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Mice

Small, curious rodents that squeeze through tiny gaps, nest in walls, cupboards and appliances and breed quickly. The introduced house mouse causes most household problems.

Written by PestMan Editorial TeamTechnical review pendingPublished Updated
Species
House mouse (introduced)
Gap size
About 6 mm
Droppings
3–6 mm
Peak indoors
Autumn and winter
Risk level
Moderate

Mouse identification

How to recognise mice

  • Small: body about 6–10 cm plus a similar-length tail.
  • Large ears and small feet relative to a young rat.
  • Droppings: roughly 3–6 mm, rod-shaped with pointed ends, often scattered in large numbers.

Mouse overview

The house mouse (Mus musculus) is an introduced rodent found throughout Australia, from city apartments to rural properties, where it can reach plague numbers in grain-growing regions.

Mice explore constantly and investigate new objects, so they are usually easier to trap than rats. Their small size means they get inside through remarkably small gaps.

Behaviour

  • Active mainly at night, but may be seen during the day in larger infestations.
  • Travel short distances from the nest, often within a few metres.
  • Nibble on many food sources rather than eating a lot in one place.

Habitat

  • Wall cavities, kitchen kickboards, behind appliances and in stored boxes.
  • Sheds, garages, sub-floors and grain or feed stores.

Lifecycle

  • Mice can breed from around six weeks of age, with litters of about 5–8 young.
  • A female can have many litters a year, so numbers can rise quickly.

Food sources

  • Grains, cereals, seeds and pet food.
  • Crumbs and food scraps.
  • They can obtain much of their water from food.

Entry points

  • Gaps of about 6 mm (roughly the width of a pencil).
  • Around pipes under sinks, dishwasher and laundry plumbing.
  • Gaps under doors, weep holes and garage doors.

Infestation signs

  • Small droppings in drawers, pantry shelves and along skirting boards.
  • Chewed food packaging.
  • Scratching in walls at night.
  • A musky smell in enclosed areas.

Health implications

  • Mice can contaminate food and surfaces with bacteria such as Salmonella.
  • Nesting in appliances and gnawing wires can damage property.

Prevention

  • Store food, including pet food, in hard sealed containers.
  • Seal gaps around pipes and doors with steel wool and sealant, or fit door sweeps.
  • Reduce clutter and cardboard storage.
  • Keep garden and shed areas tidy and feed away from the house.

Treatment overview

  • Snap traps placed along walls where droppings are found are effective and avoid poison.
  • Bait should be used only in tamper-resistant stations and strictly according to the label.
  • Exclusion is essential; otherwise new mice replace the ones removed.
Product safety

If you use any pest product, read the label first and follow it exactly — it is a legal requirement in Australia. Keep products away from children, pets and food areas as the label directs.

Questions about mice

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Rats

Introduced rodents that live alongside people, nest in roofs, walls and gardens and gnaw through building materials and wiring. Roof rats are the most common household rat in many Australian cities.

Cockroaches

Fast, flat-bodied insects that hide in warm, damp gaps and come out at night to feed. A few introduced species cause most household problems in Australia.

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Sources & further reading

PestMan provides general information only and does not replace licensed pest-management, medical, veterinary or structural advice. Always read and follow product labels. Read our disclaimer.