Rats

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Last revised: 22 November 2007

A Picture of a Rat

Description

Although there are different types of rats in this country, problems with rats in this area are most likely to be due to the brown rat, also known as the common rat (Rattus norvegicus).

The adult common rat can weigh up to 1lb in weight, and grow up to one foot (30cm) in length. Rats live for about one year and the females can produce up to six litters a year, with a litter size on average of six to eleven. Typically, the common rat is brownish grey on the back and grey underneath, but the colour does vary and black forms have also been found.

Distribution

The common rat has been recorded in Britain since early in the eighteenth century and was thought to have been introduced by shipping.

The common rat can be found anywhere that offers food and shelter, which can also include drains and sewers. They will burrow into hedgerows, compost heaps and under garden sheds, where they will make nests.

If they get into houses they can be found in the roof space, under floors and inside cavity walls. Rats are mainly active at night but can be seen during the day searching for food.

Life cycle

Rats breed efficiently and a female rat of eight to twelve weeks old can produce four to six litters of young a year, with a litter size on average of six to eleven young.

If conditions are favourable for the survival of the young the female can conceive again soon after the litter is born. The young are born blind and helpless but by fourteen days old they are covered in fur, the eyes are open and the incisor teeth are showing.Rats generally live for less than one year and only a very small percent will live to a year or longer.

Significance

Rats can be hazardous to health. They are responsible for the spread of many diseases including Weil’s disease and salmonella. If you are bitten by a rat you should seek medical attention. They will also contaminate food with urine, droppings and fur. They can also cause considerable damage by gnawing at woodwork, water pipes, electric cables and household items.

Control Methods

If you think you have a rat problem then you will need professional help in controlling the infestation. The first indications of a problem are likely to be damage to the property, droppings (oval in shape ½” to ¾” in length) and holes appearing in the ground. However the following simple rules may help to minimise the risk of an infestation:-

  • Do not leave any excess food waste outside overnight, and place all household rubbish in the dustbin, keep the lid shut.

  • Remove any potential food (i.e. bird food), water sources and harbourage (i.e. rubbish) from the garden.

  • Ensure that any broken drains, sewer pipes or covers are either replaced or repaired as soon as possible.

  • Repair all holes in brickwork, air vents and gaps under doors should be reduced in size to 6mm or less.

  • Ideally sheds should be placed upon concrete blocks at least 6” off the ground.

Rats are more common than you think. If you see a rat in your garden on one occasion, there is generally no need for professional treatment. By paying attention to the above points, you are most likely to be able to solve the cause of the problem and that may be the end of the matter.

If you continue to see rats or there is clear evidence in the garden of the presence of rats, such as holes, excavated soil under sheds, runs or droppings, the Council does offer a service to treat rats and further information on charges can be found on the Council website or follow this link. Rats

Independent pest control companies also offer professional treatment of rats and their details can be found in local telephone directories and Yellow Pages.