Rats

Advice about rats

Here in the UK we have two species of rat. The common rat or brown rat (rattus norvegicus) is the one we usually encounter. The adult rat is usually fairly substantial and is not to be confused with a mouse that is much, much smaller. An adult will weigh up to 500 grams and is typically 200-270 mm long. Its fur can be various colours ranging from black through to white, but they are most commonly grey. Its tail is thick and leathery and is shorter than its head and body.   The ship rat or black rat (rattus rattus) is much less common.   It is darker in colour, slightly smaller but with a longer tail and is more agile than the common rat.

Common rats are widespread in cities.   You may find them anywhere offering shelter, water and food. They are often associated with sewers and in fact they find pretty much everything they need inside a sewer. Rats can climb and jump and are efficient burrowers forming holes which average 100mm in diameter. Sometimes a complicated tunnel system with several openings is produced. Such systems can be found on any open land including embankments, rubbish tips and domestic gardens. Although rats are generally most active at night, you may well see them foraging for food and water during the day.

There is no doubt that rats can be a major public health hazard. In the U.K.today there are many rat-borne diseases, examples are Weil’s disease (a rare infection which starts with influenza like symptoms which can be fatal) and salmonellosis (a food-borne illness causing diarrhoea and vomiting). Rats cause structural damage by gnawing and burrowing activities. Electricity cables and lead pipes are easily gnawed, and fires can be caused by rats gnawing through cables.   Rats can burrow under foundations of buildings and damage drains and sewers. They eat and contaminate human food which if plentiful will be only partially eaten leaving the bulk contaminated and needing to be destroyed. They contaminate food with their droppings, urine and hair.   You must not ignore an infestation and it should not be left untreated.

Rats live for up to a year, during which time a female will typically breed five times. The average size of a litter is between six and ten. Breeding occurs throughout the year, but especially in the spring and autumn.

As always, prevention is better than the cure.   You should ensure that your premises are in good repair - seal any gaps around pipes going through walls, repair broken air bricks, check and repair defective or faulty drains and never leave drainage exposed or manholes open.   Rats will emerge from the sewer and quickly colonise the area. You should deny rats food and water, clear up spillages of food thoroughly, and dispose of waste responsibly. Bird food can easily support a family of rats, so use a bird table with a rat proof support.   

Rats need to drink on a regular basis, so ensure water is not allowed to gather in such items as seed trays and flowerpots etc. Eliminate shelters and breeding areas clear areas that may offer shelter, or nesting materials such as piles of timber or any areas of garden that are overgrown. 

If you have a problem with rats you are most likely to need the help of a professional pest control technician. Their proven ability to burrow, climb and jump, and the speed with which they breed, make them difficult for you to treat on your own.