Body length: 6.5-10cm, Weight: 12-22g. House mice have brown-grey fur, with slightly lighter under-parts. They have large ears, a pointed snout and a long tail.

They are typically found in areas near to human habitation and open fields.

All year round ? does not hibernate.

House mice are nocturnal, with some daytime activity. Wild populations are poor competitors with other rodents, and are often displaced by other species when away from human habituation. They are typically aggressive to each other, and fighting is common, although females have an aggression inhibiting hormone in their urine to prevent attack from other mice. House mice build tunnel systems which may be a short tunnel with just one chamber or a complex network with several exits and chambers. Some of these chambers may contain bedding material. Females produce about 5-10 litters per year, consisting of 4-8 young. The young are independent after 3 weeks.

House mice originated in Asia but have since spread throughout the world. Along with brown rats, they are considered to be the most widespread terrestrial mammal other than humans. Often considered a pest species, they are common nationally.

Common in Leicestershire and Rutland.