The Diana monkey is a peculiar species of primate who lives only in a very specific part of the world: on the western edge of Africa; Cerocopithecus Diana lives exclusively in the small region surrounding Sierra Leone and the Ivory Coast. These blackish or grey monkeys are classified as Vulnerable by the IUCN due to the destruction of their habitat which has lead to a decrease in population and natural range for the species. Not only is their habitat disappearing but unfortunately they are hunted by humans for bushmeat.

Active during the day only, Diana monkeys sleep in the trees by dark and spend their days making lots of noise, specifically alarm sounds to warn others of potential threats like Leopards or larger primates like chimpanzees. The west African monkey grows up to 21.5 inches (55 cm) in length and can weigh up to 15.5 pounds (7 kg). That fairly small size makes them vulnerable to attacks by even some of the smaller chimps. Perhaps because of all the dangers they rarely come down to the ground and prefer the treetops going even higher in the canopy when they are looking for a safe spot to sleep.

Diana monkeys have a white breast, their coloring typically runs all the way up under the jaw and to the ears, like a large white “beard”. With an average lifespan of about 20 years, their distinctive white beard makes them look markedly older. They aren’t elderly however, they just prefer to wear their beards that way.

Though their vocalizations can be very loud and annoying to people, some of the other denizens of the forests in which the Diana monkey lives can distinguish between their unique calls, and have been observed heeding the warnings of the Diana monkeys in an attempt to evade the same predators who threaten them both.

The Roloway and Dryas monkeys look similar and were once classified as subspieces of the Diana but are not considered their own species.