Why these Old World monkeys are the most successful colonizers after humans

Nature · Published 3 October 2026 Swipe more like this →

In short: Cercopithecinae are a remarkably adaptable subfamily of Old World monkeys, thriving in environments ranging from tropical rain forests to snowy mountains. With roughly 71 species, including baboons and macaques, these primates have evolved specialized physical traits and social structures that allow them to dominate diverse habitats across Africa and Asia.

The subfamily Cercopithecinae represents an evolutionary success story, second only to humans in their ability to colonize non-arboreal landscapes. This group, which includes well-known primates like baboons, macaques, and guenons, is defined by specific anatomical features. They possess narrow noses with downward-facing nostrils and ischial callosities—often called sitting pads—on their rumps. In some species, these pads even change color during mating cycles, serving as a visual signal within their complex social groups.

Adaptation is the hallmark of the cercopithecine lineage. Their physical form is dictated by their environment: arboreal species tend to be slender and delicate with long tails, while terrestrial counterparts are stockier, sometimes possessing reduced or nonexistent tails. Regardless of their terrain, all members of the subfamily share well-developed thumbs and unique cheek pouches, which function as biological storage units for food. This allows them to forage efficiently for a varied omnivorous diet that includes fruits, seeds, insects, and even small vertebrates.

Socially and biologically, these monkeys are highly resilient. They are diurnal creatures that live in groups across climates as varied as the savannah, rocky outcrops, and freezing mountain ranges. Their reproductive cycle is relatively steady, with a gestation period of six to seven months and maturation occurring within three to five years. With some species living up to 50 years, these primates have established themselves as one of the most widespread and enduring groups of mammals in the Old World, demonstrating a versatility that few other non-human primates can match.

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