Despite its name, the blue monkey is not noticeably blue: it has little hair on its face, and this does sometimes give a blue appearance, but it never has the vivid blue appearance of a mandrill, for example. It is mainly olive or grey apart from the face (which is dark with a pale or yellowish patch on the forehead - the "diadem" from which the species derives its common name), the blackish cap, feet and front legs, and the mantle, which is brown, olive or grey depending on the subspecies. Typical sizes range from 50 to 65 cm in length, (not including the tail, which is almost as long as the rest of the animal), with females weighing a little over 4 kg and males up to 8 kg. Alloparenting is common among blue monkeys. The most common infant handlers are juvenile females and usually one infant is carried by a number of alloparents. One hypothesis is that this allows the infant to learn to socialise at an early stage in life. Learn more about Blue Monkey