The white-cheeked macaque (''Macaca leucogenys'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

macaque The macaques () constitute a genus (''Macaca'') of gregarious Old World monkeys of the subfamily Cercopithecinae. The 23 species of macaques inhabit ranges throughout Asia, North Africa, and (in one instance) Gibraltar. Macaques are principally ...

found only in

Mêdog County Mêdog, or Metok, or Motuo County (; ), also known as Pemako ( meaning "Lotus Array", ), is a county as well as a traditional region of the prefecture-level city of Nyingchi in the Tibet Autonomous Region of the China, People's Republic of Chin ...

in southeastern

Tibet Tibet (; ''Böd''; ) is a region in East Asia, covering much of the Tibetan Plateau and spanning about . It is the traditional homeland of the Tibetan people. Also resident on the plateau are some other ethnic groups such as Monpa people, ...

and

Arunachal Pradesh Arunachal Pradesh (, ) is a state in Northeastern India. It was formed from the erstwhile North-East Frontier Agency (NEFA) region, and became a state on 20 February 1987. It borders the states of Assam and Nagaland to the south. It shares int ...

in northeastern

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

. The white-cheeked macaque lives in

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s, from

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

forests to primary and secondary

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

broad-leaved forests and mixed broadleaf-

conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...

forests. The species was first described by Chinese

primatologists Primatology is the scientific study of primates. It is a diverse discipline at the boundary between mammalogy and anthropology, and researchers can be found in academic departments of anatomy, anthropology, biology, medicine, psychology, vete ...

Cheng Li, Chao Zhao, and Peng-Fei Fan, in the ''

American Journal of Primatology The ''American Journal of Primatology'' is a monthly peer-reviewed scientific journal and the official journal of the American Society of Primatologists. It was established in 1981 and covers all areas of primatology, including the behavioral ecol ...

'' in 2015. It is one of twenty-three

extant Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, ...

species in the genus ''Macaca'', and the most recent to be formally described to science. While the species' exact

conservation status The conservation status of a group of organisms (for instance, a species) indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation ...

has not yet been determined, it is likely threatened by

poaching Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set a ...

deforestation Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated d ...

, and increased human development of its habitat, much like the other primates which inhabit the area.

Discovery

White-cheeked Macaque Walong Arunachal Pradesh India November 2019

The white-cheeked macaque was discovered and described in 2015. While specimens of the creature had been observed and known for many years prior, they were believed to be members of the species ''Macaca assamensis'', the

Assam macaque The Assam macaque (''Macaca assamensis'') or Assamese macaque is a macaque of the Old World monkey family native to South and Southeast Asia. Since 2008, it has been listed as Near Threatened on the IUCN Red List, as it is experiencing significan ...

. After footage captured on a series

camera trap A camera trap is a camera that is automatically triggered by a change in some activity in its vicinity, like presence of an animal or a human being. It is typically equipped with a motion sensor – usually a passive infrared (PIR) sensor ...

s in

revealed numerous physical differences between the Assam macaque and the animals caught on tape (including more prominent

whiskers Vibrissae (; singular: vibrissa; ), more generally called Whiskers, are a type of stiff, functional hair used by mammals to touch, sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are c ...

, thicker neck

hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and f ...

, and differences in the shape of the

genitalia A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...

in China declared them to be a new species. Their research, along with a series of photographs of the species, was published in the July 2015 issue of the ''American Journal of Primatology''. In April 2016, a group of wildlife photographers and biologists spotted and photographed the white-cheeked macaque in

. Prior to this sighting, the species was thought to exist only in Tibet.

Appearance

Physiologically Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...

, the white-cheeked macaque is similar to the other members of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Macaca''. It is

robust Robustness is the property of being strong and healthy in constitution. When it is transposed into a system, it refers to the ability of tolerating perturbations that might affect the system’s functional body. In the same line ''robustness'' ca ...

and has a short tail. In terms of outward appearance, it closely resembles the Assam macaque, which is one of the reasons the two were believed to be the same species until recently. The main differences between the two include the presence of white, elongated whiskers on the face of the white-cheeked macaque, which are absent from other species. The whiskers begin to grow as the creatures approach

sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definitio ...

, and eventually cover the whole face, giving the animals a rounded facial appearance. The white-cheeked macaque also grows dense hair along its neck, while not growing any hair along its short

tail The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...

. Additionally, there is a distinct difference in the shapes of the genitalia of the two species; contrary to the arrow-shaped structure present in the Assam macaque, the white-cheeked macaque displays a more rounded structure. This was one of the main characteristics that allowed scientists to realize they were dealing with a new species.

Ecology

The white-cheeked macaque has been observed in tropical forests at an altitude of 1395 meters, primary and secondary evergreen broad-leaved forest up to 2420 meters and mixed broadleaf-conifer forests of 2700 meters. The forests in Mêdog, Tibet are protected by

Yarlung Zangbo Grand Canyon The Yarlung Tsangpo Grand Canyon, also known as the Yarlung Zangbo Grand Canyon, the Tsangpo Canyon, the Brahmaputra Canyon or the Tsangpo Gorge ('), is a canyon along the Yarlung Tsangpo River in Tibet Autonomous Region, China. It is the deep ...

Nature Reserve. It is thought they live in small multi-male multi-female groups. When the white-cheeked macaque detects the presence of humans it emits a loud high pitched alarm call, flees, and climbs trees. This call is distinct in frequency from the Assam macaque.

References

{{Taxonbar, from=Q19800858 Macaca Primates of Asia Mammals of India Fauna of Tibet Fauna of Arunachal Pradesh Mammals described in 2015