Olive Baboon, Papio anubis
OLIVE BABOON
Papio anubis
Geographic Distribution and Habitat
Found across 25 countries throughout equatorial Africa, the olive baboon (Papio anubis)—also referred to as the savanna monkey or Anubis baboon—has the most expansive range of any baboon species. Whether they are perched atop a steep, jagged slope overlooking sunlit grassy plains, or scurrying on all fours across semi-desert landscapes, olive baboons have established a formidable presence throughout the sub-Saharan region of the continent. These hardy and adaptive primates inhabit savannas, tropical evergreen forests, semi-deserts, steppes, montane forests, semi-arid woodlands, and even areas near human settlements. From the Ethiopian riverbeds of the Bole Valley to the open woodlands of Uganda, so long as there is a water source nearby, olive baboons are able to call it home.
Troops have been recorded in Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Congo, The Democratic Republic of the Congo, Côte d’Ivoire, Eritrea, Ethiopia, Ghana, Guine, Kenya,Mali, Mauritania, Niger, Nigeria, Rwanda, Sierra Leone, Somalia, South Sudan, Sudan, Tanzania, United Republic of Togo, and Uganda. At one point, an isolated population lived in Spain until they were captured and placed into captivity.
Hybrid zones can be found within the olive baboons’ extensive range of species, where various species mix and reproduce. These zones are present where olive baboons intersect with hamadryas baboons and yellow baboons.
Size, Weight, and Lifespan
Olive baboons are sexually dimorphic; males have a size advantage nearly double that of females. Average male height is roughly 2.3 feet (70.1 cm), with females coming in around about 2 feet (60 cm) tall. The average wild male weighs 53 pounds (24 kg), females 32.4 pounds (14.7 kg). However, weight can fluctuate based on habitat and diet. Populations that have crop-heavy diets are slightly heavier, perhaps due to the carbohydrates and garbage (literally garbage!) they consume; males average 60.4 pounds (27.4 kg) and females 34.4 pounds (15.6 kg). Captive olive baboons are the largest, with males weighing roughly 64 pounds (28.9 kg) and females 37.5 pounds (17 kg)
In the wild, individuals can live for 25-30 years; however, due to disease and injuries, few reach their full lifespan. In captivity, the oldest individual lived to 48 years old.
Appearance
Named for their pelage, olive baboons have shaggy black and yellow coats that appear greenish-gray from a distance. Males sport a long mane that drapes over their shoulders and along their backs. Their dark, charcoal faces are surrounded by coarse, gray hair. Olive baboons are known for their long dog-like muzzles equipped with powerful jaws and pointy canine teeth, which often yellow with age. They have deep-set amber eyes shielded by a heavy brow and specialized cheek pouches to store food during foraging. Their rumps are hairless and form ischial callosities, which are thickened layers of skin that act as sitting pads to allow them to sit comfortably on tree branches. Tails are naturally bent at a severe downward angle, often described as looking “broken”.
Infants are born with black fur and pink faces. It takes a year for their pelage and skin to change into that of an adult.
Diet
Olive baboons are opportunistic omnivores. Their flexible foraging habits allow them to inhabit diverse biomes. As a result, their diets are based on seasonality, location, and availability. Vegetation, depending on locations, includes grasses, roots, tubers, corms, leaves, exudates, cacti, mushrooms, as well as fruits, flowers, buds, seeds, and bark. Olive baboons will search high and low for their nutrient sources—through lush tree canopies, dense thickets, flowing fields of grass, and semi-desert landscapes. Troops that live near forests feast on a heavy fruit-based diet, while those near the savannas primarily fill up with seeds and grasses. During the dry season, many populations will use their dexterous fingers to dig up roots, tubers, and corms (a type of tuber found underground) to supplement food scarcity.
We mentioned olive baboons are omnivores—insects, scorpions, spiders, birds, and eggs are also an important part of their cuisine. However, this is only a short list of the animals they eat. Olive baboons are both scavengers and hunters. Both males and females utilize “simple” and “complex” hunting strategies to bring down prey such as small birds, rabbits, foxes, rodents, lizards, other primates, impalas, dik-diks, and gazelles. The most common strategy is “simple” hunting, which occurs when a single individual stalks their prey for less than 10 minutes within close range, usually to track something small and easy to catch. “Complex” hunting, which has specifically been observed in Gilgil, Kenya, is categorized by larger group participation, longer pursuits, and greater distances covered—this is usually for larger prey sources.
As agriculture and human settlements close in around olive baboon habitats, these cunning primates make good use of their evolving surroundings—despite the enemies they make along the way. Olive baboons are known to raid farmland and are considered vermin, plundering crops (such as maize, bananas, sugarcane, and beans) intended for their human cousins or livestock. They have also been known to eat trash or kill goats and sheep, all of which elevate human-wildlife conflict.
Behavior and Lifestyle
A diurnal species, olive baboons are active during the day and sleep at night. Their activity budget consists of mostly traveling and foraging, which takes up more than half of their day. Predominantly quadrupedal and terrestrial (but at times, bipedal), troops spend their time traveling in large troops. When they travel at a slower pace, they distribute their weight to walk primarily on their fingers and toes; for quicker speeds, they bear more weight on their palms and bottoms of their feet. They may scale trees to scan for danger or to procure certain foods. Here they climb, leap, and suspend from tree branches. Intermittent rest periods occur depending on food availability or distance traveled (usually 1 to 2 miles). At night, they retreat to rocky cliffs or trees to avoid predation.
Olive baboons are hierarchical and have complex social relationships. Males are protective and are in constant competition with one another to ascend rank, which changes throughout their lifetime. However, they also rely upon the wise females who have spent the duration of their lives within the same troop. It is their job to keep the peace and lead their families to food. Friendships, tight-knit family groups, and age all dictate different behaviors and interactions throughout their lifespans.
The scientific name—Papio anubis—comes from the olive baboon’s striking similarity to the Egyptian god, Anubis. Anubis had the face of a dog with a long snout.
In Nigeria, olive baboon populations are known to swim and dive underwater, which is unusual for many primate species.
Olive baboons live in sympatry with elephants in Eritrea, Africa. The two species reportedly have a symbiotic relationship. The elephants share their watering holes with the baboons in exchange for the primates acting as an alarm system, keeping lookout in the treetops for predators and threats.
Olive baboons typically live in multimale-multifemale troops of 15-150 members. Days begin with the adults sunbathing while youngsters play and socialize. From that point on, groups descend from their sleeping sites to begin foraging. They use an array of calls and barks to keep track of one another as they traverse the ground. Foraging continues until sundown when troops then clamber back to their sleeping quarters and spend time socializing and grooming before bed. Grooming is a critical social component for olive baboons; it cultivates bonds, nurtures existing relationships, promotes health, and can even act as a calming ritual between individuals.
When it comes to sleep, one may wager that baboons opt for protection over comfort. At night, they prefer to rest upon barren rocky cliffs with steep slopes to avoid predation. For a baboon, the less vegetation, the better. Bare, rocky walls are difficult for predators with paws and claws to scale, allowing them to have a safe night’s rest. If a cozy cliff isn’t available, troops will congregate in trees with wide tree trunks. Males stay closest to the base of the trunk to protect the females and young who sleep farther away.
Female rank is inherited from mother to daughter, as they almost always remain with their natal family groups, and dominance helps dictate food and reproductive accessibility. Within a troop, matrilineal lines have their own hierarchy. Females maintain and strengthen their social bonds through grooming and remaining within proximity of their family members during resting periods.
Males leave their natal groups upon maturation between the age of 6-9 years old. Throughout their lifetime, they join and depart from a troop every few years, which helps to prevent breeding with their offspring. When approaching a new group, they tend to be curious and friendly, trying to connect with females first, as well as other vagabond males without rank. Once comfortable, they then try to challenge more dominant males which can be highly competitive and aggressive. Fighting can occur daily, although this is not a permanent behavior. Males also conduct ritualized greetings in neutral situations and can amicably acknowledge ranks when there isn’t resource competition. After they surpass their prime, males enjoy their golden years in a more relaxed manner and form coalitions with one another, often to protect females in estrous from rambunctious young males. (Female mating does not always directly correlate with rank; sometimes, they prefer friends or older males that they are comfortable with and have been in the same group for quite some time).
Additionally, females and males often form friendships with one another, where they spend exclusive time grooming, traveling, foraging, and sleeping near one another.
As a social species, olive baboons utilize vocalizations, facial expressions, and gestures to communicate.
A basic grunt is the most common vocalization used by all ages throughout many social situations. Barks, roars, screeches, humming, panting, and screams are also used to express a wide range of emotions. Infants and juveniles use moans, chirps, clicks, and gecks when they are displeased, frightened, or separated from their mothers. During playtime, they pant, which is often described as sounding like breathy laughter.
Olive baboons also use contact calls when foraging to keep track of their family members. When displaced, olive baboons exchange “wa-hoo” calls; this may be a response to predators, a lost group member, or other times of distress. A “wa-hoo” call can also be used in male-male conflicts or as a nighttime chorus before they retire.
When danger is imminent, olive baboons will emit an alarm call—a series of shrill barks—to encourage others to flee from an area.
In neutral situations, male baboons will conduct ritual greetings, approaching each other with a swift gait, ears pressed back, lips smacking. They may also fondle genitalia. This is a way to remind one another of rank without confrontation. Reciprocation acknowledges rank while turning away rejects it.
If an olive baboon yawns, stares, raises their eyebrows, exhibits a penile display, or grinds their teeth, it is a warning not to be taken lightly. Yawning, staring, and hitting the ground are forms of aggression. Head bobbing, the stiffening of arms, and slapping are also responses to threats.
Head shaking, jaw clapping, the narrowing of eyes, flattening of ears, and even sticking out their tongues are some of their communicative facial expressions. Tongue smacking is a versatile display that may convey appeasement, reassurance, and submission. It is often used during grooming and reproduction. Quick glancing is used to diffuse tension. Tail extension, fear grins, and rigid crouching are also submissive behaviors.
Sexual maturity occurs between the ages of 4-6, but fully grown adulthood is not reached until 7-10 years. When in estrus, a female’s genital regions swells and turns bright pink to indicate to males she is ready to mate. Some studies show the more inflated a backside, the more appealing she is to a male. However, this is a sensitive period for females, as it can be uncomfortable and easier for the skin to tear, making her susceptible to bacteria and infection. Males tend to prefer breeding with seasoned mothers for reproductive success. A high-ranking female may give birth more frequently than low-ranking females.
Breeding occurs year-round, and males and females are known to take multiple mates. A male and female engage in consortship, which is a temporary relationship where they copulate, groom, and spend time with one another during estrus. A female male may have several consortships during a single cycle, and often has a posse of up to 8 males following her and her partner.
Once impregnated, gestation lasts for 180-185 days. Babies are born helpless and depend on their mothers to rear them in the beginning. Like humans, sleeping and feeding is practically all they do. One of the first things an infant learns is how to grasp, a key skill that allows them to cling to their mothers and remain close as they travel and feed. As the weeks wear on, youngsters ride on their mother’s backs. They become more independent and curious, often lolling away from mom. They do not venture far for the first few months, and mothers are always quick to scoop them back if they feel like they are separated for too long. Their protective maternal instincts are very strong. Other females in the group will also help care for infants.
Babies are weaned after 10-12 months. At this point, activity and play become increasingly important and both males and females act as caretakers. Males may babysit to allow females to forage, participate in grooming, and offer protection while demonstrating group interactions that the youngsters will carry into their adulthoods. This is especially important for other young males to observe before they leave their troop and find their own one day.
Olive baboons are credited as vital seed dispersers for their ecosystems. Given their wide territory range, they are exposed to a variety of plants. In northeastern Ivory Coast, a prominent savanna forest, olive baboons consume up to 79 plant species. Any intact seeds from their fecal matter have the potential to grow into new specimens. As subterranean browsers, they also aerate the soil when they forage for corms, tubers, and roots.
Predators of the olive baboon include lions, leopards, servals, wild dogs, hyenas, chimpanzees, crocodiles, and domestic dogs. Small youngsters are specifically susceptible to raptors.
The International Union for Conservation of Nature lists the olive baboon as Least Concern (IUCN, 2020), appearing on the IUCN Red List of Threatened Species.
Current data suggests that their numbers are substantial, and the population is quite stable. However, this does not mean there isn’t severe human-wildlife conflict. Under the African Convention, they are listed as Vermin, and thousands are killed each year by farmers and hunters in communities. In Ethiopia, surveys reported that olive baboons are the second biggest threat to agriculture. Locals will use domestic dogs and enforce land guarding to keep olive baboons at bay, which includes shooting, trapping, and even poisoning.
In certain areas in Nigeria, olive baboons are hunted for bushmeat—males, in particular, are sought due to the high levels of protein their meat provides—although this is rather isolated and local to the region. High risks are associated with the consumption of olive baboons as they carry Simian Immunodeficiency Viruses (SIV), the Ebola virus, and a bacterium closely related to syphilis.
Despite their present sustainable numbers, researchers urge continued observation of olive baboons. Human population growth, habitat loss, and disease transmission have the potential to turn into serious threats and impact their conservation status.
The olive baboon is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
To prevent future risks, establishing understanding and consensus amongst conservationists and farmers may help alleviate wildlife tension and conflict. Presently, education regarding the ecosystem services of baboons and the use of numerous protected areas are being used to work towards this goal.
Legally protected lands and parks are extensive; per the IUCN Red List, the following areas offer refuge to the olive baboon:
Pendjari National Park in Benin; west of the Niger National Park in Burkina Faso; Bénoué, Bouba Ndjida and Waza National Parks, Faro Reserve and Kimbe River and Mbi Crater Game Reserves in Cameroon; Zakouma National Park in Chad; Garamba, Kahuzi-Biega and Virunga National Parks and Tayna Gorilla Reserve in the Democratic Republic of Congo; Awash and Bale Mountains National Parks, Stephanie Wildlife Sanctuary and Menagesha-Suba National Forest in Ethiopia; Bui, Digya and Mole National Parks, Kogyae Strict Nature Reserve, Bomfobiri Wildlife Sanctuary and Willi Falls Reserve in Ghana; Marahoué, Comoé and Mount Peko National Parks in Cote d’Ivoire; Lake Nakuru, Marsabit, Meru, Nairobi and Samburu National Parks and Masai Mara Game Reserve in Kenya; West National Park in Niger; Cross River, Gashaka-Gumti and Kainji Lake National Parks, Ngel Nyaki Forest Reserve, Yankari Game Reserve in Nigeria; Akagera, Nyungwe and Volcanoes National Parks in Rwanda; Dinder National Park in Sudan; Nimule National Park in South Sudan; Arusha, Gombe, Kilimanjaro, Lake Manyara, Serengeti and Tarangire National Parks in Tanzania; Keran and Fazao-Malfacassa National Parks and Koue Reserve in Togo; and Bwindi Impenetrable, Kibale, Murchison Falls and Queen Elizabeth National Parks and Budongo Forest Reserve in Uganda.
- https://primate.wisc.edu/primate-info-net/pin-factsheets/pin-factsheet-olive-baboon/
- https://www.iucnredlist.org/species/40647/17953200#habitat-ecology
- https://www.sciencedirect.com/science/article/pii/S235198942100370X
- https://www.cambridge.org/core/journals/journal-of-tropical-ecology/article/abs/role-of-the-olive-baboon-papio-anubis-cercopithecidae-as-seed-disperser-in-a-savannaforest-mosaic-of-west-africa/ADEE71B1F4C9E812966EC0B202CFC255
- https://web.archive.org/web/20060314104912/http://www.bbc.co.uk/nature/animals/features/300feature1.shtml
- https://animalia.bio/olive-baboon
- https://alltheworldsprimates.org/Members/Home/MasterPrimate.aspx?tid=452
- https://pubmed.ncbi.nlm.nih.gov/20235326/
- https://www.bioexplorer.net/animals/mammals/monkeys/olive-baboon/
- https://www.activewild.com/olive-baboon/
- https://www.theanimalfacts.com/mammals/olive-baboon/?expand_article=1
Written by Dana Esp, February 2024