How do feral house mice differ in colour from native house mice?

The house mouse (Mus musculus) exhibits distinct colour variations between its native and introduced feral populations:

• Native populations: These mice typically feature tawny-brown upperparts with white bellies and possess shorter, bicoloured tails.1
• Introduced feral populations: These mice are characterized by dark, grayish-brown upperparts that pale to gray on the sides. Their underparts are similar in colour to their sides, sometimes with a buff tinge, and they have a uniformly dark gray tail.1

These differences in appearance are distinct from domesticated laboratory strains, which may be white (true albinos), black, blond, or patterned with black and white.1