Editing Mandrillus

{{Short description|Genus of Old World monkeys}}
{{Automatic taxobox
| image = Mandril.jpg
| image_upright = 0.9
| image_caption = A [[mandrill]] in captivity
| taxon = Mandrillus
| authority = [[Ferdinand August Maria Franz von Ritgen|Ritgen]], 1824
| type_species = ''[[Mandrill|Simia sphinx]]''<ref>{{cite journal |last1=Allen |first1=Glover M. |title=A Checklist of African Mammals |journal=Bulletin of the Museum of Comparative Zoölogy at Harvard College |date=1939 |volume=83 |page=157 |url=https://www.biodiversitylibrary.org/page/2782708}}</ref><ref>{{cite journal |last1=Melville |first1=R. V. |title=Opinion 1199. ''Papio'' Erxleben, 1777, and ''Mandrillus'' Ritgen, 1824 (Mammalia, Primates): Designation of Type Species |journal=The Bulletin of Zoological Nomenclature |date=1982 |volume=39 |issue=1 |pages=15–18 |url=https://www.biodiversitylibrary.org/page/12227912}}</ref>
| type_species_authority = [[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]
| subdivision_ranks = [[Species]]
| subdivision = {{linked species list|
Mandrillus sphinx{{!}}M. sphinx|(Linnaeus, 1758)|
Mandrillus leucophaeus{{!}}M. leucophaeus|([[F. Cuvier]], 1807)}}
|synonyms_ref=<ref>{{MSW3 Groves|pages=165|heading=''Mandrillus''|id=12100572}}</ref>
|synonyms={{genus list|
Chaeropithecus|Gray, 1870|
Drill|Reichenbach, 1862|
Maimon|Trouessart, 1904|
Mandril|Voigt, 1831|
Mormon|Wagner, 1839|
Papio|P.L.S. Müller, 1773}}
}}

'''''Mandrillus''''' is a [[genus]] of large [[Old World monkey]]s distributed throughout [[Central Africa|central]] and [[southern Africa]], consisting of two species: ''M. sphinx'' and ''M. leucophaeus'', the [[mandrill]] and [[drill (animal)|drill]], respectively.<ref name="www.itis.gov">{{Cite web|title=ITIS Standard Report Page: Mandrillus|url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=572825#null|website=www.itis.gov|access-date=2020-05-26}}</ref> ''Mandrillus'', originally placed under the genus ''Papio'' as a type of [[baboon]], is closely related to the genus ''[[white-eyelid mangabey|Cercocebus]]''.<ref name="Dixson, Alan F.">{{Cite book|last=Dixson, Alan F.|title=The Mandrill : a Case of Extreme Sexual Selection|isbn=978-1-316-33534-5|location=Cambridge|oclc=941030864}}</ref> They are characterised by their large builds, elongated snouts with furrows on each side, and stub tails. Both species occupy the west central region of Africa and live primarily [[terrestrial animal|on the ground]].<ref>{{Cite web|title=Drill {{!}} primate|url=https://www.britannica.com/animal/drill-primate|website=Encyclopedia Britannica|language=en|access-date=2020-05-18}}</ref><ref>{{Cite web|title=Mandrill {{!}} primate|url=https://www.britannica.com/animal/mandrill|website=Encyclopedia Britannica|language=en|access-date=2020-05-18}}</ref> They are [[frugivore]]s, consuming [[omnivore|both meat and plants]], with a preference for plants.<ref name="Dixson, Alan F." /> ''M. sphinx'' is classified as [[vulnerable species|vulnerable]] and ''M. leucophaeus'' as [[endangered species|endangered]] on the ''[[IUCN Red List]] of [[threatened species|Threatened Species]]''.<ref name="IUCNMandrill"/><ref name="IUCNDrill"/>

== Taxonomy ==
''Mandrillus'' is a genus within the tribe [[Papionini]], which in turn is under the subfamily [[Cercopithecinae]]. This subfamily is classified under the family of [[Old World monkeys]] (Cercopithecidae) within the infraorder [[Simian|Simiiformes]].<ref name="www.itis.gov" /> The Papionini tribe contains six other genera: [[baboon]]s (''Papio''), [[macaque]]s (''Macaca''), [[crested mangabey]]s (''Lophocebus''), [[white-eyelid mangabey]]s (''Cercocebus''), the [[Kipunji|highland mangabey]] (''Rungwecebus'') and ''[[Theropithecus]]''.<ref>{{Cite web|title=ASM Mammal Diversity Database|url=https://mammaldiversity.org/|website=American Society of Mammalogists|access-date=2020-05-26}}</ref><ref>{{Cite journal|last=Seamons|first=G.R.|date=July 2006|title=Mammal Species of the World: A Taxonomic and Geographic Reference (3rd edition)|journal=Reference Reviews|volume=20|issue=5|pages=41–42|doi=10.1108/09504120610673024|issn=0950-4125}}</ref>

Originally, both species were considered part of the ''Papio'' genus, as forest baboons, due to superficial similarities such as size and appearance, particularly in facial features.<ref>{{Cite journal|last1=Strasser|first1=Elizabeth|last2=Delson|first2=Eric|date=1987-01-01|title=Cladistic analysis of cercopithecid relationships|journal=Journal of Human Evolution|language=en|volume=16|issue=1|pages=81–99|doi=10.1016/0047-2484(87)90061-3|bibcode=1987JHumE..16...81S |issn=0047-2484}}</ref> However, studies conducted analysing anatomical and genetic differences between the current ''Mandrillus'' and ''Papio'' genera showed more differences than similarities resulting in the current taxonomic ranking.<ref>{{Cite journal|last=Science|first=American Association for the Advancement of|date=1999-02-12|title=When Is a Mandrill Not a Baboon?|url=https://www.science.org/doi/10.1126/science.283.5404.931a|journal=Science|language=en|volume=283|issue=5404|pages=931|doi=10.1126/science.283.5404.931a|s2cid=81792789|issn=0036-8075|url-access=subscription}}</ref><ref>{{Cite journal|last=Disotell|first=Todd R.|date=1994|title=Generic level relationships of the Papionini (Cercopithecoidea)|journal=American Journal of Physical Anthropology|language=en|volume=94|issue=1|pages=47–57|doi=10.1002/ajpa.1330940105|pmid=8042705|issn=1096-8644}}</ref> Furthermore, the studies showed ''Mandrillus'' are more closely related to the white eyed mangabeys, and diverged relatively recently (4 million years ago) from this genus.<ref name="Dixson, Alan F." />

=== Species ===
{{Species table |genus=Mandrillus |authority-name= Ritgen |authority-year=1824 |species-count=two|no-note=y|narrow-percent=75}}
{{Species table/row
|name=[[Drill (animal)|Drill]] |binomial=M. leucophaeus
|image=File:Drill Monkey.jpg |image-alt=Gray monkey
|authority-name=[[Frédéric Cuvier|F. Cuvier]] |authority-year=1807 |authority-not-original=yes
|subspecies={{Collapsible list |expand=yes |title=Two subspecies |bullets=on
| ''M. l. leucophaeus'' ([[Mainland drill]])
| ''M. l. poensis'' ([[Bioko drill]])
}}
|range=Western Africa |range-image=File:Drill range map.svg |range-image-size=180px
|size={{convert|61|–|77|cm|in|0|abbr=on}} long, plus {{convert|5|–|8|cm|in|0|abbr=on}} tail<ref name="ADWDrill"/>
|habitat=Forest, savanna, and rocky areas<ref name="IUCNDrill"/>
|hunting=Omnivorous, primarily fruit and seeds<ref name="IUCNDrill"/>
|iucn-status=EN |population=4,000
|direction={{decrease|Population declining}}<ref name="IUCNDrill"/>
}}
{{Species table/row
|name=[[Mandrill]] |binomial=M. sphinx
|image=File:Mandrill_Albert_September_2015_Zoo_Berlin_(2).jpg |image-alt=Gray and brown monkey
|authority-name=[[Carl Linnaeus|Linnaeus]] |authority-year=1758 |authority-not-original=yes
|range=Western Africa |range-image=File:Mandrill_area.png |range-image-size=180px
|size={{convert|55|–|95|cm|in|0|abbr=on}} long, plus {{convert|7|–|10|cm|in|0|abbr=on}} tail<ref name="FieldAfrica129"/>
|habitat=Forest<ref name="IUCNMandrill"/>
|hunting=Fruit, seeds, fungi, roots, insects, snails, worms, frogs, and lizards, as well as snakes and small vertebrates<ref name="ADWMandrill"/>
|iucn-status=VU |population=Unknown
|direction={{decrease|Population declining}}<ref name="IUCNMandrill"/>
}}

{{Species table/end}}

== Anatomy ==
[[File:Mandrillus_leucophaeus_01_MWNH_297.jpg|alt=|left|thumb|265x265px|''Mandrillus leucophaeus'' skull]]
Both species of ''Mandrillus'' develop extremely large muzzles, prominent nasal ridges and paranasal swelling (swelling in the area adjacent to the nostrils). The size and colour of the paranasal swellings correlate to male dominance and rank, while the size of nasal ridges is a way of attracting mates.<ref name="Lehman">Lehman, S., & Fleagle, J. (2006). Primate Biogeography Progress and Prospects . Boston, MA: Springer US.</ref> ''Mandrillus'' teeth consist of two incisors, two premolars, one canine and three molars in each half of the upper and lower jaw, totalling 32 teeth.<ref name="Dixson, Alan F." /> Furthermore ''Mandrillus'' display larger premolars and extended canines; these dental traits are better adapted to crushing hard objects. This is due to a large part of their diet consisting of hard, dry nuts and seeds that require greater crushing power and the use of their teeth in ripping apart rotting wood to search for insects and other invertebrates.<ref name="Fleagle-2002">{{Cite journal|last1=Fleagle|first1=John G.|last2=McGraw|first2=W. Scott|date=2002-03-01|title=Skeletal and dental morphology of African papionins: unmasking a cryptic clade|url=http://www.sciencedirect.com/science/article/pii/S0047248401905263|journal=Journal of Human Evolution|language=en|volume=42|issue=3|pages=267–292|doi=10.1006/jhev.2001.0526|pmid=11846531|bibcode=2002JHumE..42..267F |issn=0047-2484|url-access=subscription}}</ref>
[[File:Mandrillus_sphinx_MNHN.jpg|left|thumb|''Mandrillus sphinx'' skull and shoulder blade]]
Within the shoulder and upper arm structures of the ''Mandrillus'' monkeys a deep scapular, broad deltoid plane, narrow stable elbow region and other skeletal features indicate the use of the forelimbs for climbing and foraging.<ref>{{Cite journal|last1=Fleagle|first1=John G.|last2=McGraw|first2=W. Scott|date=1999-02-02|title=Skeletal and dental morphology supports diphyletic origin of baboons and mandrills|journal=Proceedings of the National Academy of Sciences|language=en|volume=96|issue=3|pages=1157–1161|doi=10.1073/pnas.96.3.1157|issn=0027-8424|pmc=15367|pmid=9927710|doi-access=free|bibcode=1999PNAS...96.1157F }}</ref> This is used by the monkeys to climb trees when searching for ripe fruit and in the aggressive foraging of the forest floor in search of food.<ref name="Fleagle-2002" /> ''Mandrillus'' monkeys have developed an extremely broad and robust [[ilium (bone)|ilium]], and a rounded [[tibia]]l shaft. The development of these features can be attributed to the climbing of trees and quadrupedal locomotion. The largest toe is separated from the remaining toes for increased grasping power when climbing trees.<ref name="Dixson, Alan F." />

=== Sexual dimorphism ===
Both species of ''Mandrillus'' demonstrate a great degree of [[sexual dimorphism]] in weight, anatomy and physical appearance. The mandrill displays the most extreme sexual dimorphism for weight among all primates, with a male-female weight ratio of 3.2 – 3.4 at eight to ten years of age.<ref>{{Cite journal|last1=Setchell|first1=Joanna M.|last2=Lee|first2=Phyllis C.|last3=Wickings|first3=E. Jean|last4=Dixson|first4=Alan F.|date=2001|title=Growth and ontogeny of sexual size dimorphism in the mandrill (Mandrillus sphinx)|journal=American Journal of Physical Anthropology|language=en|volume=115|issue=4|pages=349–360|doi=10.1002/ajpa.1091|pmid=11471133|issn=1096-8644}}</ref> Similarly, drills are one of the most sexually dimorphic primates for body weight, with a male growing up to 32&nbsp;kg while a female grows to 12&nbsp;kg. Sexual dimorphism is also displayed in the growth of the craniofacial bones of both species.<ref name="Elton-2006">{{Cite journal|last1=Elton|first1=Sarah|last2=Morgan|first2=Bethan J.|date=2006-04-01|title=Muzzle size, paranasal swelling size and body mass in ''Mandrillus leucophaeus''|journal=Primates|language=en|volume=47|issue=2|pages=151–157|doi=10.1007/s10329-005-0164-6|pmid=16317498|s2cid=13602724|issn=1610-7365|url=http://dro.dur.ac.uk/17049/1/17049.pdf}}</ref> The males of each species have longer muzzles, much larger paranasal swellings and longer canines than their female counterparts. In a study of wild drills, female muzzles only grew up to 70% the length of the male muzzles.<ref name="Dixson, Alan F." /><ref name="Elton-2006" /> Furthermore, males have brightly coloured, saturated rumps unlike their female counterparts.<ref name="Dixson, Alan F." /> Both species also display the greatest visual sexual dimorphism within monkeys. On a scale based on rating the differences in physical features between genders, the mandrill obtained 32 whilst the drill obtained 24.5.<ref name="Dixson, Alan F." /> These ratings are based on features such as the saturation and colour of the rump (and face for mandrills), the paranasal swelling, the fatted rump and fur colouring.<ref name="Dixson, Alan F." />

== Distribution and habitat ==
''Mandrillus'' monkeys have a very localised biographical region located in West central Africa. The two species are often considered allopatric,<ref name="Lehman" /><ref name="Dixson, Alan F." /> they occupy non-overlapping regions, and their regions are divided by a physical barrier, the [[Sanaga River|Sanaga river]] in Cameroon. ''Mandrillus leucophaeus'' occupy the area above the river in North western [[Cameroon]] and southwestern [[Nigeria]] up until the [[Cross River (Nigeria)|Cross River]], and [[Bioko Island]] (Equatorial Guinea) which lies off the coast.<ref name="Lehman" /><ref name="Dixson, Alan F." />  The mandrill occupies the area below the river line in Cameroon, [[Río Muni]], [[Gabon]] and Congo.<ref name="Lehman" /> The ''Mandrillus'' species occupy multiple sections of the [[Guinean Forests of West Africa|Guinean forests of West Africa]], including [[Cross–Sanaga–Bioko coastal forests]] and [[Cameroonian Highlands forests]].<ref>{{Cite web|title=Western Africa: Coastal parts of Cameroon, Equator {{!}} Ecoregions {{!}} WWF|url=https://www.worldwildlife.org/ecoregions/at0107|website=World Wildlife Fund|language=en|access-date=2020-04-19}}</ref><ref name="Lehman" /> The forests the monkeys occupy have a humid, tropical climate and rugged terrain. Deforestation has reduced the habitat of both ''Mandrillus'' species, reducing the distribution of each species, especially the drill.<ref name="Dixson, Alan F." />

== Behaviour ==

=== Diet ===
Both ''Mandrillus'' species are frugivores, consuming both plants and insects with a preference for fruits and nuts. ''Mandrillus'' species spend a large amount of their time foraging through the forest in search of food.<ref name="Nsi Akoue-2017">{{Cite journal|last1=Nsi Akoue|first1=Gontran|last2=Mbading-Mbading|first2=Wilfried|last3=Willaume|first3=Eric|last4=Souza|first4=Alain|last5=Mbatchi|first5=Bertrand|last6=Charpentier|first6=Marie J. E.|date=September 2017|editor-last=Tregenza|editor-first=T.|title=Seasonal and individual predictors of diet in a free-ranging population of mandrills|journal=Ethology|language=en|volume=123|issue=9|pages=600–613|doi=10.1111/eth.12633|bibcode=2017Ethol.123..600N }}</ref> In a study conducted in Cameroon, approximately 84% of the faecal matter of mandrills consisted of fruit.<ref name="Dixson, Alan F." /> Similarly, a study done on drills in southwest Cameroon showed that the mean weight of fruit and seed in faecal matter was equal to or greater than 80%.<ref>{{Cite journal|last1=Astaras|first1=C.|last2=Waltert|first2=M.|date=December 2010|title=What does seed handling by the drill tell us about the ecological services of terrestrial cercopithecines in African forests?: Terrestrial forest primates' role in forest dynamics|journal=Animal Conservation|language=en|volume=13|issue=6|pages=568–578|doi=10.1111/j.1469-1795.2010.00378.x|s2cid=82430448 }}</ref> Seasonal changes can be seen within ''Mandrillus'' diet, during peak fruit season (September to March) their diet consisted mostly of fruit, pulp and seeds whilst during the fruit scarce season (June to August) there was a great increase in the consumption of insects, woody tissue and especially nuts.<ref name="Hongo-2018">{{Cite journal|last1=Hongo|first1=Shun|last2=Nakashima|first2=Yoshihiro|last3=Akomo-Okoue|first3=Etienne François|last4=Mindonga-Nguelet|first4=Fred Loïque|date=February 2018|title=Seasonal change in diet and habitat use in wild mandrills (''Mandrillus sphinx'')|journal=International Journal of Primatology|language=en|volume=39|issue=1|pages=27–48|doi=10.1007/s10764-017-0007-5|issn=0164-0291|hdl=2433/230380|s2cid=32935826|hdl-access=free}}</ref><ref name="Dixson, Alan F." /> There was also an increase in the variation of the diet during the fruit-scarce season.<ref name="Hongo-2018" /><ref name="Astaras-2008">{{Cite journal|last1=Astaras|first1=Christos|last2=Mühlenberg|first2=Michael|last3=Waltert|first3=Matthias|date=March 2008|title=Note on drill (''Mandrillus leucophaeus'') ecology and conservation status in Korup National Park, Southwest Cameroon|journal=American Journal of Primatology|language=en|volume=70|issue=3|pages=306–310|doi=10.1002/ajp.20489|pmid=17922527|s2cid=21284777}}</ref> Important fruit include but are not limited to, the fruit of the bush mango (''[[Irvingia gabonensis]]''), African Corkwood tree (''[[Musanga cecropioides]]''), ''Grewia coriacea'', ''Sacoglottis gabonensis'' and ''[[Xylopia aethiopica]]''. Invertebrates consumed include crickets, ants, caterpillars and termites. Rarely, ''Mandrillus'' monkeys will eat larger animals, such as rats and gazelles when presented with the opportunity.<ref name="Nsi Akoue-2017" /><ref name="Dixson, Alan F." /><ref name="Astaras-2008" />

=== Social systems ===
The species of the genus exhibit great similarities in their social systems. Both generally form smaller groups, however the size of these groups is unclear. A study done on drills in southwest Cameroon found a mean group size of 52.3<ref name="Astaras-2008" /> while another more recent report stated a figure of 25–40 on these smaller groups.<ref name="Marty-2009">{{Cite journal|last1=Marty|first1=Jill S.|last2=Higham|first2=James P.|last3=Gadsby|first3=Elizabeth L.|last4=Ross|first4=Caroline|date=December 2009|title=Dominance, coloration, and social and sexual behavior in male drills ''Mandrillus leucophaeus''|journal=International Journal of Primatology|language=en|volume=30|issue=6|pages=807–823|doi=10.1007/s10764-009-9382-x|s2cid=38938846|issn=0164-0291}}</ref>  A study of mandrills done at Campo reserve in Cameroon found small groups contain 14 - 95 individuals.<ref name="Dixson, Alan F." /> These smaller groups, with stable social structures, often join to form larger "supergroups" of hundreds of individuals.<ref name="Marty-2009" /> Some of the largest mandrill "supergroups" reported contained up to 845 individuals whilst some of the largest drill "supergroups" reported contained 400 individuals.<ref name="Nsi Akoue-2017" /><ref name="Dixson, Alan F." /> There have been reports of solitary male ''Mandrillus'' monkeys, however this occurs very rarely.<ref name="Dixson, Alan F." />

The social structures and social hierarchy of ''Mandrillus'' "supergroups" and groups is highly contentious. There are multiple older (1970s-1990s) sources referencing single male units, which contained a male and multiple female monkeys, as the smallest and most common stable social structure. However this has been disproved with the discovery of less colourful male ''Mandrillus'' and further observations of behaviour.<ref name="Dixson, Alan F." /><ref name="Bret-2013">{{Cite journal|last1=Bret|first1=Céline|last2=Sueur|first2=Cédric|last3=Ngoubangoye|first3=Barthélémy|last4=Verrier|first4=Delphine|last5=Deneubourg|first5=Jean-Louis|last6=Petit|first6=Odile|date=2013-12-10|editor-last=Engelhardt|editor-first=Antje|title=Social structure of a semi-free ranging group of mandrills (''Mandrillus sphinx''): a social network analysis|journal=PLOS ONE|language=en|volume=8|issue=12|pages=e83015|doi=10.1371/journal.pone.0083015|issn=1932-6203|pmc=3858359|pmid=24340074|doi-access=free|bibcode=2013PLoSO...883015B }}</ref><ref name="Astaras-2008" /><ref>{{Cite journal|last=Hongo|first=Shun|date=2014-10-01|title=New evidence from observations of progressions of mandrills (''Mandrillus sphinx''): a multilevel or non-nested society?|journal=Primates|language=en|volume=55|issue=4|pages=473–481|doi=10.1007/s10329-014-0438-y|pmid=25091875|issn=1610-7365|hdl=2433/200186|s2cid=15104161|hdl-access=free}}</ref> ''Mandrillus leucophaeus'' social structures are unknown, due to low populations, and secluded habitats with dense forestry.<ref name="Marty-2009" /> On the other hand, ''Mandrillus sphinx'' has had a variety of studies on social structure done in largely captive and semi-free ranging settings, with few studies on wild mandrills. The current studies on mandrills are inconclusive, and present different results. Various semi-free ranging studies conducted report a matrilineal social structure with a stable infant and female mandrill "supergroup". Male ''Mandrillus'' monkeys would disperse from this group when old enough and join other groups only during mating season.<ref name="Bret-2013" /><ref name="Dixson, Alan F." /> Further studies, also done in semi-free ranging settings, conclude that dominant females are central to group cohesion and connectivity (how close they remained).<ref name="Dixson, Alan F." /><ref name="Bret-2013" /> Conversely, a study on wild mandrills published in 2015 reported that a stable adult, male mandrill population of 5 - 6 was present year round in "supergroups".<ref name="Brockmeyer-2015">{{Cite journal|last1=Brockmeyer|first1=Timo|last2=Kappeler|first2=Peter M.|last3=Willaume|first3=Eric|last4=Benoit|first4=Laure|last5=Mboumba|first5=Sylvère|last6=Charpentier|first6=Marie J.E.|date=October 2015|title=Social organization and space use of a wild mandrill ( Mandrillus sphinx ) group: Mandrill Social Organization and Space Use|journal=American Journal of Primatology|language=en|volume=77|issue=10|pages=1036–1048|doi=10.1002/ajp.22439|pmid=26235675|s2cid=38327403}}</ref> This aligned with the social structures reported in other research papers done on wild mandrills, where stable multi-male and multi-female groups were found.<ref>{{Cite journal|last=Harrison|first=Michael J. S.|date=October 1988|title=The mandrill in Gabon's rain forest—ecology, distribution and status|journal=Oryx|language=en|volume=22|issue=4|pages=218–228|doi=10.1017/S0030605300022365|issn=0030-6053|doi-access=free}}</ref><ref name="Brockmeyer-2015" /><ref name="Astaras-2008" /> This difference in social structures between ''Mandrillus'' groups has been attributed to limitations in observing wild mandrills, differing habitats, and differing sample sizes.<ref name="Bret-2013" />

Male dominance and rank have been linked to the colouration and colour extension of the rumps, greater saturation and colour extension correlated to higher-ranking males. Males of higher ranking are more likely to associate with females, especially those with sexual skin swelling, and more likely to successfully mount females.<ref name="Marty-2009" /><ref name="Dixson, Alan F." /> Dominant, adult males practice mate guarding on adult females during times of maximal skin swelling; with their high competitive ability they are more likely to successfully reproduce.<ref name="Marty-2009" /> Due to the tropical habitat, mating season coincides with the dry season (May to October) and birth season coincides with the wet season (November to April).<ref name="Dixson, Alan F." />

=== Communication ===
[[File:Mandrillus_sphinx_(alpha_male).jpg|thumb|Mandrill displaying silent baring of teeth]]
The ''Mandrillus'' genus uses both visual and vocal forms of communication, which are extremely similar or identical across both species. Both species have three identical long-range vocal communications: two-phase grunts, roars and "crowling".<ref name="Dixson, Alan F." /> The two-phased grunt is a low, two-syllable continuous sound used exclusively by adult males during calm group progression and mate guarding.<ref name="Kudo-1987">{{Cite journal|last=Kudo|first=Hiroko|date=July 1987|title=The study of vocal communication of wild mandrills in Cameroon in relation to their social structure|journal=Primates|volume=28|issue=3|pages=289–308|doi=10.1007/bf02381013|s2cid=1507136|issn=0032-8332}}</ref> Roars are single low, single syllable sounds used exclusively by males in the same context as two-phase grunts. Crowling is used by infants and females during group movement or foraging to call together the dispersed group.<ref name="Kudo-1987" /><ref name="Dixson, Alan F." /><ref>{{Cite book|last=Astaras, Christos.|title=Ecology and status of the drill (''Mandrillus leucophaeus'') in Korup National Park, Southwest Cameroon : implications for conservation|date=2009|publisher=Optimus Mostafa|isbn=978-3-941274-19-8|edition=1.|location=Göttingen|oclc=434519864}}</ref>

They also use numerous short-range vocal sounds for various purposes. The "yak" and grinding of teeth are used during tense situations. The grunt is used in aggressive situations and screams are used to escape or while experiencing fear. The growl is used to convey mild alarm, the K-alarm is used to convey intense alarm and the "girney" is used for appeasement.<ref name="Kudo-1987" /> Both species use various facial expressions to communicate with each other. The silent baring of teeth is a positive visual signal conveying peaceful intentions, and it is often combined with a shaking head.<ref>{{Cite journal|last1=Bout|first1=N.|last2=Thierry|first2=B.|date=December 2005|title=Peaceful Meaning for the Silent Bared-Teeth Displays of Mandrills|journal=International Journal of Primatology|language=en|volume=26|issue=6|pages=1215–1228|doi=10.1007/s10764-005-8850-1|s2cid=31905432|issn=0164-0291}}</ref> Staring open-mouthed is a display of aggression, frowning with bare teeth is used to encourage submission, staring with bare teeth can communicate aggression or fear, pouting signals submission and a relaxed open mouth encourages playing.<ref name="Dixson, Alan F." />

== Conservation status ==
The current conservation status of ''Mandrillus sphinx'' is vulnerable and that for ''Mandrillus leucophaeus'' is endangered.<ref name="IUCNDrill"/><ref name="IUCNMandrill"/> The greatest threats to the conservation of this genus are the severe loss and degradation of their habitat, and hunting.<ref name="Morgan-2013">{{Cite journal|last1=Morgan|first1=Bethan J.|last2=Abwe|first2=Ekwoge E.|last3=Dixson|first3=Alan F.|last4=Astaras|first4=Christos|date=2013-04-01|title=The Distribution, Status, and Conservation Outlook of the Drill (Mandrillus leucophaeus) in Cameroon|journal=International Journal of Primatology|language=en|volume=34|issue=2|pages=281–302|doi=10.1007/s10764-013-9661-4|s2cid=14417124|issn=1573-8604}}</ref><ref>{{Cite book|last=Olney, P. J. S.|title=Creative Conservation : Interactive management of wild and captive animals|date=1994|publisher=Springer Netherlands|others=Mace, G. M., Feistner, A. T. C.|isbn=978-94-011-0721-1|location=Dordrecht|oclc=840308626}}</ref> The loss of habitat is an ongoing threat that can be attributed to the expansion of human settlements as well as the clearing of forests for chipping factories and agriculture. Hunting and poaching of ''Mandrillus'' monkeys for meat or to protect crops is also major, ongoing threat to the population despite the implementation of hunting restrictions and sanctuaries.<ref name="IUCNMandrill"/><ref name="IUCNDrill"/> The drill population in Cameroon, which encompasses 80% of the drill's original habitat, has been fragmented into smaller, isolated populations with largest residing in Korup national park.<ref name="Morgan-2013" /> The mandrill population in south Cameroon and Equatorial Guinea are at great risk due to extensive forest loss. The majority of the mandrill population remains in Gabon and faces major threats from railroad construction and logging companies.<ref name="Dixson, Alan F." /> As of 2020, the mandrill population is in decline while the drill population is not able to be accurately determined.<ref name="IUCNMandrill"/><ref name="IUCNDrill"/>

==References==
{{Reflist|refs=
<ref name="IUCNDrill">{{cite iucn |last1=Gadsby |first1=E. L. |last2=Cronin |first2=D. T. |last3=Astaras |first3=C. |last4=Imong |first4=I. |title=''Mandrillus leucophaeus'' |volume=2020 |page=e.T12753A17952490 |date=2020 |doi=10.2305/IUCN.UK.2020-2.RLTS.T12753A17952490.en}}</ref>
<ref name="ADWDrill">{{cite web |first1=Ken |last1=Briercheck |title=''Mandrillus leucophaeus'' |url=https://animaldiversity.org/accounts/Mandrillus_leucophaeus/ |date=2023 |website=[[Animal Diversity Web]] |publisher=[[University of Michigan]] |access-date=August 16, 2023 |archive-date=July 18, 2023 |archive-url=https://web.archive.org/web/20230718184140/https://animaldiversity.org/accounts/Mandrillus_leucophaeus/ |url-status=live }}</ref>
<ref name="IUCNMandrill">{{cite iucn |last1=Abernethy |first1=K. |last2=Maisels |first2=F. |title=''Mandrillus sphinx'' |volume=2019 |page=e.T12754A17952325 |date=2019 |doi=10.2305/IUCN.UK.2019-3.RLTS.T12754A17952325.en}}</ref>
<ref name="ADWMandrill">{{cite web |first1=Lisa |last1=Ingmarsson |title=''Mandrillus sphinx'' |url=https://animaldiversity.org/accounts/Mandrillus_sphinx/ |date=2023 |website=[[Animal Diversity Web]] |publisher=[[University of Michigan]] |access-date=August 16, 2023 |archive-date=May 15, 2023 |archive-url=https://web.archive.org/web/20230515181419/https://animaldiversity.org/accounts/Mandrillus_sphinx/ |url-status=live }}</ref>
<ref name="FieldAfrica129">[[#CITEREF_AfricanMammals|Kingdon 2015]], p. 129</ref>
}}

==Sources==
{{Refbegin}}
* {{cite book |title=The Kingdon Field Guide to African Mammals |edition=Second |last=Kingdon |first=Jonathan |date=2015 |publisher=[[Bloomsbury Publishing]] |isbn=978-1-4729-2531-2 |ref=CITEREF_AfricanMammals}}
{{Refend}}

==External links==
{{Commons category|Mandrillus}}
{{Wikispecies|Mandrillus}}
* [http://pin.primate.wisc.edu/factsheets/links/mandrillus Primate Info Net ''Mandrillus'' Factsheets]

{{C.Cercopithecinae nav}}
{{Haplorhini|C.}}
{{Taxonbar|from=Q798426}}
{{Authority control}}

[[Category:Mandrillus| ]]
[[Category:Papionini]]
[[Category:Primate genera]]
[[Category:Primates of Africa]]
[[Category:Taxa named by Ferdinand August Maria Franz von Ritgen]]
[[Category:Taxa described in 1824]]