The blue monkey is a forest-dwelling tree monkey. Adult females studied in Kenya's Kakamega Forest ate much fruit and shifted foods as availability changed.
Its back is grayish, its limbs are darker, and it has a pale band across the brow.
Among adult females studied in Kakamega Forest, fruit made up most of the diet. Young leaves served as a fallback when fruit was less available.
An extinction-risk assessment has not been added yet.