The Grey's crowned guenon ("Cercopithecus pogonias grayi"), also known as the crowned guenon, crowned monkey, golden-bellied guenon, or golden-bellied monkey, is a species of monkey. They are mainly found in Central Africa which includes countries like Angola, Cameroon, Central African Republic, Republic of the Congo, Democratic Republic of the Congo, Equatorial Guinea, Gabon, and Nigeria. Mona monkeys get up to in length and weigh . The lifespan of the crowned guenon is 20 years in captivity. They feed on mostly fruit, leaves, shoots, insects, and crops.