New Holland mice are little rodents that have a grey-brown fur with a dusky-brown tail, which is darker on the dorsal side. These mice look very similar to the Common house mouse, which was introduced to the area by European settlers. However, New Holland mice have slightly larger ears and eyes and they lack a distinctive 'mousy' odor.
New Holland mice are found only in south east Australia, within the states of New South Wales, Queensland, Victoria, and Tasmania. They inhabit woodlands, forests with a heathland understorey and vegetated sand dunes, and open heathlands.
New Holland mice are social animals. They live in burrows that are carved out by colonies of mice in softer sands. These mice are active at night and spend a majority of their time foraging.
These omnivorous mice feed mainly on seeds above ground. Although seeds are the most prominent component of New Holland mice diet, they also consume leaves, fungi and small invertebrates.
Little is known about the mating habits of New Holland mice. Young are born between the months of August and January, and their breeding patterns are based on the amount of food obtained, which depends on rainfall. Births occur in the mother’s nest during the day. Litters normally consist of 1-6 pups. During their first year of reproduction, females will normally produce only one litter a season, but during their second year they can produce up to three or four litters. Females nurse their young for 3-4 weeks. Males in this species reach reproductive maturity at around twenty weeks of age, females will mature at around thirteen weeks of age.
Main threats to New Holland mice are inappropriate fire regimes, habitat loss and fragmentation, climate change and habitat degradation due to weeds, livestock and non-native herbivores. The most severe and pressing danger comes directly from the threat of predators in the environment. Predation is brought upon by the natural predators in the environment. Such predators include the Red Fox, cats, and dogs. In addition to the increase of predators, an increase in competition for resources in the environment has also been noted a contributor to their decline. The competition is most frequently encountered between other species of rodents in the same habitat.
According to the IUCN Red List, the total population size of New Holland mice is around 8,000 mature individuals. This species’ numbers are decreasing and it is currently classified as Vulnerable (VU) on the IUCN Red List.