Britain is home to two kinds or rats:

  • The common rat (or brown rat)

  • The ship rat (or black rat)

The adult common rat may weigh from 100 to 500 grammes and has brown fur on its back and grey underneath; its tail is shorter than its head and body. The ship rat, which is far less common, is between 100 and 300 grammes; it may have black or brown fur, has large almost hairless ears and has a tail which is longer than the head and body, giving it greater agility.


The common rat is the most abundant and widespread species and can be found anywhere that offers shelter and food - including sewers. They are efficient burrowers and favour compost heaps and the ground underneath hedges and sheds where they will dig shallow burrows and form nests with dry grass and leaves. In houses they will nest in wall cavities and beneath floor boards. Ship rats will normally be found indoors, mainly in port areas, but they may be transported inland, with cargo. Being agile climbers and jumpers, ship rats will often nest in roof spaces and upper floors.

Both species of rat are active mainly at night but may be seen in search of food and water during the day.


Rats are a major hazard to health. They spread many forms of disease, some of which cand be fatal to man such as Weil's Disease. They may eat food which is intended for human consumption and they often damage much more which has to be discarded. Through their gnawing habit they also cause considerable structural damage to woodwork, waterpipes, electric cables and so on.

Life cycle

The life expectancy of rats is around one year during which time a female will typically breed five times. The average size of a litter is between seven and eight. Breeding occurs throughout the year but especially in the Spring and Autumn.

Control of infestation

Their ability to burrow, climb and jump, and the speed with which they breed and form new colonies, make rats difficult to control.

Ensure that your premises are in good repair making it difficult for rats to gain access, and by removing any sources of food and water or clearing areas which may offer shelter or nesting materials such as piles of timber or any areas of your garden which are overgrown.

If you need help in treating a rat infestation or have any further questions, please contact SDK Environmental Limited (Trading as DialAPest) on 03444 828 325 between 9am and 5pm seven days a week. Calls to 03444 numbers are charged at a local rate.

Date of last review: 30 November 2015