The L’Hoest’s monkey, scientifically known as Allochrocebus lhoesti, is a distinctive primate residing in the mountainous forest regions of Central Africa. Sometimes called the mountain monkey, it offers a unique glimpse into the diverse primate life of the African continent.
Identifying Features
The L’Hoest’s monkey has a short, dark coat with a reddish-brown, saddle-shaped patch on its back. A prominent white beard or bib extends from its throat to its ears, framing a dark face with light gray cheeks and a pale mustache. They have bright orange eyes.
These primates have long limbs and a tail up to 39 inches long. Both sexes share similar coloration, but males are larger, weighing about 13.2 pounds compared to females at 7.7 pounds. A distinctive feature in males is their bright blue scrotum, with the intensity of the color potentially indicating dominance.
Where They Live and What They Eat
L’Hoest’s monkeys are found in eastern Democratic Republic of Congo (DRC), Rwanda, Burundi, and western Uganda, primarily in the Albertine Rift. They thrive in various forest types, including lowland, submontane, and montane tropical forests, at elevations between 2,952 and 8,202 feet. They also inhabit regenerating forest areas and cultivated lands, foraging for food.
Their diet is omnivorous. They primarily consume terrestrial herbs, fruits, mushrooms, and leaves; fruits are a significant part of their intake. They also eat invertebrates like insects, earthworms, and spiders, and occasionally small vertebrates such as lizards and birds. They forage in both the lower and upper forest levels.
Group Life and Unique Behaviors
L’Hoest’s monkeys live in small, female-dominated groups of 10 to 17 females and their offspring, led by a single male. Females within a group are often related, forming strong bonds through mutual grooming and allomothering, where multiple females help raise the young. Other males may form separate “bachelor” groups.
These monkeys are diurnal, most active in early morning and late afternoon. Although skilled climbers, they spend much time foraging and traveling on the ground, a semi-terrestrial habit unusual for guenons. When threatened by ground predators, they typically flee to trees and become very still. They use various alarm calls, with distinct sounds for different dangers. Adult males make loud, distinctive calls and use visual displays, such as staring with raised eyebrows and an open mouth without showing teeth, for threat displays.
Protecting the Species
The L’Hoest’s monkey is classified as Vulnerable by the International Union for Conservation of Nature (IUCN). Their populations have declined, and this trend is projected to continue. Habitat loss is a primary threat, driven by deforestation for agricultural expansion and artisanal mining.
Hunting for bushmeat also poses a danger, with L’Hoest’s monkeys being particularly susceptible to snares and shotguns. Political instability in their range complicates conservation. They inhabit several protected national parks, including Virunga and Kahuzi-Biega in the DRC, Nyungwe in Rwanda, and Bwindi Impenetrable in Uganda. These areas provide refuges, but ongoing efforts are needed to control illegal hunting and mitigate habitat degradation.