The main types of rat are:
The adult rat weighs 300gms, with a body length of 200-300mm. Its fur is harsh and shaggy, with a colouring of brown and black on the upper head and body, grey or off-white underneath. Rats have an excellent sense of hearing, but have poor sight and are colour blind. They also possess an excellent sense of smell and taste.
The rat will burrow, lives outdoors, indoors and in sewers and nests in burrows. It can climb, though is not agile. The rat is a very good swimmer, and is relatively conservative being somewhat predictable in habit. It will avoid unfamiliar objects, e.g. bait trays placed on runs, for some days.
The rat is omnivorous, more likely to eat meat, and consumes up to 30 grams per day, and drinks water or eats food with high water content. The rat will live between 9-18 months and reaches sexual maturity at about 2-3 months. It produces a litter of 8-10 young and has up to 7 litters a year.
Rats are a worldwide pest due to their capacity to cause structural damage, to spread life-threatening diseases, and to compete with man for food.
The species most commonly found in Europe is known as the Norway Rat. A less commonly found species, the Black or Roof Rat, is largely restricted to port areas.
Rats live alongside humans, invading their buildings and eating their food. Rats transmit disease which are potentially fatal to humans such as Weil's disease and murine typhus. They also carry organisms which can damage human health such as Salmonella bacteria, viruses and parasites such as nematodes and worms.
Specialist rodenticides are the most effective means of controlling this pest, though rodenticides can be purchased from retail stores; these should be used strictly in compliance with the packet directions.