A rat infestation can be recognised by droppings, gnaw marks, the smell of urine and noises. Outside, the large rat holes in the ground are conspicuous. If the infestation is more severe, rats can often be observed directly.
An adult Norway rat produces 40-50 chops a day. Even a few rats can produce literally thousands of pellets in a short time. These droppings are 10-30mm long, dark coloured and spindle-shaped, with blunt ends and one end thicker than the other. Therefore, rat droppings are probably the most obvious sign of a rat infestation. Norway rats always deposit their droppings in piles in the same places. Fresh droppings are black, shiny and soft. Older droppings are hard and lighter in colour. Rat droppings contain many hairs that are swallowed when grooming.
Rodents like rats have very distinctive incisors that grow back for life. An incisor of an adult rat is 2-3mm wide. Bites of rats consist of 2 parallel grooves, about 4mm wide in total.
With their distinctive gnawing instinct, rats destroy a wide variety of materials such as packaging, textiles, insulation materials, cables, pipes, wood, plastic, bricks, aluminium, copper and even cast iron. They use their strong cutting teeth to open food containers, extract nesting material, enlarge loopholes or simply grind them down when they are overlong. The holes that rats bite into the various materials have a diameter of at least 5cm and often have jagged frayed edges.
Their burrowing activity and the construction of earthworks also repeatedly cause damage to sewage pipes, subsidence of pavements and holes in dykes and dams.
When rats are active, they make noises by gnawing or running around, e.g. in hollow spaces of ceilings. As they are nocturnal, these noises can be particularly disturbing. However, it is difficult to distinguish whether these noises come from mice or rats. If the infestation is more severe or lasts longer, a pungent urine or ammonia odour will develop. Cats and dogs often show the places where rats run or hide by excited sniffing, exploring and scratching.
Norway rats mark their paths with urine and glandular secretions. This causes heavily frequented areas to turn dark and smell strongly. These scent trails serve as orientation in the dark. In addition, areas that are regularly walked on by rats can be easily recognised. There is no dust, leaves or other dirt on the paths.
Walkways and rat holes are always the best places to set traps!
Norway rats destroy large quantities of food and feed, not only directly by eating, but also by contamination with hair, saliva, urine and faeces.
Norway rats are harmful to health because they can be infected by a variety of pathogens that can also be transmitted to humans or farm animals, such as plague, salmonella, rat-bite disease, typhoid, cholera, dysentery, SARS, Hanta fever, rat spotted fever, foot-and-mouth disease, avian flu, swine fever, trichinosis, toxoplasmosis, tularaemia, and many more. In total, there are thought to be about 120 diseases that can be transmitted by rats. By living in sewers, on rubbish tips and in composting plants, combined with long migrations into settlements or stables, Norway rats come into contact with many germs and spread them over a wide area. The germs are transmitted through contact with the rodents' faeces, urine, saliva and hair. In addition, Norway rats can carry parasites such as fleas, ticks, mites and tapeworms into human dwellings.
Norway rats cause a wide range of damage. They destroy food and feed, destroy property by gnawing and burrowing, and transmit pathogens to humans, domestic animals and livestock. In the following chapter, methods for prevention and control are presented.
Rats settle when favourable conditions such as a good food supply or hiding places are available. Under such circumstances, mass reproduction occurs quickly. It is best to prevent this in advance.
Autumn, when the fields are harvested and the cold, wet weather sets in, is the best time to take action against rats. They leave their summer quarters and seek dry and warm shelter in and around buildings for the winter. It is best to catch or drive away rats before they have taken up residence in buildings.
Rats migrate e.g. through open or poorly closing doors and gates, but also through cellar windows, light shafts, air supply openings, pipe penetrations, cable ducts, cooling and ventilation systems or other openings in the façade. Rats need an opening of only 2-3cm to enter a building. Therefore, there are often many suitable access points along the building. To reliably keep rats out, all access points should be closed as far as possible.
SWISSINNO Rodent Stop Steel Wool is a quick and easy fix to plug wall openeings, holes and cracks.
Another important access is the sewer system. It happens again and again that a manhole cover is missing, a dead branch has not been closed or a drain pipe is damaged and rats have direct access into a building here. If there is an infestation of rats inside buildings, all connections should be checked and repaired if necessary. In very rare cases, it has also happened that rats have entered a building even when the sewage system is completely intact via the toilets. In this case, a "rat flap" can be installed on the main drainage pipe.
The most important attraction for rats is the availability of food. The all-important preventive measure is therefore the deprivation of food sources:
Do not store food, pet food and seeds in bags or boxes, but in rodent-proof containers. The most common cause of infestation in private gardens is bird food that has fallen on the ground. Avoid excessive feeding of birds. Rubbish must also be stored in rodent-proof containers. Food scraps do not belong on the compost heap or in the toilet. Only metal and glass can permanently withstand rats' teeth.
Do not provide nesting opportunities for rats. Bulky waste and other rubbish does not contain food, but it provides ideal hiding places and nesting opportunities and should therefore be disposed of.
The action radius of a rat pack can extend over several properties. In other words, the actual source of infestation may not be on one's own property. When searching for the causes of infestation, the neighbouring properties should always be included in the considerations, as far as possible.
Ultrasonic rodent repellers are suitable for scaring away rats and preventing them from entering buildings. With SWISSINNO devices, the high-frequency sound is constantly changed to prevent the rodents from getting used to the sound.
It is important to note that ultrasound does not propagate through walls. Therefore, for good effectiveness, ultrasound units must be placed in all affected rooms.
However, if an infestation already exists, the sole use of ultrasonic rodent repellers is not sufficient to get rid of the rats. These devices should always be used as part of an integrated pest control strategy. Food deprivation, clearance and cleaning measures, closure of access routes, traps and ultrasonic rodent traps are used together.
With rat traps you can control rats without poison and in a humane way. SWISSINNO rat traps are robust, precise, animal welfare compliant and can be used many times. Great advantages of rat traps are the reliable proof that the rat has been caught and the fact that the dead rats can be disposed of. If poison baits are used, there is no simple and clear control of success, because the dead rats are often not found, but decompose (smell, maggots!) in inaccessible places.
There are 3 types of rat traps that are commonly used: Snap traps, live traps and electronic traps.
The following table gives an overview of the different SWISSINNO rat traps:
Rats are not just big mice. They are fundamentally different in behaviour. Mice are easy to catch, but rats are not. Rats have an innate shyness towards traps and are generally very suspicious. They are also social animals that learn quickly from each other. You have to be very careful when trapping if you want to be successful. Any mistake will lead to trap shyness, in the worst case for the whole pack. Individual rats can still be caught well with traps. However, in the case of a larger infestation, comprehensive measures are necessary. It is not enough to simply set up traps.
Trapping - tips from the pros:
Chicken house with rat infestation, trap placed in the corner along a rat run and secured with a wire rope
Rat trap set outside:
1: treaded rat hole
2: Wood placed underneath so that trap stands straight and firm
3: The whole thing was covered with the tarpaulin so that no other animals could get to the trap.
Rat traps placed at rat hole on walkways:
2: inverted tray to shield the traps and allow access from the front onlyn
To date, poison baits are a fast and reliable method of rat control. SWISSINNO nevertheless advises against the use of poison baits for several reasons:
However, if a rat infestation cannot be eliminated despite the best trap application and all flanking measures, the use of poison baits should be considered.