Latest news:

Brown rat, Norway rat

Scientific name: Rattus norvegicus

Country: Worldwide, originally China.

Continent: Europe, Asia, Oceania, Africa, South America, Central and North America

Diet: Will eat almost anything dead or alive, including insects, fish, carrion, vegetables, grain, soap and leather. At the Zoo, they receive a dry rodent mix and some fruit and vegetables.

Food & feeding: Omnivore

Habitats: All (in association with humans).

Conservation status: Not threatened

Relatives: Black rat, capybara, squirrel, hamster.

Description: The brown rat is larger than the black rat and is not as agile a climber. An average brown rat weighs about 400 g and has a body 250 mm long plus a long tail. Sharp claws, long sensitive whiskers and powerful teeth make this little omnivore ready for almost any meal.

Lifestyle: Brown rats tend to be outdoor animals and will infest the areas around a building rather than the building itself. They can create extensive burrow systems but will take advantage of man-made tunnels, such as sewers. They live in extended family groups. Rats are very adaptable and quick to learn and so will exploit any food source, especially where we leave food where they can easily get at it. Wherever there are humans there will be rats not far away! On its nightly patrol a brown rat will venture out along a series of regular runways, perhaps up to 50 m from its nest, but will range up to five km for example, to reach fields at harvest time where spilt grain may be available.

Family & friends: Brown rats live in large loose groups with one male dominant over other males and females. When food is scarce, rats at the bottom of the heap may be forced to feed during the day time, which is often the only time we become aware that we are sharing our homes and gardens with these animals.

Keeping in touch: Like other rodents, brown rats use scent marking and high-pitched squeaks to keep in touch with other rats in their home range.

Growing up: Rats can breed very fast. A female can start reproducing at about three months old and produces 4-10 young in a litter, although larger numbers have been recorded. If there is plenty of food she may have a litter every four weeks. They are born naked and blind and depend on their mother for food and warmth, although they will be fully weaned within a month and will be able to breed themselves only two months later.

Some figures suggest that an amount of grain big enough to feed 400 million people is lost to rats each year, by both eating the grain and chewing their way into stores and fouling the grain.