Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)
Listed as Least Concern in view of its tolerance of some degree of habitat modification and since it persists quite well in secondary degraded forest. However, in eastern Nigeria, there is some hunting pressure which if continues unabated may place this species in a higher category of threat.
This species is found in western Equatorial Africa, with a very patchy and localised distribution within the lowland rainforest block between the Niger River and the Sanaga River in Nigeria and Cameroon.
Confined to areas of very dense, low undergrowth with abundant lianas and vines within the understorey of primary, secondary, and coastal rainforest. This species particularly favours the growth that springs up in clearings, trees falls, and along forest edges. Wherever it is already established, small-scale clearances, selective tree-felling, and road-making probably favour this species. In such areas it is likely to become abundant in thickets and patches of dense secondary growth. It feeds mainly on caterpillars (which are found by smell), and also on beetles and fruits. This species is able to produce two young in a year.
Major threats are habitat destruction from forestry and clearance for cultivation, as well as some hunting for meat in Nigeria. This species will not be affected by low-level habitat disturbance, since it is able to inhabit secondary forests as long as dense undergrowth remains and inter-tree distance are not too great. However, broader clearances (e.g. those made for plantations, clear-felling, and agriculture) are likely to eliminate it because of its weak capacity to disperse.
This species is listed as Class B under the African Convention, and under Appendix II of CITES. It is known to occur in Cross River National Park (Nigeria) and Korup National Park (Cameroon). It probably occurs in a few others in the area, although its presence is not confirmed. Further surveys are needed to determine its true conservation status.