Mouse facts

Mice are hardy little creatures, so if there's a mouse in your house you may want to know a bit more about what makes it tick.

How do I identify a mouse?

Mice measure about eight centimetres in length (excluding the tail) and have an average weight of 12–22 grams. Their fur is brown/grey, with slightly lighter shading on their underside.

Where do mice live?

House mice are mainly found in close contact with human beings.

Outside, they can live:

  • Under wood piles or lumber that is not in frequent use
  • Under bushes and vines and in tall thick grass
  • In appliances and old furniture that has been left outside and is not being used
  • In and around rubbish that has been left out
  • In holes or gaps under buildings

Inside they will happily make their homes:

  • Inside the insulation of walls or ceilings
  • In or behind cupboards, counters and bathtubs
  • Near the boiler
  • In basements or attics where things like cardboard and cloth are stored

What do mice eat?

Rather than their stereotype of being cheese lovers, the foods most favoured by the house mouse are cereals, biscuits and chocolate. When in the house, mice will eat almost anything not sealed in an air-tight container.

House mice largely get the moisture they need from their food so do not need to seek out water.

What attracts mice?

In a word: food. Mice are masters at finding any scrap of food in and around your home, but their favourites are:

  • Uncollected rubbish and litter
  • Food for pets and birds that has been left out and not eaten
  • Fruits and berries that have fallen to the ground
  • Untended compost piles
  • Discarded food

How do I know if I have a mouse problem?

You will know that you've got a mouse problem when you see, hear or smell:

  • Droppings (typically around five millimetres long) found near food sources
  • Scratching noises
  • Evidence of gnawing
  • Burrows or nests
  • You may also notice a strong musky odour

Are mice harmful?

If they enter into the home wild mice may carry parasites and diseases that are harmful to humans and animals, including:

  • Salmonella
  • Listeria

Another significant problem is the structural damage mice can cause from their gnawing and burrowing activities. This ranges from minor holes in walls/doors/furniture/cupboards to structural collapse, flooding, electrical faults and fire (due to gnawing through cables).

Things you might not know about mice

  • Mice are not incontinent, but they do scent-mark pathways and territories.
  • A mouse's teeth grow continuously, and are worn down by gnawing on hard surfaces and by working them against each other (known as bruxing).
  • Mice are excellent climbers and can swim if necessary, although they tend to avoid water.
  • Mice are crepuscular, meaning that they are most active at twilight (dawn and dusk), although they can sometimes be seen during the day.
  • They have poor eyesight and are colour blind, but have acute hearing and a good sense of smell and taste.
  • Mice are capable of reproducing from four weeks old and have an average litter size of 9-12 young.
  • The average life expectancy of a house mouse is 9-12 months.

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