White-Cheeked Macaque, Macaca leucogenys
WHITE-CHEEKED MACAQUE
Macaca leucogenys
Geographic Distribution and Habitat
A birdwatching group from northeast India, composed of wildlife photographers and biologists, affirmed the discovery of the white-cheeked macaque (Macaca leucogenys) while visiting Mêdog county in southeastern Tibet in March 2015. It was in the Anjaw district of Arunachal Pradesh (a region claimed by India, China, and Taiwan with a related history of political conflicts) where a troop of white-cheeked macaques surprised the unsuspecting birders. As happenstance would have it, this new species was heralded just days earlier in the American Journal of Primatology with an account from a team of Chinese researchers who had set up camera traps in four Tibetan gorges. After reviewing many months of collected camera trap images (more than 700!), along with direct observations and photographs, the Chinese team was convinced they were looking at a “new monkey.”
Later scientific testing, including physical measurements and molecular diagnosis through DNA extracted from four collected skin specimens, would confirm the white-cheeked macaque as a distinct, previously unknown primate species and as one of the most important zoological discoveries of the decade.
Mêdog County remained the only known range of white-cheeked macaques for many years after their initial sighting, until a study published in 2022 announced their occurrence in the Anjaw and West Siang districts of Arunachal Pradesh, India, 570 miles (197 km) away from China. After surveying and collecting fecal and skin samples around the Eastern Himalaya, the team confirmed through DNA analysis that the samples belonged to the white-cheeked macaque. After this, they were also able to obtain video footage of the species in the wild, and even managed to find a juvenile white-cheeked macaque in captivity while canvassing the region.
Mêdog County is known for its network of diverse ecosystems and rich biodiversity. Arunachal Pradesh—known as the “land of dawn-lit mountains” and home to white-cheeked-macaques—is situated at the junction of the Eastern Himalayas and Indo-Burma regions.
This area is defined by alluvial, low-lying grasslands (created by river sediment), subtropical broadleaf forests (jungles), and alpine meadows that rise above the tree line at a wide altitudinal range, from 492 to 19,685 feet (150–6,000 m) above sea level. These newly recognized “whiskered” macaques take advantage of their varied habitat, residing within tropical forests at 4,577 feet (1,395 m), within primary and secondary evergreen broadleaf forests at 6,562 feet (2,000 m), and within mixed broadleaf-conifer forests at 8,858 feet (2,700 m).
The entire distribution of this species, based on the current sightings and reports, is listed at 8,905 square miles (23,063 km²)
Despite being first identified in 2015, it wasn’t until 2017 that white-cheeked macaques were confirmed as a unique species through DNA obtained from skin samples.
Although they share similarities with other macaques, such as the rhesus macaque (M. mulatta), Tibetan macaque (M. thibetana), Assamese macaque (M. assamensis), and Arunachal macaque (M. munzala), the white-cheeked macaque can be distinguished by its white whiskers on the face and chin, dark skin on the muzzle, and in males, a round genital shape rather than the arrow-shaped form typical of other macaque species.
A 2024 study examined the Y chromosome, which is passed from father to offspring, in two separate white-cheeked macaque populations. The researchers found two distinct paternal lineages: one related to the Assamese macaque and Arunachal macaque, and the other matching white-cheeked macaques from Tibet. This suggests that, many years ago, male macaques from different species interbred with white-cheeked macaques, a process that has likely played an important role in their evolution.
Size, Weight, and Lifespan
Macaques are medium- to large-sized monkeys with a body length ranging from 1.25 to 2.3 feet (38–71 cm) for adults, depending on the species. Tail length also varies with species, ranging from a stub to very long. Males are much heavier than females, an example of sexual dimorphism. An adult male macaque can weigh from 11 pounds to nearly 40 pounds (5–18 kg), compared to an adult female’s weight of 4.4 pounds to nearly 29 pounds (2–13 kg).
True to their genus (Macaca), white-cheeked macaques are robust, heavy-bodied monkeys. Nature has fitted them with a comparatively short tail that bends downward in some individuals. They are larger than Assam macaques (M. assamensis), who they resemble, but are similar in size to Tibetan macaques (Macaca thibetana).
Lifespan has not been reported for this species, but other similar macaque species live a relatively long life: up to 30 years.
Appearance
Long white whiskers that extend from the cheeks and chin give this newly named monkey its common name. Their whiskers begin growing as the monkeys reach adulthood, and their facial skin darkens. By the time white-cheeked macaques are fully mature, their faces—and even their ears—are covered by a furry, densely whiskered jungle. Only the dark-skinned muzzle and pinkish eyelids escape this hair-covered encroachment. As a finishing touch, Nature has painted a thin, dark stripe of fur beginning at the outer corner of each eye, or from the monkey’s upper cheek, and extending to each ear.
As with other macaques, the coloring of their fur coat (pelage) varies. Shades of light to dark brown and dark chocolate cloak their sturdy bodies. In most individuals, fur coloring of their gloriously unkempt ventrum (underside) is lighter than the even mantle of fur covering their dorsum (the back). The white-cheeked macaque’s short, hairless tail begs for no attention. A thick, hairy ruff is worn like a muffler around the neck and is a distinguishing feature of the species.
Males have another distinguishing feature: their penis. Unlike the arrow-shaped penis and white scrotums of sympatric macaque species, particularly their “lookalike cousin,” the Assam macaque, the penis of white-cheeked macaques is rounded, and their scrotum is dark and hairy. This distinction of genitalia helped convince wildlife researchers that they were looking at a new species. Prudence prevailed, thankfully, in giving these primates their common name of white-cheeked macaque.
Diet
These primates are known to forage in a wide range of habitats; however, no quantitative study of diet has yet been published for the white-cheeked macaque as of 2025. More is known about the diets of the four sympatric species of macaques that live in the region.
Rhesus macaques (M. mulatta) are omnivores and consume a large number of plants, roots, seeds, bark, and fruit along with insects, eggs, and chicks. The bulk of their diet, however, comes from human handouts and from raiding farm crops.
Tibetan macaques (M. thibetana) are omnivores with strong vegetarian tendencies. They prefer fruits and leaves, and sometimes eat bamboo or grass. Birds and snakes are on their menu only occasionally.
Assam macaques (M. assamensis) are omnivores who eat fruits, leaves, grasses, invertebrates, and grains (the last item is a testament to their skill as crop raiders).
Arunachal macaques (M. munzala) are largely herbivores (adhering to a mostly vegetarian diet), eating leaves, fruits, flowers, stems, and—during winter months—tree bark. They supplement their diet with the occasional small invertebrate and—for vital minerals including calcium, sodium, and iron—they eat mud. (The practice of eating mud, dirt, or clay is scientifically known as geophagy.)
So, what conclusions can be made, if any, about the diet of white-cheeked macaques? While the food preferences of the aforementioned sympatric species might suggest that the whiskered species share a common diet, certain factors must be considered. Do they prefer one plant to another or one part of a plant to another, having different plant preferences than white-cheeked macaques? These, and other, factors can play a role in shared food resources and in “neighborly” (or live-and-let-live) encounters between the species.
Certainly, Mêdog county offers a plethora of plant life—more than 3,000 species—from which white-cheeked macaques can make their dietary selections. Over 1,000 species of hexapods (six-legged arthropods) also live here, more than enough to supplement any monkey’s diet.
Since macaques are generally opportunistic omnivores, and since the region in which they live is rich in fruiting trees, dense vegetation, and abundant insect life, white-cheeked macaques are likely flexible feeders, relying mostly on fruits and plant matter but opportunistically consuming insects and other small animals when needed.
Behavior and Lifestyle
Little is known about the behavior and lifestyle of white-cheeked macaques. Because the region where they live had remained isolated for so long—it wasn’t until 2013 that a highway was built, linking Mêdog county with the rest of China and beyond—these elusive monkeys had managed to go undetected. With that being said, that highway paved the way to rapid change and development within Mêdog County. According to an article published in 2023, this new infrastructure cultivated a thriving tourism industry, as well as opened up many business opportunities for the locals. This also means that surveys can more readily be conducted in the region. Research is still ongoing, including new camera-trap studies that have begun to reveal more about group composition and daily patterns of the white-cheeked macaque.
Is it possible that, by looking at similar macaque species, we can gain clues or insights? Scientists have placed white-cheeked macaques in the sinica group, whose members include Assam macaques; Tibetan macaques (M. thibetana); toque macaques (M. sinica); and bonnet macaques (M. radiata). But some scientists dispute this placement, citing a specific anatomical difference: the white-cheeked macaque’s rounded penis. All other males in the sinica group are endowed with an arrow-shaped penis.
What we know for certain about white-cheeked macaques is from those two independent groups of intrepid explorers: the team of Chinese wildlife researchers, credited in 2015 with discovering the species, and the bird-watching group from India who affirmed the species’ discovery shortly thereafter.
Though regarded as an elusive species with minimal reported sightings, a recent camera-trap survey published in 2024 was able to capture 3,025 photographs of white-cheeked macaques, including 481 unique occurrences. Talk about paparazzi!
Wildlife researchers recognize at least 25 species of macaques. Except for Barbary macaques (Macaca sylvanus), who reside on the Rock of Gibraltar along North Africa’s Barbary coast, all of these species live in Asia.
White-cheeked macaques live in multi-male, multi-female groups (known as “troops”) comprising a pair of breeding adults and their young. In October 2013, the Chinese researchers encountered six groups of macaques over six days. Five of the groups were foraging or resting in the forest. Members of the sixth group, comprising two adult males and four adult females, were observed foraging along a riverbank. Eventually, a couple began to mate. Later in the day, researchers spotted (and photographed) two juveniles and another adult.
Fast forward to November 2014, when the Indian bird-watching group entered the forest in Arunachal Pradesh. To their delight, they encountered a family of six monkeys, yet to be identified as white-cheeked macaques. The monkeys, two males and four females, were grooming one another, resting, foraging, and playing along a riverbank. The birders’ patience rewarded them with an intimate moment: the adult couple began mating.
In reviewing extensive camera trap footage, the Chinese researchers noted that most images of these monkeys were captured between 12 p.m. and 7 p.m.; fewer were captured between 7 a.m. and 12 p.m.; and no white-cheeked macaques were photographed at night. These findings suggest a diurnal species, one that perhaps likes to sleep late.
Camera trap footage also captured white-cheeked macaques sitting upright on a bough of a tree, standing upright on the forest floor, moving quadrupedally (on all four limbs) along a riverbank, and sitting in a tree among thin branches, as if contemplating moving forward by grasping branch to branch. These behaviors suggest a species that is both terrestrial (land-dwelling) and arboreal (tree-dwelling). Sleeping sites have not been reported.
Adult white-cheeked macaques emit high-pitched alarm calls that carry a distance of 0.62–1.24 miles (1–2 km). The monkeys sound these urgent calls when frightened by human interlopers (or researchers, depending on the perspective of nonhuman primate vs. human primate). Having lived an isolated, natural life in the jungle for so long, white-cheeked macaques are not accustomed to human company.
Although their complete vocal repertoire has not been reported, all previously studied macaques share the following call types: alarm call, coo, growl, non-tonal scream, greeting call, tonal scream, squeak, food call, female and male copulation call, bark, and loud call.
Mutual grooming sessions appear to encompass a significant part of white-cheeked macaques’ days and are important in establishing familial bonds with one another.
Little data is available about the reproductive and family life of this still fairly newly discovered primate species. For clues, we might think to look at the Arunachal macaque, the white-cheeked macaque’s closest relative and a sympatric species. Alas, not a lot is known about the reproductive life of this primate, either. Inferences about the Arunachal macaque, first described in 2005, are drawn from closely related macaque species. We know that the gestation period (pregnancy) for other macaque species varies between 150 and 190 days. All macaques give birth to one or two offspring at a time, so this is likely true for white-cheeked macaques as well.
However, we can assume that the breeding season for white-cheeked macaques includes the months of October and November. Both the Chinese researchers and the Indian birdwatchers, respectively, witnessed a pair of adult white-cheeked macaques mating during these months. The winter season in Arunachal Pradesh is from October to March, so it’s likely that this is the breeding season for the species. Cooler winter temperatures, 41–59°F (5–15°C), are more amenable to getting cozy than the summer months (April to June) when 95°F (35°C) days are common. Monsoon season (July to September) may hold the least appeal for getting romantic. (We might also assume that these monkeys find a riverbank to be a romantic setting.)
Beyond calendar deductions and amateur, lighthearted scientific conjecture, only additional wildlife surveys will provide important insight into the reproductive life of white-cheeked macaques.
We do have some insight into family life. Camera trap images suggest that these monkeys take parenting seriously. Many photographs depict parents tending to their young. Mothers appear to show particular affection for their infants, whom they allow to clamber up mom’s body.
Assuming their diet is largely herbivorous, white-cheeked macaques disperse the seeds of the plants they have consumed via their feces, helping to regenerate new growth in their forested habitat. Apart from this integral ecological contribution, they are citizens of the earth in their own right.
The International Union for Conservation of Nature lists the white-cheeked macaque as Endangered (IUCN, 2021), appearing on the IUCN Red List of Threatened Species. Illegal hunting (poaching) and habitat loss due to the construction of hydropower stations in Mêdog are threatening the lives and futures of these monkeys. Of these two threats, the hydropower stations are the more ominous. Eighty-six percent of tree coverage in Anjaw, 1.4% in the Nyingtri area, and 4.9% in West Siang have been lost from 2001 to 2022, according to Global Forest Watch in 2022. It is assumed that this trend will continue to grow exponentially, especially with the continued cultivation of hydropower stations.
Macaques are known for raiding farm lands and eating the crops. This puts them at further risk of illegal hunting, as more than 50% of locals admitted in a survey that they would kill macaques to save their crops.
Conservationists fear that extensive tracts of riverfront forest (white-cheeked macaque habitat) will be flooded and forever lost; new roads have led to an influx in the human population and in human settlements, resulting in an increase in the bushmeat trade by providing hunters with easier access to the macaques.
Even the chief engineer for the geological survey team associated with the project has warned, “Tibet’s ecology is extremely vulnerable, and would be very hard to restore if damaged.”
White-cheeked macaques are listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
Fortunately, much more research has been conducted on the white-cheeked macaque in recent years, providing crucial insights for the conservation of this endangered species. For example, a 2024 study found that China’s current protected areas exclude over 94% of potential macaque habitats. The study also predicted that Southwest China will likely become a key refuge for many macaque species in the future and should therefore be prioritized for conservation efforts. It is important to continue to push for more research on this species in order to garner the information necessary to support its survival.
Wildlife researchers recognize the discovery of the white-cheeked macaque as an alarm call for the conservation of the species, along with the conservation and protection of other species (those already discovered and yet to be discovered) in this biodiverse region. They urge additional wildlife surveys and studies and call for environmental protection in southeastern Tibet.
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Written by Kathleen Downey, May 2020; Revised by Hannah Broadland, Oct 2025