Diana monkey

There is no mythological or supernatural origin for the Diana monkey in the supplied material. The English common name originates in a European naturalist analogy: the species' distinctive white, crescent-shaped browband was said to resemble the crescent associated with the Roman goddess Diana, and this visual resemblance led to the English name. The provided sources do not supply indigenous West African names or cosmogonic narratives for the animal.

Adults measure roughly 40–55 cm in body length (excluding the tail), with tails around 50–75 cm, and weigh approximately 4–7 kg; healthy individuals may live up to about 20 years. The pelage is generally dark (black or dark grey) with striking white facial and throat markings: a crescent-shaped white browband, white throat, ruff and beard, white underarms, and a white stripe down the thighs; the backs of the thighs and lower back are chestnut-coloured and some fringes on the limbs are present. The fur has been described in sources as "rough and tough." The crescent browband is the species' most distinctive feature and is explicitly cited as the trait that inspired the common English name.

The Diana monkey is a diurnal, arboreal primate that forages at all canopy levels and rarely descends to the ground, sleeping on upper branches without building nests. Its diet is primarily frugivorous and folivorous (fruit, blossoms, leaves), supplemented occasionally by insects and other invertebrates. Socially, groups typically consist of a single adult male, multiple reproducing females and their infants; daughters commonly remain in natal groups while males disperse before sexual maturity. Reproduction involves a gestation of roughly five months, nursing for about six months, and sexual maturity around three years. The species is vocally active: females produce distinct alarm calls, alert calls, and contact/greeting calls, and their alarm calls can be predator-specific and are used by other forest species (for example, yellow-casqued hornbills and other birds) as referential signals. Predators recorded in the sources include the crowned hawk-eagle, African leopard, common chimpanzee, and humans. The species has been the subject of primatological research into referential labelling and attention in conspecifics.