L'Hoest's Monkey is native to east central Africa around the east Congo Basin from Congo to west Uganda.
It has a mainly black body with white fur around the front neck and cheeks, but a greyish back with a red saddle like the Diana and Roloway Monkeys.
However, it is apparently not closely related to the Guenon's and may be moved from the Cercopithecus genus.
Like the Diana Monkey, L'Hoest lives in small, all female groups (plus mixed young) with a visiting adult male; other males are mainly solitary.
Babies initially have ginger-brown fur, darkening as they grow older.
L'Hoest's Monkey is endangered by deforestation and hunting for bushmeat.