This entry proposes to give advice on to how to get rid of rats from inside of a house. Most people will agree, charming as they are, rats are not welcome in certain places - houses in particular.
Before getting rid of rats there are a few prejudices to get rid of first:
'Rats observe the fate of their fellow rat. They will not step into a trap that another rat has already taken its last breath in.' Not really true. The Researcher of this entry once had a spring trap in his home. This trap caught and killed a dozen rats in the space of a week. After such loss of life, however, the furry friends caught on and decided to avoid the trap.
'Rats do not climb up to upper floors.' Just plain wrong. They do.
'Rats usually enter a flat by coming up through the toilet bowl.' Very unlikely. In most modern toilets this is avoided by some kind of trap door opening only in the flushing direction. So things can go down (as they should) but normally do not come up.
'Local councils pay a reward for every rat killed within their area.' This actually used to be the practice in some places in southern Germany, and elsewhere, but, alas, it is not the case anymore. Rat catchers were paid 'per tail' so they used to cut the tails off their victims and bring them to the city hall.
Basic Facts About Rats
The following are just a few basics you might want to know about rats in your house.
The classic black-furred rat with a pinkish, naked tail, known in Europe as the ordinary house rat or ship rat1 is almost extinct. Instead, in 99% of cases, if you happen to have rats in your house, they will belong to the species known as the wandering or brown rat2, which is more pleasing in outward appearance, having a lightish coffee-brown fur, a white belly and a brownish, slightly furry tail.
The presence of rats is usually detected by their faeces (their excrement). If you find faeces which looks somehow like black rice corns, you do not have rats, but mice. Rat faeces is much bigger, measuring about 1cm in length and 0.3 - 0.5cm in diameter. It can vary in colour and smell and is more round at one end and more pointed at the other end.
At War with Rats
Here is some accumulated wisdom garnered from a bitter fight:
Always think of the implausible. Apparently, rats' mindsets work differently, enabling them to do exactly that which you would never expect them to.
After spending about a day searching the flat for a hole, which would have served as an entrance for a rat, it was discovered that the rat had literally bitten its way through the floor, ie vertically through two inches of solid oak wood.
In other places rats have been reported to climb up drainpipes. There simply are very few things they definitely cannot do.
Consider whether it is worthwhile to take up the fight with a large rat community.
After the untimely death of quite a few of them in the rarely-used cellar, it was discovered that they had transferred most of their activity onto the staircase, the surroundings of the garbage containers and the bicycle shed - places where they caused a much bigger problem than before.
Avoid direct confrontation. When attacked, rats can actually decide to defend themselves by biting which can be harmful and dangerous given the diseases they transmit.
The best way to temporarily clear a place of rats - for instance, say a shed needs to be cleared out - is by making a noise. Good results have been obtained by playing British punk rock music on a cassette player at maximum volume. Wagner might also do an equally good job. If money is no object, there are devices on the market which emit high-pitched sounds that are apparently unbearable to rats.
After different experiments, we found out that the classic spring trap still works best. Poison is always a bit of a random thing and you can't really tell if it's worked. One further advantage of the trap is that you can dispose of the corpse; the smell of a poisoned rat decomposing is worse than what a dozen rats can do in a lifetime, and it is possible for the poison to move through the food chain. There are life traps on the market, where our friends are supposed to get caught alive without actually being hit. Usually the rats distrust these more than any other trap, and they will learn much faster about its danger. The classic spring trap can be found in a lot of varieties, some of them offering slight improvements on the basic type.
Most important is the size. Do not underestimate the power and size of your rats. Just in order to be sure the rat is actually killed, the trap's platform should measure at least 7cm x 13cm. A pencil hit by the metal axis should break. Don't set the trap in a way that it goes off very easily: they might let it off and then enjoy the food.
The Bait - Lots of experiments have been carried out on the proper way to attract rats to the trap. What is known, is that smell is the most important factor here. Cheese indeed does well, especially if it's smelly. Moist bread is reputed to work well too, although this has not been tested in experimental conditions. Good results have been observed with a lightly salted mix made from a very liquid cheese, mild liver paté and goose fat. Another food that gives good results is chocolate.
The Corpse - In Germany the veterinary stations offer a special service and come to your house to take the corpse away with them. They do, however, charge you for every corpse they take. Another way is to throw the corpse into a rubbish bin inside a plastic bag. Avoid throwing the corpse into publicly accessible litter boxes, as many things go through these, looking for food.