The thinly haired tail is about the same color, though in some animals it is entirely black. Although Hybomys resembles Arvicanthis externally in such features as the dark dorsal stripe, it differs from the latter genus by its more slender form and almost naked tail. The soles of the feet have five well-developed tubercles and a rudimentary sixth, whereas the palms have six tubercles, all well developed. The thumb is small and has a blunt nail. The hind foot is narrow.
Females have two or three pairs of mammae.
These mice inhabit forests, thick brush, and the edges of cultivated areas. Individuals spent the night, and resting periods during the day, in burrows, within which they built nests of twigs. Each animal used several burrows, but males, at least, spent most inactive time in one favored lair. Hybomys also may shelter in rotting logs, piles of twigs, or termite mounds. Home ranges of males did not overlap, and intruders were chased and viciously bitten.