Old World Monkeys

Abstract

Abstract Old World monkeys, or cercopithecoids, are a diverse and widespread group of primates found throughout Africa and Asia. They are characterised by their specialised molar teeth, quadrupedal running behaviour, often spending more time on the ground than other primates, as well as their often large and complex social groups. They survive in the widest range of habitats of any nonhuman primates, with some species restricted to humid tropical forests whereas others are found in mountains and deserts. There are two main groups: the cercopithecines, which have cheek‐pouches and include macaques, baboons, mangabeys, vervets and guenons; and the colobines, characterised by complex stomach anatomy that allows them to digest leaves and which include langurs, proboscis monkeys, doucs and snub‐nosed monkeys and colobus monkeys. Although they are termed ‘monkeys’ they are more closely related to apes and humans (hominoids) than they are to the monkeys of Central and South America. Key Concepts: As they are large, occur in large social groups, are often terrestrial and active during the day, Old World monkeys are some of the most thoroughly studied wild primates. Groups of closely related females, called matrilines, usually form the core of Old World monkey social groups because females remain in the same group as their mothers, whereas males generally transfer to a new group when they become adults. Old World monkeys are the most diverse group of primates in terms of environmental and geographic range, as well as number of species, but have achieved this diversity through relatively narrow morphological and behavioural adaptations that allow for ecological flexibility. Compared to other primate groups, Old World monkeys are a recent adaptive radiation, which may in part explain their relative lack of anatomical diversity, and they seem to have replaced the apes as the predominant primates in Africa and Eurasia as climatic change made environments more open and seasonal.