House MouseHouse Mouse



Occurrence: Worldwide with humans; Populations living in buildings all year round (e.g. houses, grain stores, stables, food shops, underground tunnels). In warm countries, house mice can also be found outdoors all year round and build truly wild populations, independent of humans. In central Europe mice only live outdoors in summer and migrate into buildings in autumn / winter. House mice are highly adaptable and are found in and around homes and commercial structures, as well as in open fields and agricultural lands.

Nest Location: always near a food source (Less than 10m away) in mainly following locations:

  • Attics
  • Garages
  • Garden sheds
  • Basements
  • Ceiling, floor and wall voids, often near corners and heat sources
  • Corners in cluttered areas
  • Beneath cabinets
  • Furniture voids - couches, chairs, dressers
  • Bases of kitchen furniture and appliances
  • Cluttered, neglected drawers
  • Storage boxes

Nests are padded with soft materials like shredded paper, textiles, hair etc.

Lifestyle / behaviour

The house mouse is native to India. About 15,000 years ago, when humans began to stock up, the house mouse adapted to humans and tried to steal their food. In the period from 12,000 BC to 1000BC it spread over all Europe. During the European exploration and colonisation, it has been transported by humans to the Americas, Australia and all other parts of the globe.

Active Periods: Nocturnal to protect against their natural enemies; activity peaks 30 minutes after sunset and before sunrise

House mice live in family groups. Their social behaviour is also highly adaptive and can range from polygamic (one male mates with several female) to polyandric (one female mates with several male) depending on population density. But most of the time, a dominant male lives together with a little harem of related females and their offspring. These groups of female cooperatively nurse, breed and rear with high reproductive success. The male mark their small territories with urine and defend them aggressively against intruders.

Social behaviour of house mice is managed by pheromones in their urine and tear fluid. For example. pheromones can slow down or speed up sexual maturation, synchronize reproductive cycles or even terminate pregnancies. Avoidance of inbreeding is also controlled by the urine scent. Closely related mice recognize each other by their scent and don’t mate.

House mice are good jumpers, climbers and swimmers. They can jump vertically up to 45cm.

They like to gnaw in different places and often. Small amounts of food are ingested in different places. Not only food but also other materials are gnawed (building materials, Styrofoam, wood, paper, cables).

As many rodents, mice have reduced ability to recognize colours,but have excellent night view. Additionally, they can see infrared light as well as ultraviolet light. So they are able to recognize the spotlight of trail cameras.

In the dark, they orientate by whiskers and body hair along walls and other vertical surfaces. They also follow their urine scented traces and smear marks.

Dark and smelly smear marks on strongly frequented mouse runway across beams and cables.

House mice have an excellent hearing and are sensitive to ultrasonic sound up to 120 kHz. During courtship, males sing ultrasonic songs for the female. Mouse baby calls are also in the ultrasonic range.

The tail is used for climbing, balancing, when standing on the hind legs and for thermoregulation.


Food: Cereal grains, meats, seeds. They prefer high-carbohydrate, plant-based foods, especially grains and grain products but are omnivorous. Inside of buildings food and feed of all kinds are accepted. In the wild, mice also eat insects, spiders and earthworms. Recent research showed that mice do not only destroy Styrofoam but also can digest it at a certain extent thanks to special gut bacteria.

2-4g of food is needed daily

Coming from arid regions, house mice require little or no water but utilize moisture in food. This helps them to live and survive indoors without having access to water.


House mice are characterized by a high rate of reproduction. A mouse couple can grow to a pack of 50-60 mice in three months. In winter, the increase is significantly lower than in spring and summer.

Mating usually starts between six and eight weeks of age. Once a pair successfully mates, it typically takes a little less than three weeks for the gestation period to be complete. The mother gives birth to between four and eight pups, although twice as many are possible.

  • Litter Size: 4 - 8 pups per litter
  • No. of Litters: 2 - 10 per year
  • Sexual Maturity: 1 - 2 month
  • Gestation Period: 18 - 20 days
  • Breeding Season: Indoors: All year; Outdoors: Spring to Fall


  • Scientific Name: Mus Musculus
  • Other Names: House Mouse
  • Colour: Back is dusty grey or brown grey or black, underside grey
  • Weight: Adults 15-25g
  • Body Length with tail: 15-20cm (tail same length as body)
  • Tail: up to 10cm, almost hairless
  • Body: Small head & slender body
  • Ears: Moderately large ears
  • Eyes: Small & protruding
  • Lifespan: 1-3 years
  • Droppings: 3-8mm long, dark colour

Manifestations & Damages


A mouse infestation can be recognized by droppings, gnaw marks, urine odours and sounds.

House mice are one of the most common rodents to infest human buildings. They destroy large quantities of food and feed, not only through direct consumption, but also through contamination with hair, saliva, urine and faeces.

Additional, damage is produced by gnawing materials like paper, cardboard, insulation material, packaging, textiles, cables, pipes and wood, be it for opening food containers, gaining nesting material, making slip throughs wider or simply to grind of the teeth.

House mice are harmful to health. Because they can be attacked by a variety of pathogens that can also be transmitted to humans like Rickettsialpox, Murine typhus, Leptospirosis and one severe type of Hanta virus. The germs are transmitted through contact with the faeces, urine, saliva and hair of the rodents. Furthermore, house mice can carry parasites like fleas, ticks, mites and tapeworms into human housings.


Droppings are the most encountered evidence of rodent activity. An adult house mouse typically produces 50 to 75 droppings per day. These faecal pellets are usually dark-coloured, 3 - 8mm in length, and pointed at both ends. Droppings are black when fresh, brown grey when older.

Even a small mouse infestation can produce literally thousands of droppings in a short time.

Gnaw Marks
  • House mice love to gnaw on various material. The gnaw marks and shredded materials are an additional evidence for the presence of mice. The width of the teeth marks can distinguish mice from rats: a mouse’s tooth is 0.5mm wide and a rat’s tooth 2-3mm.
  • Besides chewing wires, mice gnaw on plastic items, wood, corners of cereal boxes and bags. Additionally, they will shred paper and cardboard to gain nesting material.
  • Mouse damage holes are typically small, clean-cut holes about 1-2cm in diameter.
Sounds & Smells

When mice are active, they produce noise by gnawing or by running in ceiling or wall voids. Because of their nocturnal activity, these sounds can be especially annoying to the human inhabitants.

Mice continuously loose urine drops as they walk about. The smell helps the mice to orientate themselves in the dark. With a substantial or long lasting infestation, a strong smell will be detected. Cats and dogs owners may see their pets excitedly sniffing, probing and scratching places where mice have been.

Management and control measures

Conservation status: House mice are not protected.


Rodent population will increase in conditions that allow easy access to food and good protective shelter. This should be avoided.

The best time to act against mice is in autumn, when the fields have been harvested and the cold, wet weather sets in. The pests leave their summer quarters and look for dry and warm shelter in and on buildings for the winter. It is best to catch or drive away the rodents before they have established themselves in buildings.

It is always interesting to find out how the mice came into the building. Mice need an opening of only 6mm diameter to gain entry, so there are often many access points around the perimeter of a building. Mice penetrate mainly through open or poorly closing doors and gates, through basement windows, lightning shafts, air intake openings, pipe ducts, cable ducts, cooling and ventilation systems, outdoor lights, transformer stations, switch boxes and other apertures in outer walls. If possible, access points should be sealed to prevent future infestations. SWISSINNO Rodent Stop Steel Wool is a quick and easy fix to plug wall openeings, holes and cracks.

Mice are excellent climbers. Planted facades, wood cladding and insulation offer ideal climbing aids. Prevent nesting sites: piles of wood directly on house walls, bulky rubbish on the site, dense plant strips with ground cover around the building encourage the colonization of mice.

Eliminate nesting possibilities to discourage house mice from colonising the site. Get rid of piles of wood stacked against house walls, and of bulky rubbish on the site to make the area unattractive for nesting. 

Remove all food sources and avoid excessive bird feeding. Store foodstuffs, pet food and seeds in rodent-proof containers and not in bags or boxes.

Ultrasonic Repellents

Ultrasonic Rodent Repellents are an effective method of scaring mice away and preventing them from entering buildings. SWISSINNO Repellers emit high frequency sound waves in constantly changing patterns to prevent rodents from getting accustomed to the sound.

It is important to note that ultrasonic frequencies do not travel through walls, so at least one Repeller must be placed in each infested room.

Ultrasonic repellers are not completely effective on their own. For maximum control they should be incorporated into an integrated pest management strategy comprising mechanical traps with food deprivation, sanitation and the closure of access routes. 


Mousetraps are an effective method of non-toxic and humane mouse control. There are 3 types of mouse traps commonly used for rodent control: Snap Traps, Catch Alive Traps, and Electronic Traps.

The following table gives an overview of the different SWISSINNO mousetraps:

A SWISSINNO mousetrap provides a quick and easy solution to a rodent control problem and it can be used many times over. A big advantage of using a mousetrap is that it retains the animal’s carcass so that the ‘trapper’ can dispose of it safely. Death by poison is never instantaneous so the animal may leave the scene and die out of sight in an inaccessible place like behind the skirting boards or under the floor boards where it will decompose emitting noxious odours and attracting flies, maggots and other insects into the home.

Mouse trapping: How to go about it:

  • Before setting out traps, clean up the area removing all tracks, faeces and urine. This will disturb and disorientate the mice and make them less suspicious of the traps. It also helps to see were latest rodent activities took place.
  • Remove all food and food sources. The hungrier the mice, the more readily they will accept the traps.
  • Mice learn quickly from trap failures.  A bad trap often does not make a complete catch but injures the animal and causes it to suffer and to become trap-shy.  Only high-quality traps like SWISSINNO mousetraps are effective and suitable for animal welfare. 
  • Always check traps for proper function before use, especially for sensitive triggering and good spring tension. Don´t use traps that don’t set correctly or that fail to snap shut properly.
  • Wear gloves during trapping. That’s not because of the smell of humans. Rodents in and around buildings are not shy about humans´ smell. The use of gloves is recommended for hygienic reasons as rodents, dead or alive, can transmit serious diseases via contact with their fur or body fluids.
  • Good trap placement is the key to successful trapping. Set traps in areas of high rodent activity. Traps should be placed in the runways of the rodents. Mouse droppings and smear marks are good indicators. Traps are set best along walls or in corners and not in the middle of the room.

    Optimal placement of the trap into a runway
  • Traps must sit firmly on the ground. Rodents shy off from traps that move or make sounds when touched. A secure position is also important for a clean strike and preventing failures.

    Trap set on a board to give a good standing and fixed with a wire so it can't be dragged away.
  • It is better to set out more than a single trap, even if you think, that there is only one mouse present. If there are more mice, several traps should be set out anyways. The distance between traps should be no more than 5m.
  • If pets have access to the trapping sites, or when setting traps outdoors, the traps should be covered or placed in trap tunnels. This keeps non-targeted animals  off the traps.  The Mousetrap “No See-No-Touch” with its integrated tunnel is safe and does not need additional cover. The Mousetrap PRO SuperCat with patented trigger system is selective and helps avoid killing non targeted animals.

    Traps set in a box to keep away non targeted animals and prevent trap loss.
  • Traps should be secured with a wire or cord to prevent loss. Caught mice can carry away the trap before they die. Outdoors predators often carry away caught rodents together with trap.
  • Set traps must be checked daily. Carcasses should be disposed of before they become a hygiene problem. In case of an incomplete catch foul catch (not lethal) the animal must be dispatched. Traps that have been ignored should be moved to a different pposition. If needed, traps should be rebaited respectively reset. Non-targeted animals should be released, provided that they are not injured.
  • If traps are found tripped but empty. (failed catches), it is recommended to switch to a different model of trap. The best trap for mice is the Mousetrap PRO SuperCat. With this model, no failures or imperfect catches occur.
  • Most SWISSINNO Mousetraps are baited with peanut butter. Replacement bait syringes are available separately. The range of attractive of this bait is not more than 2 meters and rodents will not be lured from further away or from the exterior of the building.
  • “Prebait”: If a trap is being ignored, placing a small amount of bait, no more than pea-size, in front of the trap may help.

    Mouse trap with small portion of peanut butter as “prebait”
  • If the peanut butter baited traps do not work, try a chocolate spread like Nutella instead. Nutella is an excellent alternative.
  • The smell of a dead mouse from previous catch does not repel mice. In fact, used traps are more attractive to them. If traps need to be cleaned, use warm water only with a soft brush and not detergent.
  • Catch alive traps should be checked every 4 hours. Otherwise the stress can kill the captive rodent. Caught live mice must be released at least 2 km away, otherwise they will find their way back. 
  • If there is evidence of the presence of species which are protected by law, it is recommended to contact local authorities before starting control measures. Already active measures would have to be stopped immediately until approved. Even the use of “catch alive” traps without authorisation represents an infringement.

Poison bait

It is better to fight mice with traps. Swissinno advises against the use of poison bait for several reasons:

  • Toxic baits endanger the environment, children, pets, domestic, farm and other non-target animals.
  • Poison baits cause slow and painful death of rodents. After consuming such bait, it takes several days for the animal to die.
  • When using poison bait indoors, the mice often die in inaccessible places and the dead bodies cannot be disposed of. They decompose and give off strong, unpleasant odours that last for weeks. Later the dried-up carcasses serve for years as food for other pests such as flies, moths, and beetles.

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