The Brown Rat is considered one of the most serious mammalian pests ever known; it's opportunist lifestyle, intelligence, agility, omnivorous diet and prolific breeding potential make it one of the worlds most successful mammals. They carry dangerous diseases such as salmonella, weils disease and rat bite fever. Rats must be controlled as they cause serious damage to property and crops. Some rats have developed resistance to modern rodenticides and that resistance is expected to increase. Rats are very difficult to trap but relatively easy to poison with rodenticides.
Brown Rat: Description & Life Cycle
There are two types of rat in Britain, the Brown Rat and the Black Rat. The brown rat is by far the most common but both can be controlled using similar methods. The black rat tends to live in walls, trees and loft spaces. Here we will deal with the brown rat.
Brown Rat Description:
- about 25cm in body length with a scaly, hairless tail of a further 25cm
- rats have relatively poor vision but can see well in the dark
- they have a very acute sense of smell and hearing
- prefer to live in burrows outside but do occasionally live indoors
- rats can climb well and are excellent swimmers
- rats live for up to three years
- in mild conditions, or if living indoors, they can breed all year round
- otherwise, breeding occurs in the spring, summer and autumn
- gestation lasts about 21 days and the litter size is usually 7-9
- young are weaned after three weeks and reach sexual maturity at about 8 to 12 weeks
- female usually has 4 or 5 litters per year
Signs of infestation:
- rat droppings, which are about 20mm long and capsule shaped, usually grey or black in colour
- holes under sheds, in compost, in banks, under log piles etc
- distinct and continuous tracks between places of safety, trees, bushes, sheds etc.
- gnawed timber, cables, water pipes etc
- noises in the cavity walls and/or loft
- dirty grey 'smear marks' often left where they cross over solid objects like walls and timber
- footprints, often found in the mud alongside water courses
- visual, often as they feed under bird tables