{{Short description|Species of Old World monkey}} {{redirect|Blue Monkey|the 1987 film|Blue Monkey (film){{!}}''Blue Monkey'' (film)|the microbrewery|Blue Monkey Brewery}} {{Use dmy dates|date=January 2026}} {{Speciesbox | name = Blue monkey | image = Blue monkey (Cercopithecus mitis stuhlmanni).jpg | image_caption = ''C. m. stuhlmanni''<br />Kakamega Forest, Kenya | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=Butynski, T.M. |author2=de Jong, Y.A. |date=2019 |title=''Cercopithecus mitis'' |volume=2019 |article-number=e.T4221A196007901 |doi=10.2305/IUCN.UK.2019-3.RLTS.T4221A196007901.en |access-date=19 November 2021}}</ref> | genus = Cercopithecus | species = mitis | authority = Wolf, 1822 | range_map = Cercopithecus mitis distribution map, crop.png | range_map_caption = {{legend0|#e60000| Range (note: includes ranges of closely related Sykes', silver, and golden monkeys)}} | subdivision_ranks = Subspecies | subdivision = 6, see text }}
The '''blue monkey'''<ref name="MSW3">{{MSW3 Groves|pages=157|id=12100475}}</ref> or '''diademed monkey''' ('''''Cercopithecus mitis''''') is a species of Old World monkey<ref name="Forster">{{cite journal |last1=Förster |first1=Steffen |last2=Cords |first2=Marina |year=2005 |title=Socialization of infant blue monkeys (''Cercopithecus mitis stuhlmanni''): Allomaternal interactions and sex differences |url=https://academiccommons.columbia.edu/doi/10.7916/D8ZC8DMK/download |journal=Behaviour |volume=142 |issue=7 |pages=869–896 |doi=10.1163/1568539055010138 |s2cid=85928885}}</ref><ref>Hutchins, M., Kleiman, G.D., Geist, V., McDada, M.C. 2004. Grzimek's Animal Life Encyclopedia. 14:2. Gale Group.</ref> native to Central and East Africa, ranging from the upper Congo River basin east to the East African Rift and south to northern Angola and Zambia and populations further south down to South Africa. The taxonomy of this species has been disputed and Sykes' monkey, the silver monkey and the golden monkey are often regarded as subspecies.<ref name=MSW3/>
==Subspecies== Several subspecies are recognised:<ref name=MSW3/> * ''Cercopithecus mitis boutourlinii'' – Boutourlini's blue monkey, found in Western Ethiopia. Identified and named by Leopoldo Traversi.<ref name=":1">{{Cite web |title=Leopoldo Traversi {{!}} Il Corno d'Africa |url=https://www.ilcornodafrica.it/leopoldo-traversi/ |access-date=2025-12-08 |language=it-IT}}</ref> * ''Cercopithecus mitis elgonis'' – Elgon blue monkey * ''Cercopithecus mitis heymansi'' – Lomami River blue monkey, found in Congo * ''Cercopithecus mitis kolbi'' – Kolb's monkey, found in Kenya * ''Cercopithecus mitis labiatus'' – Samango monkey, found in South Africa, Eswatini and southern Mozambique<ref>{{cite book |author1=Chris Stuart |url=https://books.google.com/books?id=CkRlEQAAQBAJ&pg=PT311 |title=Stuarts Field Guide to Mammals of Southern Africa Including Angola, Zambia & Malawi |author2=Mathilde Stuart |publisher=Penguin Random House South Africa |year=2025 |isbn=9781779890085 |page=311}}</ref> * ''Cercopithecus mitis mitis'' – Pluto monkey, found in Angola * ''Cercopithecus mitis moloneyi'' – Moloney's blue monkey<ref>{{cite iucn |author=Kingdon, J. |year=2008 |title=''Cercopithecus mitis'' ssp. ''moloneyi'' |volume=2008 |article-number=e.T136864A4347598 |doi=10.2305/IUCN.UK.2008.RLTS.T136864A4347598.en |access-date=10 January 2026}}</ref> * ''Cercopithecus mitis opitsthosticus'' * ''Cercopithecus mitis schoutedeni'' – Schouteden's blue monkey, found in Congo * ''Cercopithecus mitis stuhlmanni'' – Stuhlmann's blue monkey At times, some of these have been regarded as full species, and additional subspecies have been considered valid, while others are not recognized by all authorities.
<gallery mode="packed" heights="130px"> Blue Monkey, Lake Manyara.jpg|Lake Manyara National Park, Tanzania BlueMonkey.jpg|Lake Manyara National Park, Tanzania Blue monkey (Cercopithecus mitis stuhlmanni) pair.jpg|''C. m. stuhlmanni''<br />Kakamega Forest, Kenya Blue monkey (Cercopithecus mitis stuhlmanni) walking.jpg|''C. m. stuhlmanni''<br />Kakamega Forest, Kenya </gallery>
==Description==
Like other mammals with the name "blue" (blue tick hound, blue wildebeest), the blue monkey often has a slaty-grey cast that can look blue to observers. It is mainly olive or grey apart from the face (which is dark with a pale or yellowish patch on the forehead – the "diadem" from which the species derives its common name), the blackish cap, feet, and front legs, and the mantle, which is brown, olive, or grey depending on the subspecies. Typical sizes range from {{cvt|50|to|65|cm}} in length, (not including the tail, which is almost as long as the rest of the animal), with females weighing a little over {{cvt|4|kg}} and males up to {{cvt|8|kg}}.<ref>{{Cite web |title=Blue Monkey in Africa |url=https://www.africa-uganda-business-travel-guide.com/blue-monkey-in-africa.html |access-date=30 May 2020 |website=africa-uganda-business-travel-guide.com}}</ref>
==Ecology== ===Habitat=== The blue monkey is found in evergreen forests and montane bamboo forests, and lives largely in the forest canopy, coming to the ground infrequently. It is very dependent on humid, shady areas with plenty of water. It eats mainly fruit and leaves, but will take some slower-moving invertebrates. It prefers to live in tall trees, which provide both food and shelter, and is, therefore, like almost all guenons, suffering from the loss of its natural habitat. Where pine plantations replace natural forest, the monkey may be treated as a threat by foresters, since it sometimes strips bark from exotic trees in a search for food or moisture.<ref name="MonkeyWorlds">{{Cite web |last=Atwood |first=Adam |date=23 February 2024 |title=Blue Monkey |website=MonkeyWorlds |url= https://monkeyworlds.com/blue-monkey/ |access-date=25 February 2026}}</ref> It is also hunted for bushmeat and as payback for crop-raiding.<ref>{{Cite journal |last=Basabose |first=Augustin |date=2024 |title=Confirmed Presence of a Small, Isolated Population of Cercopithecus mitis on Idjwi Island, Democratic Republic of Congo |url=http://static1.1.sqspcdn.com/static/f/1200343/28660132/1722706155197/AP+Vol+18+1+Basabose+et+al.pdf?token=3hCGgm5Cx7kd5mPwcvuA4pur%2Fio%3D |journal=African Primates |volume=18 |issue=1}}</ref>
===Diet=== Blue monkeys primarily eat fruits, including figs. They also eat insects, leaves, twigs, and flowers.<ref name=MonkeyWorlds /> "They are primarily frugivores, with 50% of their diet consisting of fruit, with leaves or insects being the main source of protein, with the rest of the diet being made up of seeds, flowers and fungi. [....] They eat a variety of plants but concentrate on a few species, which means their population density is generally dependent on plant species richness and diversity."<ref name=SANBI>{{cite web |title=The Samango monkey working group |url= https://www.pretoriazoo.org/research/the-samango-monkey-working-group/ |publisher=SANBI and National Zoological Gardens |access-date=25 February 2026}}</ref> Rarely, they eat vertebrates,<ref name=SANBI /> such as lizards, birds, and small mammals including bushbabies.<ref name=Rademacher>{{cite web |first=Lina |last=Rademacher |date=2024 |title=Blue monkey |publisher=New England Primate Conservancy |url= https://neprimateconservancy.org/blue-monkey/ |access-date=25 February 2026}}</ref>
==Behavior== [[File:Samango monkey (Cercopithecus mitis erythrarchus) Mount Sheba.jpg|thumb|''Cercopithecus mitis labiatus'' (Samango monkey) at Mount Sheba, South Africa]] ''Cercopithecus mitis'' joins with the ''C. ascanius'' (red-tailed monkey) for extra protection.<ref name=Strawder>{{cite web |title=''Cercopithecus mitis'' |first=Nicole |last=Strawder |date=2001 |work=Animal Diversity Web |url= https://animaldiversity.org/accounts/Cercopithecus_mitis/ |access-date=25 February 2026}}</ref> Its interactions with red-tailed monkeys include interspecies grooming.<ref>{{cite journal |author=Lee |first=Z.H. |last2=Ang |first2=A. |last3=Ruppert |first3=N. |date=26 August 2021 |title=First record of interspecies grooming between Raffles' Banded Langur and Long-tailed Macaque |url= https://threatenedtaxa.org/index.php/JoTT/article/view/7510/7884 |journal=Journal of Threatened Taxa |volume=13 |issue=9 |pages=19246–19253 |doi= 10.11609/jott.7510.13.9.19246-19253 |access-date=5 September 2021 |doi-access=free}}</ref> Their social system is mainly female because the males leave once they are mature.<ref name=MonkeyWorlds /> Males have little to no interaction with the young. ''C. mitis'' is very territorial, so young males must leave. They may challenge the dominant male of another family. If they defeat the dominant male, they take over leadership of that family, and this offers a place to live, socialization, and food supplies.<ref name=MonkeyWorlds />
===Social structure=== <!-- inline references added. Cords 2001 was replaced with Cords 2002 ref. --> The blue monkeys live in female-philopatric social systems where females stay in their natal groups, while males disperse once they reach adulthood.<ref name=Forster/> As a result, blue monkey groups usually consist of one male with several females and infants, giving rise to matrilinear societies.<ref name=Forster/><ref name=Cords86/><ref name=Cords/> Occasionally, solitary males are observed, which are probably transient, having left their natal group in search of a new group.<ref name="MonkeyWorlds"/><ref>{{Cite web |title=Blue monkey |url=https://www.projectnoah.org/spottings/7087474 |access-date=25 May 2020 |website=Project Noah}}</ref><ref>{{Cite web |title=Blue Monkey |url=https://www.reachafricanwildlife.com/blue-monkey/ |access-date=25 May 2020 |website=Get to African Wildlife safaris |language=en-US}}</ref>
====Social relationships==== In these female-bonded societies, only 5–15% of monkeys' activity budget is occupied by social interactions and the most common social interactions within a group are grooming and playing.<ref name="Cords86">{{cite journal |last=Cords |first=Marina |year=1986 |title=Interspecific and Intraspecific Variation in Diet of Two Forest Guenons, ''Cercopithecus ascanius'' and ''C. mitis'' |journal=Journal of Animal Ecology |volume=55 |issue=3 |pages=811–827 |bibcode=1986JAnEc..55..811C |doi=10.2307/4418 |jstor=4418}}</ref><ref name="Cords">{{cite journal |last=Cords |first=Marina |year=2002 |title=Friendship among adult female blue monkeys (''Cercopithecus mitis'') |journal=Behaviour |volume=139 |issue=2–3 |pages=291–314 |citeseerx=10.1.1.505.6980 |doi=10.1163/156853902760102681 |bibcode=2002Behav.139..291C |s2cid=145357186}}</ref><ref name="Gathua">Gathua JM. 2000. Intraspecific variation in foraging patterns of redtail monkeys (Cercopithecus ascanius) in the Kakamega Forest, Kenya. Dissertation Abstracts International 60-12:A,4497. Columbia University.</ref><ref name="Payne">{{cite journal |last1=Payne |first1=H.F.P. |last2=Lawes |first2=M.J. |last3=Henzi |first3=S.P. |year=2003 |title=Fatal Attack on an Adult Female ''Cercopithecus mitis erythrarchus'': Implications for Female Dispersal in Female-Bonded Societies |journal=International Journal of Primatology |volume=24 |issue=6 |pages=1245–1250 |doi=10.1023/b:ijop.0000005990.39403.96 |s2cid=24628028}}</ref><ref name="Pazol">{{cite journal |last1=Pazol |first1=Karen |last2=Cords |first2=Marina |year=2005 |title=Seasonal variation in feeding behavior, competition and female social relationships in a forest dwelling guenon, the blue monkey (''Cercopithecus mitis stuhlmanni''), in the Kakamega Forest, Kenya |journal=Behavioral Ecology and Sociobiology |volume=58 |issue=6 |pages=566–577 |bibcode=2005BEcoS..58..566P |doi=10.1007/s00265-005-0953-3 |s2cid=25637141}}</ref> Relationships between group members vary: infants interact most frequently with their peers and adult or juvenile females<ref name=Forster/> and are rarely seen near adult males.<ref name="MonkeyWorlds"/><ref name=Forster/>
Alloparenting is common among blue monkeys. The most common infant handlers are juvenile females, and usually one infant is carried by a number of alloparents. One hypothesis is that this allows the infant to learn to socialise at an early stage in life.<ref name=Forster/>
Interesting female-female relationships exist among blue monkeys. This relationship is believed to be shaped by their feeding ecology, which, in turn, is shaped by between-group and within-group competition.<ref name=Pazol/> Blue monkey females exhibit strong, aggressive competition between groups<ref name=Cords86/><ref name=Cords/><ref name=Payne/> and between other species because of their territorial character,<ref name=Cords/><ref name=Payne/> but milder though more frequent competition within groups.<ref name=Cords/> Though earlier beliefs were that blue monkeys are not territorial, more current extended research<ref name=Payne/> shows that earlier researchers misinterpreted the results because social interactions overall are infrequent. Moreover, overall agonism rates in blue monkeys are very low.<ref name=Cords/><ref name=Pazol/> Within-group conflicts are mild and infrequent because females distance themselves from one another and feed at different sites to avoid competition.<ref name=Cords/><ref name=Pazol/> Although blue monkeys were believed to be egalitarian, current extended research confirms that linear dominance hierarchy occurs in female blue monkeys,<ref name=Cords/><ref name=Payne/> which becomes more apparent when food resources are scarce.<ref name=Cords/>
===Reproduction=== The mating system is polygynous, with a corresponding sexual dimorphism in size, as the males are the substantially larger sex. Females normally give birth every two years, during the onset of the warm, rainy season; gestation is around five months, and the infants are born with fur and with their eyes open. Group sizes range from 10 to 40, containing only a single adult male. It is often found in groups with other species of monkeys such as the red-tailed monkey and various red colobus monkeys.<ref>Ghiglieri, Michael. ''East of the Mountains of the Moon: Chimpanzee Society in the African Rain Forest,'' The Free Press, 1988, pg. 238.</ref>
''C. mitis'' males mate with more than one female, but the females only mate with one male. The female attracts males to copulate with her through body language. They breed throughout the year.<ref name=Strawder /> "The groups can have up to 40 members and the females usually help to care for all of the young, not just their own."<ref name=MonkeyWorlds />
==Predation== Blue monkeys likely fall prey to leopards. "Other potential predators include snakes and birds of prey."<ref name=Strawder />
==References== {{Reflist}}
{{C.Cercopithecinae nav}}
{{Taxonbar|from=Q667252}} {{Authority control}}
blue monkey Category:Mammals of Angola Category:Mammals of Burundi Category:Mammals of the Democratic Republic of the Congo Category:Mammals of Ethiopia Category:Mammals of Kenya Category:Mammals of Malawi Category:Mammals of Mozambique Category:Mammals of Rwanda Category:Mammals of Somalia Category:Mammals of South Africa Category:Mammals of South Sudan Category:Mammals of Eswatini Category:Mammals of Tanzania Category:Mammals of Uganda Category:Mammals of Zambia Category:Mammals of Zimbabwe Category:Mammals of Sudan blue monkey Category:Taxa named by Johann Wolf Category:Arboreal mammals