Rats

Rats and mice can be described as "commensal" rodents (commensal literally means "sharing one's table"). This is a very apt description because wherever man has buildings and food there is potential for infestation by these animals.

Norway or Brown Rat (Rattus Norvegicus) and Ship or Black Rat (Rattus Rattus)

In Britain there are two species of rat. The most widespread and abundant of these is the “Common Rat” (also known as the Norway rat or sewer rat). It originated from China and was first recorded in Europe at the beginning of the 18th Century. It lives anywhere offering food and shelter including sewers. The “Ship Rat” (or black or roof rat) lives largely indoors in Britain mainly in the port areas.

Rats are excellent climbers, jumpers, swimmers and can easily squeeze through very small openings. The three most important things for a rat are: water for drinking (they can only live a few days without it!), a food source and harbourage. A common rat is usually suspicious of and tends to avoid any new object that it comes across such as a bait station, this is called Neophobia or New Object Reaction. In time the neophobia wears off but it may take 3-5 days or as long as 10 days to enter a bait container. In contrast mice tend to explore rather than avoid new objects. They will therefore feed more freely on baits from the start.

Most people detest rats mostly because it is known they spread disease, contaminate foodstuff and cause serious damage to buildings and materials.

The word rodent comes from a Latin word that means to gnaw. Rodents gnaw with their paired incisor teeth. Rodents need to continually gnaw on solid objects. Rodent damage to buildings can prove extremely costly. Rodents gnawing on cables or wires could start a fire.

Common rat colonies typically develop from a pair or single pregnant female. Infestations can develop very quickly from a single pair. Optimum conditions are equable temperature, surplus food with adequate water and undisturbed cover for rearing young.

Rats are sexually mature at 3-4 months old, they give birth every 24-28 days with an average litter size of 6-11 young and can produce 4-6 litters a year.