Dent's mona monkey

Dent's mona monkey (Cercopithecus denti) is an Old World monkey in the family Cercopithecidae found in Central Africa. Debate on whether it constituted a separate species or subspecies continued between zoologists, and it was previously classified as a subspecies of other monkeys by some of them. It was re-classified as a separate species in 2001. It is classified as Least Concern in the IUCN Red List.

Dent's mona monkey
In Nyungwe National Park, Rwanda
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Suborder:	Haplorhini
Infraorder:	Simiiformes
Family:	Cercopithecidae
Genus:	Cercopithecus
Species:	C. denti
Binomial name
Cercopithecus denti Thomas, 1907
Synonyms
liebrechtsi Dubois and Matschie, 1912

Taxonomy

Dent's mona monkey is an Old World monkey in the family Cercopithecidae.^[2] The species was described by English zoologist Oldfield Thomas in 1907.^[3] Debate on whether it constituted a separate species or subspecies continued between zoologists. While many zoologists classified it as a separate species, it was classified as a subspecies of other species (mona monkey, Wolf's mona monkey, and crested mona monkey) by some of them across the years.^[2][4] Further research was required to examine the various species of mona monkeys in the forests between the Lualaba and Lomani rivers.^[4][5] It was re-classified as a separate species in 2001.^[6][7]

Morphology

It is a small monkey with long, flexible limbs, and a long tail. The males are larger with the females about two-third the size of the males.^[4] Males weigh about 3.8 to 4.2 kg (8.4 to 9.3 lb) and have a head to tail length of 44.5 to 51.1 cm (17.5 to 20.1 in) with a 49 cm (19 in) tail. The tail is mainly used for maintaining balance.^[7] Both the sexes exhibit similar colorization.^[4] The body fur varies in color from brown to red.^[7] The underside and inner part of the limbs are white in color.^[4][7] It has blue eyes with a tuft of hair extending from the brows towards the protruding ears.^[4] It has white facial hair above its lip. Dent's mona monkey has cheek pouches that are used to store food. It also possess thick skin on its hind quarters that supports prolonged sitting. The males have blue colored scrotums and larger canine teeth, as a part of sexual dimorphism.^[7]

Distribution and habitat

Dent's mona monkey is found in the Central African countries of Democratic Republic of the Congo, the Congo, Rwanda, western Uganda, and the Central African Republic.^[2][6] There have been reports of sightings in Burundi's Ruzizi plains. It prefers tropical forests of up to 2,400 m (7,900 ft) elevation in the eastern part of its range.^[7] It occurs in lowland river plains, and montane forests across the range.^[4] It is classified as Least Concern in the IUCN Red List.^[1]

Behavior

Dent's mona monkey is believed to have a life expectancy of about 20 years.^[7] It is diurnal and is most active in the early morning and in the evening.^[7] It is arboreal, spending most of the time in trees. It is omnivorous, and the diet ranges from fruits, flowers, and leaves to small insects.^[4][7] It generally moves on all four limbs.^[7] It makes loud and varied vocalizations. It is a social animal and is usually found in groups consisting of a single male and multiple females.^[4] Group sizes typically range from seven to twenty-one individuals, though these groups may occasionally divide into smaller units to forage more efficiently. Dent’s mona monkey is also known for its interspecies cooperation, often joining with other monkey species to search for food and remain alert to predators. In some cases, it has even hybridized with Doggett’s silver monkey.^[8]

Sexual behavior and reproduction

Dent's mona monkey follows a social structure in which one dominant male mates with multiple females; reproduction is largely driven by female behavior. When the male-to-female ratio is low within a group, outside male groups occasionally enter to compete for mating access. Reproduction is typically seasonal, with most births occurring between June and December, aligning with greater food availability, and the typical pregnancy lasts about five and a half months. Females generally give birth every two years, most often to a single baby, with twins being uncommon.^[8] Births usually occur overnight and high in the trees.^[9] Newborns are dependent on their mothers, often carried on their backs for several months, and may also receive care from other females within the group.^[8] Weaning typically happens by one year of age and reach reproductive maturity between two and five years old.^[9] Once mature, females stay in the group they were born into, while males disperse to live among other bachelor groups.^[8]

Communication

Dent's mona monkey relies on various methods of communication, including vocal, visual, and physical touch. Although generally quiet, it produces different types of calls for specific purposes. Short contact calls help individuals stay together while foraging, and distinct alarm calls alert others of danger. Males use loud territorial calls to announce their presence and dominance over an area. Nonverbal cues like posture and facial expressions convey signs of unease or hostility. Grooming is also a key part of interaction, strengthening social bonds while supporting hygiene. While not yet documented, chemical signaling through pheromones also plays a part in their communication.^[8]

Conservation status

Although the IUCN categorizes Dent's mona monkeys as a species of Least Concern, their populations face ongoing pressures from human activities such as deforestation, hunting, and mining expansion. While specific studies on their natural predators are limited, it is assumed they are vulnerable to the same carnivores and birds of prey that commonly target other African forest primates, which include leopards, golden cats, large snakes like pythons, and raptors such as crested eagles.^[9]