General Information
Perhaps the most disliked pest species of all, there are an estimated 60 million rats in the UK – that’s one for each person. Most of them are Common Rats (sometimes called the Brown Rat) with the second species being the Ship Rat.
The Common Rat is a supreme generalist; its opportunistic lifestyle, agility and prolific breeding potential have helped it to colonise practically every part of the world.
The average lifespan of a rat is 18 months and one pair can produce a colony of 2,000 rats in a year. In order to produce at such an alarming rate, up to 30% of the female rat population is pregnant at any time. Females become sexually mature at just 8-12 weeks, gestation is between 21 and 23 days, and females are able to conceive whilst suckling a previous litter, often mating within 18 hours of giving birth. They can breed throughout the year if the weather is mild and there is plenty of food. Up to 13 litters are possible each year, each one consisting of 7-9 young.
They eat the equivalent of 10% of their body weight daily, consuming rubbish, leftover dog food, bird food and even dog excrement.
Rats are largely nocturnal but will feed in the day time if there is enough food laying around in our streets or alley ways. So if you see a rat during the day time it’s probably because it’s been feeding on dumped household waste.
Rats often take up residence in areas near water, as they are excellent swimmers.
The Common Rat is believed to have originated from China. It reached Europe at some point in the early 18th century and was first seen in England in 1720. At present it has a very wide distribution in Britain in both urban and rural areas, but is absent from a number of smaller islands. It is widespread and common in urban areas across the globe, with the exception of some tropical and subtropical areas
Identification
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The Common Rat
The Common Rat is usually brown, though sometimes black. Length is 20-26cm for the head and body, with a further 17-23cm for the tail. The tail is virtually naked of fur and rather thick in appearance. |
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The Ship Rat
The Ship Rat is smaller than the Common Rat at around 16-23cm in length excluding the tail. Colour is more variable than the Common Rat and varies between black, brown and grey |
Signs that Rats are present
Given their relatively large size compared to a mouse, it’s fairly likely that a rat will be seen if they are present in a garden or house. However, signs are:
- Droppings – 10mm spindle shaped, usually round corners
- Unusual smells – a longstanding problem can create a stale smell
- Holes – which appear in the garden, approx. 7-12cm in size with a pile of earth near the entrance.
- Rat runs – a continuous depression in grass or other low vegetation, a smooth pathway may be visible on bare earth.
- Gnawing – often to the bottom of wooden doors and sheds.
- Scattering – of compost being dragged out of bins or heaps.
Risks posed by rats
Rats can be a serious risk to health. They will destroy and contaminate food stores, and carry many forms of disease including salmonella and Weils Disease through their droppings and urine. These conditions can be fatal to humans, although this is very rare.
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