Rats

Pest Name: Brown Rat- - Rattus norvegicus

Markings: Grey/Brown or black fur, slightly lighter undersides.

Location: Just about anywhere man is found, and more.

Detection: Customer will report live sightings, scuffling noises, droppings and gnawed goods, smell. Nesting materials sometimes seen.
Britain is host to two species of rat, Rattus norvegicus (the Brown or sewer rat) and Rattus rattus (the Black or ship rat).

Many signs of infestation may occur, droppings being the first possible sign followed by gnawing.  Damage to fabrics, excavations around or under buildings, well worn runs through undergrowth or smear marks (a dark mark caused by body grease) over surfaces which are crossed regularly are other tell tale signs.  Where infestations occur near water courses holes will often be present in the banks as this offers an excellent escape route as rats are accomplished swimmers.

General Information: Size - 19 - 28 cm (head & body).  Tail 60% body length.  100 - 500 g (average about 350g).

The Brown Rat is the newcomer to our shores, arriving several hundred years ago from Asia. Weighing 100 - 500 grammes, its upper parts are dark brown becoming lighter brown to grey or even white on the under parts. The tail is shorter than the head and body and the head and face are quite blunt in appearance.

The Black rat is far less common and restricted to 3 major ports. Its appearance is sleeker with a body weight between 100 - 300 grammes with brown to black fur, large almost hairless ears and a tail, which is longer than its head and body. This enables it to be very agile and an excellent climber which gives rise to its other name “Roof Rat ".

Rats have five senses like humans, with particularly well-developed hearing, smell and touch, but they are colour blind.  They do have good movement detection.

Biology: The life expectancy of a wild brown rat is approximately 10-14 months in which time the female will typically breed between 5 and 7 times, with an average litter size between 7 and 8 young. Breeding can occur throughout the year depending more on the availability of food and harbourages than on weather conditions. Around 800 offspring from one pair of rats is possible, under ideal conditions. Both species are most active at night but may be seen in search of food and water during daylight hours.

Reasons for Control: Immense damage can be caused by rats feeding in warehouses, factories, shops and homes due to both quantities of food consumed, contamination by faeces and urine, and damage by gnawing.  Contamination and possible introduction of microorganisms, which can cause food poisoning, such as Salmonella, make this rodent a major public health pest.  Remember rats carry Weil's disease (Leptospirosis), which can cause serious illness.