Praomys mutoni has darker dorsal fur than related species and a dark tail. Specimens examined in its description came from wet areas along streams in Masako Forest Reserve, Democratic Republic of the Congo.
In the species description, the underside is whitish grey, the back is darker than in related species, and the dark tail is sparsely haired.
The examined animals were found in especially wet places, including beside small streams and rivers. The source gives no detailed record of diet or activity time.
An extinction-risk assessment has not been added yet.