The Olive baboon is the most wide ranging of all baboons, being found in savannahs, steppes, and forests of 25 countries throughout Africa, extending from Mali eastward to Ethiopia and Tanzania. Omnivorous, they are able to find nutrition in almost any environment, and are able to adapt with different foraging tactics. They eat a large variety of plants (such as leaves, grass, roots, bark, flowers, fruit, lichens, tubers, seeds, mushrooms, corms, and rhizomes), and invertebrates and small mammals, as well as birds. In dry, arid regions, such as the northeastern deserts, they hunt small invertebrates like insects, spiders, and scorpions and elsewhere larger animals such as small rodents and hares to foxes and other primates. Its limit is usually small antelope, such as Thomson's gazelle and also, rarely, sheep, goats, and live chickens, which may amount to 33.5% of its food from hunting. In Eritrea, the olive baboon has formed a symbiotic relationship with that country's endangered elephant population. The baboons use the water holes dug by the elephants, while the elephants use the tree-top baboons as an early warning system. They live in groups of 15 to 150, made up of a few males, many females, and their young. Each baboon has a social ranking somewhere in the group, and female dominance is hereditary, with daughters having nearly the same rank as their mothers. Despite being hierarchical, baboons appear to be democratic when it comes to deciding the direction of collective movement. Individuals are more likely to follow when multiple decision-makers agree on what direction to go rather than simply following dominant individuals. The male olive baboon is on average, 70 cm tall while standing and 24 kg while the female measures 60 cm in height and averages 14.7 kg and they both have a green-grey coat. Like other baboons, they have an elongated, dog-like muzzle. Their tail almost looks as if it is broken, and they have a bare patch on their rump and a cheek pouch in which to store food. They communicate with various vocalizations and facial expressions. Adults give a range of calls and the most common facial expression of the olive baboon is "lipsmacking", which is associated with a number of behaviors. They are listed as least concern because they are "very widespread and abundant and although persecuted as a crop raider there are no major threats believed to be resulting in a range-wide population decline." Despite persecution, the baboon is still widespread and numerous. However, competition and disease have possibly led to fewer baboons in closed forests.