Deep within a dwindling expanse of rainforest in western Gabon, the bantering exchange of emphatic, heavy grunts and shrill cries moves steadily underneath the thick arboreal cover of Kapok Trees. The sounds reverberating throughout this evergreen ecosystem announce the arrival of a massive herd of Mandrills minutes before the first monkeys ever appear. When the first of the group's male leaders finally do emerge, the scenery of lush green vegetation suddenly showcases a distinctive spattering of vividly red snouts, bright blue cheeks, golden collars of fur, and technicolored behinds.
Behind these brilliantly colored males, dozens upon dozens of duller, smaller females follow, foraging for fruits, fungus, leaves, roots, and seeds. Sometimes, these omnivorous adults will use their dexterous hands to snatch up some small insects for an extra dose of protein and nutrients, and occasionally to catch a small mammal. While most food is devoured on the spot, large cheek pouches allow these monkeys to store some snacks for a later time if desired.
Scientists have observed well over a thousand Mandrills roving the rainforest together, but most troops only number in the hundreds - vastly populated by females and their offspring, supplemented by a collection of generally solitary males. As an extremely social animal, the world's largest monkey thrives in these large groups, often establishing home territories spanning 50-square kilometers (19-square miles). Within this area, these terrestrial creatures occupy most of their waking hours foraging for food, only abandoning the forest floor for the safety of tree branches when the sun sets over the Atlantic horizon. While pythons may stealthily slither through the canopy looking to swallow a small and vulnerable monkey, leopards present an equally if not more terrifying threat on the ground.
Mandrill mating occurs year-round, although the majority of offspring are born between the months of January and April after a gestation period of 6 to 7 months. After their sexual maturation during their fourth year, females cannot be bashful about their readiness and willingness to breed. Normally drably colored, the female's rump will swell in size and color, burning a bright red to signal receptivity. Making matters more obvious, female Mandrills will actively pursue their desired mate, following a male counterpart until - assuming he reciprocates interest - he turns around to commence intercourse.
All Mandrills possess similar physical features: strong limbs, small pointed ears poking out from the top of large heads, and large canines (up to 6.5 centimeters or 2.6 inches long) to intimidate predators or rivals. In proximity to one another, however, males and females show distinct differences in size and coloring. Within this sexually dimorphic species, females measure only about half as large as male partners - 56 centimeters tall (1.8 feet) compared to 81 centimeters (2.7 feet), and 14 kilograms (30.9 pounds) as opposed to 27 kilograms (59.5 pounds). Furthermore, while these more slender females display a duller patterning, male Mandrills are easily recognized thanks to their remarkably colorful facial features, which make them one of the most colorful mammals found in nature.
Along the length of the male's thin, bright red nose - which flares just above equally red lips into rather large nostrils - long hairless streaks of sky blue fill the space between beady eyes and strands of white whiskers. Beneath the mouth, a thick golden beard - and sometimes neck - contrasts an otherwise brownish olive coat of thick fur. And while females' rumps only glow when hormones are high, males constantly display a radiant rear, with patches of purple and red around the base of stubby tails, and bright blue and yellow hair covering most of the behind.
These colors only grow in intensity over time; male Mandrill infants emerge from the womb with eyes open and some fur, but most of the hairs are black and do not completely cover the base layer of pink skin. Despite having the immediate capacity to support their own weight, newborns will usually cling to their mother's grayed undersides for transportation around the jungle. Over the ensuing months, mother and child forge close bonds over communal activities such as feeding and grooming; daughters often maintain a relationship with their primary caretaker into adulthood, while males leave to assume their rogue lives upon maturity. By this time, both genders have fully developed brawny bodies and strong limbs.
Bound by the Sanaga River to the north, the Ogooue and Ivindo Rivers to the east, and the Congo River to the south, the world's wild Mandrills live in an extremely restricted space across the borders of four West African nations: Gabon, Cameroon, Equatorial Guinea, and the Republic of Congo. Like all species of animals whose homes are rainforests, Mandrills are tragic victims to the continuing deforestation that decimates what limited, precious territory remains. As native human populations seek to expand areas for crop cultivation and grazing livestock, local political leaders have little incentive to implement the necessary laws to deter deforestation in the name of wildlife conservation.
Habitat destruction may pose the most lethal threat to the future existence of Mandrillus sphinx - and has already played a primary role in the species' 30% decrease in global population over the past three decades - but other factors are exacerbating an already worrisome cause. Mandrill meat is considered a delicacy in western Africa, and given the monkey's behavioral tendency to travel in large groups, eluding human capture or gunfire becomes an almost impossible task. Dozens going on hundreds of individuals are slaughtered in fell swoops, and the absence of local government conservationist measures means Mandrills lack the necessary protection and advocacy that will ultimately be essential to their survival in the wild.
A group of Mandrills, led by a very large and highly colored male are shown moving through he edge of clearing in the Lope Reserve in central Gabon. The females in the male's harem are considerably smaller in size and far less brightly colored. One is depicted with a juvenile ridding on her back.