Brown Rats - Outline Biology and Habits
The
Brown rat, (Rattus norvegicus) is the main pest rat species in the U.K.
The black rat, (Rattus rattus) is rare and found only in a few dockside
locations. The information below focuses on the Brown rat.
The
droppings are 5-8mm long and usually occur in groups (latrines). They are usually a shiny black, but may vary according to the
diet.
Rats have strong teeth and powerful jaws and can cause damage to wooden materials, electrical wiring,
communication cables, plastics, rubber, even through mild steel. Gnawing
holes from rats are about 50 to 80mm in diameter, with rough edges.
Rat burrows can be found along foundations, or beneath rubbish and shubbery. If the burrow is active it is usually clear of vegetation. Rat runways are smooth and well packed. Indoors, these runways are free of dust and dirt.
They
prefer foods with a high protein or carbohydrate content, but will eat
almost any type of food and unlike mice, they need to drink water to
survive. They will eat around 30g of food daily and drink up to 60ml of
water.
The
young rats reach sexual maturity in 10-12 weeks, females are capable of producing litters every 3 weeks, but this is dependent on the local conditions, with 7-8 young per litter and a gestation period of
about three weeks. Adults live about a year in colonies.
Needing
a water source, they can obtain water from toilets, sinks, rain
puddles, or condensation from utility pipes.
Their nesting burrows outside can be found along wall foundations, below rockeries and outbuildings. Indoors, locations such as basements, wall cavities, attic spaces and similar undisturbed areas are all possible nesting sites. Their nests are built from soft material like paper or grass chewed into small pieces.
Their nesting burrows outside can be found along wall foundations, below rockeries and outbuildings. Indoors, locations such as basements, wall cavities, attic spaces and similar undisturbed areas are all possible nesting sites. Their nests are built from soft material like paper or grass chewed into small pieces.
They
are well known to be active in sewers and it is quite often broken
sewer pipes (perhaps by tree roots or building work) that allows rats
easy access inside buildings.
Little known facts about the Brown Rat:
- Rats will climb if necessary, to enter a building or gain vertical advantage;
- They are excellent swimmers;
- They have specific toilet areas, which will used repeatedly by a colouny;
- They are also suspicious of changes in the environment or new foods; this is called Neophobia and for this reason it may take them several days to enter traps or or bait stations.
Rats
are nocturnal, with their peak activity at dusk or before dawn. When
the population is large or they are disturbed or hungry, you can see
activity during the day.
