Rats are commensal rodents this means they happily live in close association with us humans sharing our homes and food.
Rats are a common pest in the U.K; they can cause structural damage by gnawing and burrowing, spread diseases, some of which are life threatening to both humans and livestock, and contaminate stored products with their urine, faeces and hair. This damage can be costly. Fires can easily be started from a gnawed a cable, burrowing can undermine foundations of buildings, gas and water mains, and damage caused to water courses and sewers can lead to flooding.
It is estimated rats in the UK consume 210 tonnes of food per day.
The two most common species of rat found in the U.K are the Norway rat (Rattus norvegicus). And the less common species, the Black or Roof rat, (Rattus rattus), which is largely restricted to port areas.
The brown rat (rattus norvegicus) is also known as the Norway rat or sewer rat.
The average adult body length is around 250mm and weighs about 300 grams, the tail is shorter than the body, the snout is blunt and rounded and the ears are short, the fur can be brown or black on the head and upper body and grey to off white underneath.
The brown rat is an excellent swimmer and water voles are often mistaken for rats, so before carrying out any rodent control be sure you have made the correct identification.
The brown rat does burrow and will happily live outdoors but given the opportunity will readily move indoors especially during the winter months, sewers are another favourite home for the brown rat.
Brown rats can live up to 3 years but 9-18 months is the average they reach sexual maturity at 2-3 months. Litter sizes vary but on average it is around 8-10 and up to 7 litters per year can be produced.
The Black rat (rattus rattus) is also known as the ship rat or roof rat and is slightly smaller than the brown rat, with a body length of around 150-220mm and weighing about 200 grams. The tail of the black rat is usually longer than its head and body length combined, the snout is pointed and the ears are more prominent and hairless. The fur of the Black rat is smoother and softer than that of the brown rat and is normally black or grey in colour. Unlike the brown rat the black rat does not burrow and lives and nests in wall cavities, attics, vines and trees. It is very rarely found in sewers.
The life span of the Black rat is 9-18 months and reaches sexual maturity at 2-3 months. Litter sizes are around 6-10 with up to 6 litters per year.