Common mice species

Field and house mice are among the most frequently encountered rodent species in Australia, each with distinct traits. Field mice typically have sandy or reddish brown coats with lighter undersides and are commonly found outdoors in rural or semi rural areas, especially in sheds or near stored crops. House mice, on the other hand, are smaller, grey brown in colour, and prefer to live inside or around human dwellings. Unlike field mice, which rarely venture indoors, house mice thrive in homes and commercial buildings throughout the year. Understanding the key differences between these two species helps identify infestations early and choose the right treatment strategy.

There are many different types of mice present in Australia.

Two species considered to be a major pest in this country are the Field Mouse and the common House Mouse.

• Field mice
• House mice

Field Mouse

(Apodemus sylvaticus)

Field mouse rarely venture into inhabited buildings but in the winter months, they will go into outhouses and sheds where fruit and vegetables are stored.

Field mouse are a big threat to businesses operating in farming and agriculture but is not prevalent in Australia.

Appearance of the Field Mouse

• Size: adult head and body 80 – 100mm in length; Tail 70 – 90mm.
• Weight: Male can weigh 25g, and the female 20g.
• Sandy / orange brown fur on the head and back.
• Yellowish fur on the flanks and white on the belly.
• There is usually a small streak of yellow on the chest.

Life cycle of the Field Mouse

• Their lifespan averages two to three months, but they can survive as much as 20 months in the wild, or two or more years in captivity.
• Breeding seasons are October/November to March/April and gestation lasts approximately 25 days. They grow their first fur after six days; their eyes open after 16; and they are weaned at around 18 days old.
• Survival of the young and adults is poor during the first half of the breeding season as adult males can be aggressive towards one another and to the young, who are then driven from the nest.

Habits of the Field Mouse

• They eat a high proportion of the seed crop of trees such as oak, beech, ash, lime, hawthorn and sycamore. Numbers can reach plague proportions in the grain belt areas.
• Small snails and insects are particularly important sources of food in late spring and early summer when seeds are less available.
• They also eat apples and will attack newly planted legume seeds.

House Mouse

(Mus domesticus)

House mouse are active all year round, which means you could find them invading your home or business at any time.

Appearance of the House Mouse

• Size: 70 – 95mm in length, with a tail around the same length.
• Weight: 12 – 30g.
• Their relatively small feet & head and large eyes & ears distinguish them from a young brown rat (Rattus norvegicus).

Life cycle of the House Mouse

• 4 – 16 young per litter; 7 – 8 litters a year.
• Gestation period of about 3 weeks.
• 8 – 12 weeks from birth to sexual maturity.

Habits of the House Mouse

• Usually ground living and burrowing, but often climbs.
• Preferred food is cereals.
• Will eat around 3g of food a day and can survive without any additional water. They will drink up to 3ml a day if their diet is particularly dry.

Why mouse activity increases in Australian properties

Mice activity often increases during seasonal changes, particularly when outdoor food sources decline or temperatures shift. In rural regions, grain harvesting periods can drive mice toward storage facilities and sheds. In suburban areas, easily accessible food waste and cluttered storage areas provide ideal nesting conditions.

Even small structural gaps around doors, vents and plumbing can allow mice to enter. Once inside, concealed areas such as wall cavities and roof voids provide shelter that supports breeding and ongoing activity.

Risks associated with mouse infestations

Mice can contaminate food products, damage packaging and insulation, and gnaw on electrical wiring. In commercial environments such as hospitality venues, warehouses and food processing sites, mouse activity can affect hygiene standards and stock integrity.

Early identification reduces the risk of structural damage and operational disruption.

When to arrange professional mouse control

You should arrange professional mouse control if you notice droppings, scratching sounds at night, gnaw marks, nesting materials or unusual odours. Mice reproduce quickly, so delays can allow populations to increase.

Rentokil provides tailored mouse control services for Australian homes, farms and businesses. Our technicians assess activity levels, identify access points and apply targeted treatments suited to the property and environment.