Order : RODENTIA
Family : Muridae
Species : Mus musculus or Mus castaneus

Head-Body Length : Up to 9 cm
Tail Length : Up to ~ 9 cm

Mus musculus is one of the most widespread of all rodents, occurring in all continents except Antarctica. Its probable original range on the Eurasia land mass has been extended east, west and south due to its commensal habits and adaptation to urban habitats. It is widespread in Southeast Asia.

This small rodent is nominally nocturnal in habits, but may venture out by day if attracted to a food source.

Its fur is soft and greyish-brown, and slightly paler below. Its tail is dark and approximately the same length or slightly longer than its head-body length.

Five subspecies are recognised. The form which occurs in Europe, from which the name 'House Mouse' derives, is Mus musculus domesticus (illustrated here). The form which occurs in Southeast Asia is the subspecies Mus musculus castaneus; some researchers consider this form to be a separate species i.e. Mus castaneus.

Based on the 2016 assessment by IUCN, most Southeast Asia populations of this rodent should be considered as introduced.

Figs 1 to 3 : Example of Mus musculus domesticus found nesting in a hedgerow at the edge of a small town in southern England; it was attracted to small, fallen berries.

References : M5

Musser, G., Hutterer, R., Kryštufek, B., Yigit, N. & Mitsainas, G. 2021. Mus musculus (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2021.