The most widespread baboon, found across 25 equatorial African countries from Mali to Ethiopia and Tanzania. Named for their olive-green pelage (a mix of yellowish and black banded hairs). Males are large (22–37 kg) with prominent canine teeth and a heavy mane; females weigh 12–18 kg. They have a long, dog-like muzzle and powerful jaws. Olive baboons are among the most adaptable primates, occupying savannas, woodland, grassland, and even arid regions. They are omnivorous and opportunistic, eating grasses, roots, fruits, insects, small vertebrates, and occasionally hunting young gazelles. Social structure is multi-male, multi-female troops of 15–150 individuals with complex dominance hierarchies, coalitions, and friendships between males and females. They are terrestrial and diurnal, sleeping in trees or on cliffs at night. Gestation is ~180 days. They are used in behavioral ecology and biomedical research (cardiovascular disease, stress physiology). Lifespan is 25–30 years. They can be significant crop-raiders. IUCN: Least Concern.