Collectively, Cercocebus and Mandrillus include nine species and two subspecies of African monkeys: seven species of Cercocebus and two of Mandrillus, including two drill subspecies. Together, they represent some of the least studied and hence least known of the Afro-Eurasian Primates.
Ranging from forests in Senegal to the Zanzibar Archipelago, red colobus monkeys (Piliocolobus spp.) are the most threatened group of African monkeys. According to the IUCN Red List of Threatened SpeciesTM in 2020, every form of red colobus monkey is threatened with extinction, and 14 of the 18 taxa (>75%) are listed as Critically Endangered or Endangered. Despite their conservation status, only a few populations have been studied in any detail and the general public is largely unaware of these monkeys and their plight.
