Cercopithecus mitis is a large, arboreal omnivore. Lives in many forest types, including lowland and montane tropical moist forest, riverine, gallery forest, delta forest, mangrove forest and bamboo forest (Butynski 1990; Lawes et al. 1990, 2013; de Jong and Butynski 2009; Butynski and de Jong in press). Also found in sand forest, secondary forest, logged forest and thickets. Despite its eurytopic ecology, grassland, bushland and open woodland act as distributional barrier which (partly) explains its current fragmented geographical range (de Jong and Butynski in prep). Group size is typically 10–25 individuals (range 3–65 individuals; Butynski 1990, Lawes 1992, Lawes et al. 2013). Cercopithecus mitis is a poor coloniser in response to forest fragmentation. Rarely occupies small (<50 ha) forest patches (Lawes et al. 2000, Chapman et al. 2003). Cercopithecus mitis has a flexible, broad, diet but primarily eats ripe fruits and invertebrates. Also forages on leaves, seeds, flowers, stems, galls, bark, gum, fungi and small vertebrates (Butynski 1982, 1990; Lawes et al. 2013).

Photographic maps of many of the subspecies of Cercopithecus mitis can be found at http://www.wildsolutions.nl/photography/

Cercopithecus mitis is endemic to Africa and has an extensive geographic range. There is an isolated population (C. m. mitis) that is endemic to Angola. Otherwise, this species ranges from central Democratic Republic of Congo (DRC) east to the Indian Ocean. It is present from southwest Ethiopia in the north to east South Africa in the south (Colyn and Verheyen 1987, Lawes 1990, Colyn 1991, Gautier-Hion et al. 1999, Butynski 2002a,b, Kingdon 2013, Lawes et al. 2013). Altitude from sea level to 3,800 m asl (Rwenzori Mountains, Uganda).

There are 17 subspecies recognised:

Cercopithecus mitis albotorquatus (Pousargues’s Monkey). Endemic to Kenya and south Somalia. Present along the Kenya coast in Boni National Reserve, Dodori National Reserve, Kipini Conservancy, Lamu Archipelago, Witu Forest Reserve and inland to Tana River Primate National Reserve, Meru National Park, and Kora National Park. In the coastal forests of south Somalia, perhaps as far north as Kismayo (T. Butynski and Y. de Jong pers. obs. 2016).

Cercopithecus mitis kolbi (Kolb’s Monkey). Endemic to the Central Highlands of Kenya east of the Rift Valley (including Nairobi, Ngong Hills, Aberdares Range, Mount Kenya and Laikipia Plateau). There is no evidence that C. m. kolbi occurs at Marsabit (T. Butynski and Y. de Jong, pers. obs. 2012) as sometimes stated.

Cercopithecus mitis albogularis (Zanzibar Sykes’ Monkey). From Kilifi Creek on the Kenya coast southwards to the Ruvu River, north Tanzania, including Mount Kilimanjaro, Mount Meru and Zanzibar Island. This may be the subspecies present from Kilifi Creek to the Sabaki River, Kenya (de Jong and Butynski 2009, pers. obs. 2009). 

Cercopithecus mitis francescae (Red-eared White-collared Monkey). West of Lake Malawi, from Mount Chombe in north to Mount Ntchisi in south (Ansell and Dowsett 1988). Only known from Mount Waller and the Vipya Plateau, Malawi (Kingdon 2013).

Cercopithecus mitis moloneyi (Moloney’s Monkey). From northeast Zambia west of the Luangwa River, to north-most Malawi, to the Southern Highlands and Lake Rukwa, south Tanzania. (Lawes et al. 2013). There appears to be in a phenotypic cline with C. m. monoides in the Udzungwa Mountains (T. Butynski pers. obs. 2009). 

Cercopithecus mitis erythrarchus (Stairs’s Monkey or Samango Monkey). From the Mlanje Plateau in southern Malawi, south to Zimbabwe, much of Mozambique (although the coastal limits are uncertain), to Limpopo Province and northern KwaZulu-Natal in South Africa. Not south of Umfolozi River (Lawes et al. 2013).

Cercopithecus mitis labiatus (Samango Monkey). Endemic to the highlands of east South Africa; Limpopo Province, Mpumalanga, KwaZulu-Natal and Eastern Cape (Lawes et al. 2013).

Cercopithecus mitis heymansi (Lomami River Monkey). Endemic to DRC between Lualaba River and Lomami River (Kingdon 2013, Lawes et al. 2013).

Cercopithecus mitis opisthostictus (Rump-spotted Monkey). From Katanga Province (= Shaba) in DRC, north to ca. 6°N on the left bank of the Lualaba River to west and south-east shores of Lake Tanganyika. In northwest Zambia west of the Luangwa River (Kingdon 2013, Lawes et al. 2013).

Cercopithecus mitis mitis (Angola Pluto Monkey). Endemic to western Angola (Kingdon 2013, Lawes et al. 2013).

Cercopithecus mitis boutourlinii (Boutourlini’s Blue Monkey). Southwest Ethiopia from Lake Tana southwards along the west side of the Ethiopian Rift, but does not reach Lake Turkana (Kingdon 2013). 

Cercopithecus mitis stuhlmanni (Stuhlmann’s Blue Monkey). Widespread. In DRC from the Uele River and Congo River, east of the Itimbiri River to the Ituri Forest and Semliki Forest, Uganda, southwards to about 6°S and east of the Lualaba River. In south South Sudan, north Uganda (Imatong Mountains, Kidepo Valley), and southwest Kenya west of the Eastern Rift Valley, including Mount Elgon, Kakamega Forest, Mau Forest Complex and the Cherangani Hills (Kingdon 2013, Lawes et al. 2013, Butynski and de Jong 2014, de Jong & Butynski 2014).

Cercopithecus mitis schoutedeni (Schouteden’s Silver Monkey). Endemic to eastern DRC on the islands of Idjwi and Shushu in Lake Kivu, and west Virunga Mountains southwest to Bobandana (Kingdon 2013, Lawes et al. 2013).

Cercopithecus mitis doggetti (Doggett’s Silver Monkey). Highlands of eastern DRC, north Burundi, northwest Tanzania, through Rwanda and southwest Uganda (Kingdon 2013, Lawes et al. 2013, T. Butynski pers. obs. 2016).

Cercopithecus mitis kandti (Golden Monkey). Eastern DRC near L. Kivu, Virunga Mountains of Rwanda and Uganda, and Nyungwe National Park, southwest Rwanda (Lawes et al. 2013).

Cercopithecus mitis zammaranoi (Zammarano’s Monkey). Endemic to south Somalia along the Jubba River and Webi-Shebeli River (Gippoliti 2006).

Cercopithecus mitis monoides (Tanzania Sykes’ Monkey). Coastal Tanzania (including Selous Game Reserve and Kichi Hills), west to foot of the Udzungwa Mountains, south into Newala District and northeast Mozambique. On Mafia Island, Tanzania (Kingdon 2013, Lawes et al. 2013).

Listed on Appendix II of CITES and on Class B of the African Convention on the Conservation of Nature and Natural Resources. Cercopithecus mitis is present in many protected areas across its range. There is an urgent need to assess the current status of C. m. zammaranoi and C. m. schoutedeni.