---
title: "What the sources say about the Mandrill | AnimalTracks.wiki"
description: "66 claims from the Mandrill profile, each beside the words of the source that backs it."
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canonical: "https://animaltracks.wiki/animals/mandrill/sources/"
---

# What the sources say about the Mandrill (*Mandrillus sphinx*)

> 66 claims from the Mandrill profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Mandrill](https://animaltracks.wiki/animals/mandrill/)

## Mandrillus sphinx (mandrill). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Mandrillus_sphinx/

| The page says | The source says |
| :--- | :--- |
| southwestern Cameroon, western Gabon, Equatorial Guinea, and southwestern Congo | Mandrills are found in southwestern Cameroon, western Gabon, Equatorial Guinea, and southwestern Congo. |
| Fruit, seeds, fungi, roots, and insects, plus snails, worms, frogs, lizards, and sometimes snakes and small vertebrates | Mandrills have a highly varied diet including fruit, seeds, fungi, roots, insects, snails, worms, frogs, lizards, and sometimes snakes and even small vertebrates. |
| blue ridges run down each side of the muzzle, with a red stripe down its middle and around the nostrils | A mandrill's face has a red stripe down the middle of the muzzle and aroung the nostrils, while the sides of the muzzle are ridged lengthwise and colored blue. |
| Mandrills live in southwestern Cameroon, western Gabon, Equatorial Guinea, and southwestern Congo | Mandrills are found in southwestern Cameroon, western Gabon, Equatorial Guinea, and southwestern Congo. |
| They eat fruit, seeds, fungi, roots, and insects, plus snails, worms, frogs, lizards, and sometimes snakes and small vertebrates. | Mandrills have a highly varied diet including fruit, seeds, fungi, roots, insects, snails, worms, frogs, lizards, and sometimes snakes and even small vertebrates. |
| tags: omnivore | Mandrills have a highly varied diet including fruit, seeds, fungi, roots, insects, snails, worms, frogs, lizards, and sometimes snakes and even small vertebrates. |

## Mandrill. San Diego Zoo Wildlife Alliance.

https://animals.sandiegozoo.org/animals/mandrill

| The page says | The source says |
| :--- | :--- |
| Males are the largest monkeys alive | The male mandrill is the largest living monkey. |
| Mandrills live in small social units that often join other groups to form larger ones called hordes. | Mandrills live in small social units, but often join up with other small groups to form larger ones called hordes. |
| One of the largest groups documented numbered more than 1,200 mandrills. | One of the largest groups documented numbered over 1,200 mandrills! |
| Hordes are noisy, keeping in touch with deep grunts and high-pitched screams while they forage and travel. | Mandrill hordes are noisy. They communicate with deep grunts and high-pitched screams while they forage and travel. |
| Male mandrills are the largest monkeys alive | The male mandrill is the largest living monkey. |
| Males rub it on objects | Male mandrills have a scent gland on their chest that they rub on objects |
| Males weigh 18 to 33 kilograms (about 55 pounds) | males, 55 pounds (18 to 33 kilograms) (note: about 55 pounds is the page's own figure for males, with 18 to 33 kilograms in brackets.) |
| stand about 80 centimeters (32 inches) tall | males, about 32 inches (62 to 110 centimeters) (note: 80 centimeters is the rounded conversion of the page's 32 inches; ADW gives the same height ('about 80 cm').) |
| Females are about half their size | They are also much smaller, about half the size of the adult males. |
| at 11 to 13 kilograms (about 25 pounds) | Weight: Females, 25 pounds (11 to 13 kilograms) |
| In human care, a mandrill's median life expectancy is about 20 years. | For mandrills in managed care, median life expectancy is about 20 years |
| Mandrill canine teeth can be more than 5 centimeters (2 inches) long | canine teeth, which can be over 2 inches (5 centimeters) long |
| Males spend most of their time foraging on the ground, while females and young find food in the trees | Male mandrills spend most of their time on the ground, foraging for seeds, nuts, fruits, and small animals. Females and youngsters find their food in the trees. |
| mandrills climb trees to sleep, picking a different tree each evening | They do climb trees, though, and even sleep there, selecting a different tree each evening. |
| Small units often join up into larger groups called hordes | Mandrills live in small social units, but often join up with other small groups to form larger ones called hordes. |
| one of the largest documented numbered more than 1,200 mandrills | One of the largest groups documented numbered over 1,200 mandrills! |
| Illegal logging, forest clearing for farms, and the growing commercial bushmeat trade threaten it. | Conservation organizations are working to protect mandrill habitat from illegal logging and the growing commercial bushmeat trade. ... mandrills are losing their habitat to logging and clearing of forests for agricultural use. |
| dangerLevel: High | This is no slight gesture, as the mandrill is strong and muscular with powerful limbs. This is a convincing hint to back off! (note: High is 'Dangerous when cornered or provoked'. SDZ also gives canines over 5 cm.) |

## Abernethy & Maisels (2019). Mandrillus sphinx. The IUCN Red List of Threatened Species 2019: e.T12754A17952325.

https://doi.org/10.2305/iucn.uk.2019-3.rlts.t12754a17952325.en

| The page says | The source says |
| :--- | :--- |
| The IUCN lists the species as Vulnerable. | IUCN Red List category: Vulnerable (VU). |

## Renoult et al. (2011). The Evolution of the Multicoloured Face of Mandrills: Insights from the Perceptual Space of Colour Vision. PLoS ONE.

https://doi.org/10.1371/journal.pone.0029117

| The page says | The source says |
| :--- | :--- |
| faces colored blue by light-scattering collagen | blue colouration results from coherent scattering of light by quasi-ordered arrays of dermal collagen fibrils |
| and red by blood | red skin colouration is induced by haemoglobins in blood flow |
| Skin colored blue by light-scattering collagen | blue colouration results from coherent scattering of light by quasi-ordered arrays of dermal collagen fibrils |
| red by blood, both most saturated in the top-ranked males | Top-ranked males are the most saturated for both blue and red colours |
| collagen fibers in the skin, the protein that makes skin tough, are laid out in nearly regular arrays that scatter light into blue | blue colouration results from coherent scattering of light by quasi-ordered arrays of dermal collagen fibrils |
| the protein that makes skin tough | the primary role of collagen to confer skin resistance |
| The red comes from blood. Top-ranked males have the most testosterone, which saturates red skin by widening its blood vessels. | top-ranked males have the highest levels of circulating testosterone [36] , which causes red saturated skins by peripheral vasodilatation |
| The blue comes from coherent scattering: collagen fibers in the skin | blue colouration results from coherent scattering of light by quasi-ordered arrays of dermal collagen fibrils |
| the protein that makes skin tough, are laid out in nearly regular arrays that scatter light into blue | blue colouration results from coherent scattering of light by quasi-ordered arrays of dermal collagen fibrils [27] . Although the evolution of blue hue may be constrained by the primary role of collagen to confer skin resistance |
| The red comes from blood. | red skin colouration is induced by haemoglobins in blood flow |
| The more saturated the colors, the higher the rank. | Higher-ranking males have more saturated blues and reds than lower-ranking males |
| Researchers who measured facial color in 34 adult males | we recorded colour spectra of 34 mature males |
| living in forested enclosures at a medical research center in Gabon | Centre International de Recherches Médicales de Franceville’, Gabon (CIRMF) in naturally forested enclosures |
| higher-ranking males carry more saturated blue and red than lower-ranking ones | Higher-ranking males have more saturated blues and reds than lower-ranking males |
| the contrast between the two colors indicates rank more accurately than either color alone | although blue saturation, red saturation and the contrast between blue and red colours are all correlated with dominance, dominance is most accurately indicated by the blue-red contrast |
| Top-ranked males also have the most testosterone, which saturates red skin by widening its blood vessels. | top-ranked males have the highest levels of circulating testosterone [36] , which causes red saturated skins by peripheral vasodilatation |
| His blue comes from collagen fibers laid out in near-regular arrays that scatter light | blue colouration results from coherent scattering of light by quasi-ordered arrays of dermal collagen fibrils (note: vibe.reason (#692/#693)) |
| his red from blood, and the more saturated both colors, the higher he ranks | Top-ranked males are the most saturated for both blue and red colours (note: vibe.reason (#692/#693)) |
| his red from blood | red skin colouration is induced by haemoglobins in blood flow (note: vibe.reason (#692/#693)) |

## Setchell & Dixson (2001). Changes in the Secondary Sexual Adornments of Male Mandrills (Mandrillus sphinx) Are Associated with Gain and Loss of Alpha Status. Hormones and Behavior.

https://doi.org/10.1006/hbeh.2000.1628

| The page says | The source says |
| :--- | :--- |
| In a study of two groups in similar enclosures | Two semifree-ranging mandrill groups, inhabiting large, naturally rainforested enclosures in Gabon |
| the four males who rose to alpha rank gained testosterone and redder skin on the face and genitals | Gaining alpha rank (N = 4 males) resulted in increased testicular size and circulating testosterone, reddening of the sexual skin on the face and genitalia |
| the four who lost alpha rank saw their red patches shrink. Blue stayed the same either way. | Blue sexual skin coloration was unaffected. ... Loss of alpha position (N = 4 males) resulted in less pronounced effects than those that occurred after males had risen to alpha positions. Deposed alpha males showed decreased testicular volume, decreased body mass, a reduction in the extent of red (but not blue) sexual skin coloration |
| A change in rank shows on the skin. | Secondary sexual traits respond to changes in male social status |

## Leigh et al. (2008). Canine tooth size and fitness in male mandrills (Mandrillus sphinx). Journal of Human Evolution.

https://doi.org/10.1016/j.jhevol.2008.01.001

| The page says | The source says |
| :--- | :--- |
| canine teeth whose length tracks their breeding years | These factors combine to constrain male reproductive opportunities to a brief timespan, defined by the period of maximum canine length. |
| males fathered offspring almost exclusively once their canines passed roughly 30 millimeters, about two-thirds of the average adult length of 45 millimeters | Male mandrills sire offspring almost exclusively when their canines exceed approximately 30 mm, or two-thirds of average adult value (45 mm). |
| fathers had larger canines than males that sired none | Moreover, sires have larger canines than nonsires. |
| Wear shrinks the tooth with age, in step with the end of a male's breeding years. | The tooth diminishes through wear as animals age, corresponding with, and perhaps influencing, reproductive senescence. |
| A long-term study | This long-term study of mandrill monkeys (Mandrillus sphinx) |
| a long-term study tied them to breeding | This long-term study of mandrill monkeys (Mandrillus sphinx) demonstrates how age-related changes in canine tooth weaponry and adult canine size correlate closely with male lifetime reproductive success. |
| Males fathered offspring almost exclusively once their canines passed roughly 30 millimeters, about two-thirds of the average adult length of 45 millimeters | Male mandrills sire offspring almost exclusively when their canines exceed approximately 30 mm, or two-thirds of average adult value (45 mm). |
| fathers had larger canines than males that sired none | Moreover, sires have larger canines than nonsires. |
| Wear shrinks the tooth with age, in step with the end of a male's breeding years. | The tooth diminishes through wear as animals age, corresponding with, and perhaps influencing, reproductive senescence. |

## Setchell et al. (2010). Chemical Composition of Scent-Gland Secretions in an Old World Monkey (Mandrillus sphinx): Influence of Sex, Male Status, and Individual Identity. Chemical Senses.

https://doi.org/10.1093/chemse/bjp105

| The page says | The source says |
| :--- | :--- |
| A mandrill's chest carries a scent gland. | the presence of a sternal scent-gland in the mandrill |
| the chemical mix of its secretion carries the owner's sex and age, plus rank in males | volatile profiles convey both variable (age, dominance rank in males) and fixed (sex, possibly individual identity) information about the signaler |

## Harrison (1988). The mandrill in Gabon's rain forest - ecology, distribution and status. Oryx.

https://doi.org/10.1017/s0030605300022365

| The page says | The source says |
| :--- | :--- |
| Primary rainforest, and secondary forest too | The preferred habitat of mandrills is primary rain forest, although they do use secondary forest |
| preferring primary rainforest but also using secondary forest | The preferred habitat of mandrills is primary rain forest, although they do use secondary forest |
| Their natural predators are probably limited to leopards, crowned eagles, and possibly chimpanzees and some snakes. | Natural predators are probably limited to the leopard Panthera pardus, the crowned eagle Stephanoaetus coronatus, and potentially the chimpanzee Pan troglodytes and some of the snakes |
| In 1983 the researcher Michael Harrison was following a group of about 40 mandrills in Gabon when they flushed a leopard from a small cave. | In March 1983 in the Lope Reserve, I was following a group of some 40 individuals as they picked through the leaf litter in dense undergrowth that covered steep ravines, when they flushed a leopard from a small cave. |
| The mandrills scattered, screaming; most climbed into the lower canopy and kept watching the leopard as it walked calmly away. | The mandrills exploded into a confusion of scattering and screaming; most climbed into the lower canopy while keeping visual track of the leopard as he walked calmly away |
| Groups vary from 15 animals to aggregations of 250 or more | varying in size from small groups of 15 individuals to large aggregations of 250 or more |
| two studies found larger groups more common in the lesser fruiting season | Seasonal patterns in mandrill groupings were found by both Jouventin (1975) and Hoshino et al. (1984): small groups of mandrills were more common in the major fruiting season, while larger groups were more common in the minor fruiting season |