- Latin Name: Cercopithecus pogonias
- Bioko's Subspecies: Cercopithecus pogonias pogonias
- IUCN Status: Vulnerable
- Captive Population: 18 at the species level, but none of the subspecies, according to ISIS.
The crowned guenon is a relatively small, arboreal monkey with a long tail, grizzled sides and hindlegs and black outer arms and feet. The very prominent, pointed ears are yellow and the underside is orange, yellow or white. A striped crest runs along the center of its head.
On Bioko Island this agile, vocal monkey lives in diffuse groups of approximately 8 to 10 with a single dominant male. The male's "boom" call ( a series of two or three "ooo" vocalizations, given approximately 5 seconds apart, that sound like blowing over the top of a Coke bottle) rallies group members after dispersal or a disturbance. Adult male crowned guenons use hacks (like Bioko's other cercopithecine monkeys) to indicate alarm. Although sometimes difficult to distinguish from other species, the crowned guenon hack is typically a 3 syllable vocalization, "Ek-uh-eh" (and the equivalent red-eared guenon "hack" has 2 syllables, "Ek-eh"). The alarm "chirps" of female crowned guenons are difficult to distinguish from those of other cercopithecines on Bioko Island. However, females and young crowned guenons use a distinctive "whine" contact vocalization. The crowned guenon diet is roughly 80% fruits and 20% invertebrates.
One of the two smallest Bioko Island monkeys, the crowned guenon has a limited distribution on the southern slopes of the Gran Caldera and Southern Highlands Scientific Reserve. Recently it has become increasingly common near Moka, and now may be the only monkey species on Bioko Island that is actually expanding its range. There used to be a small population on the southern slopes of Pico Basile as well, but those animals were probably hunted out in 2000. This species has a wide range on mainland Africa, making it less threatened than many of the other Bioko Island monkeys.
The crowned guenon was the first monkey described to science from Bioko Island, by Bennett at a meeting of the Zoological Society of London in 1833.
Cronin, D. T., D. Bocuma Meñe, T. B. Butynski, J. M. E. Echube, G. W. Hearn, S. Honarvar, J. R. Owens, and C. P. Bohome. 2010. Opportunities Lost: The Rapidly Deteriorating Conservation Status of the Monkeys on Bioko Island, Equatorial Guinea (2010). A Report to the Government of Equatorial Guinea by the Bioko Biodiversity Protection Program, Drexel University, Philadelphia, PA. 40pp.