How do the fur colours of Mus species vary?

Within the genus Mus, there is significant variation in fur colour among the 38 recognized species.1

A common colour pattern observed in many species consists of gray to brown upperparts, white underparts, white feet, and a tail that is dark above and white below. However, variations of this pattern are widespread:1

• Upperparts: Can range from buff, bluish gray, and reddish brown to chocolate brown or blackish gray.1
• Underparts: Range from white to various shades of gray, occasionally tinged with silver or buff.1
• Feet and Tail: The feet may be white or match the colour of the upperparts, while the tail can be bicoloured or uniformly dark gray to dark brown.1

Specific populations, such as the house mouse (Mus musculus), exhibit further diversity. Native populations typically feature tawny-brown upperparts and white bellies, whereas introduced feral populations often have dark, grayish brown upperparts that pale to gray on the sides. Furthermore, domesticated laboratory strains of the house mouse can be white (true albinos), black, blond, or patterned with black and white.2