-tale droppings that are blunt at one end and pointed at the other.
Credit: John Bridges / WTML
Its incredible adaptability means the brown rat is very common in the UK and is not considered to be at any risk. The species is often persecuted as a pest and has been subject to eradication programs on various islands around the world, including in the UK, due to the threat it poses to native seabird colonies.
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