The fore-feet are small with five digits, one without a claw, and sparse white hairs; the hind-feet are also small, have five digits with claws, and bear sparse white hairs.

[3] Very little is known about the ecology and behaviour of the Mount Oku hylomyscus as only four individuals have been collected.

It lives in montane forest and the length of its tail makes it likely that it has a climbing life-style.

[3] H. grandis has a very restricted range, only four specimens having been gathered from a single location at 2,100 m (6,900 ft) above sea level on the slopes of Mount Oku in Cameroon.

[1] Its total area of occurrence is approximately 470 km2 (180 sq mi) and little of the natural forest in which it lives remains, as trees are being felled to make way for agriculture, and to provide timber for construction and firewood.