Diademed monkey, Golden monkey, Samango, Sykes' monkey
Despite what the common name suggests, the Blue monkey is not blue. In fact, the species is so called due to the hairless face, which seems to be colored in blue. This Old world monkey is of great interest for scientists. The primate has a dark head top. The coloration of the body is mainly olive or grey. Additionally, the Blue monkey exhibits some black and white markings all over its body.
The Blue monkeys have a rather large natural range, covering central, eastern, and southern Africa as well as the Congo basin. Within this range, Blue monkeys inhabit humid and shady areas. Constant source of water is among the primary required conditions. Overall, preferred habitats are evergreen forest, forest canopy and bamboo forest.
Blue monkeys are diurnal animals that are active during the daytime hours. They are highly social creatures, forming groups of 10 - 40 individuals. This is a female-dominated society, consisting of a single male and multiple females with their young. This kind of social structure prevents interbreeding within the group. When reaching maturity, females continue living with their natal groups, whereas males have to leave in order to join another group. However, sometimes it takes too long for them to find a group, hence some of these males may live solitarily. Blue monkeys are arboreal animals, living in trees. Group members spend a lot of their active time playing and grooming. These primates are known to be highly territorial. If an individual wants to join a given group, it has to challenge and overcome the dominant male of the group.
Blue monkeys are generally polygynous, which means that one male mates with numerous females. However, this species also exhibits polygynandrous (promiscuous) mating system, where individuals of both sexes have multiple mates. Although they breed year-round, females yield offspring every two years. A single infant is born after a gestation of 5 months. Babies are usually born with intervals of a few days. Newborn young live in groups of up to 40 individuals, where females care for each other's young. Weaning occurs at 6 months old and the age of sexual maturity is 3 years old.
The biggest threat to the population of these primates is destruction of their natural habitat as a result of rainforest clearing. Additionally, Blue monkeys are hunted for meat. These animals are also persecuted as pests due to consuming cultivated crops or destroying non-native trees.
According to IUCN, Blue monkey is generally common throughout its range but no overall population estimate is available. However, there have been estimated 200-500 individuals of the Blue monkey subspecies, living in Somalia. Overall, Blue monkeys are classified as Least Concern (LC), but their numbers are decreasing today.
On one hand, Blue monkeys are an important prey species for various predators of their range. On the other hand, as frugivorous animals, they act as key seed dispersers of many local plants.