Chacma Baboon, Papio ursinus
CHACMA BABOON
Papio ursinus
Geographic Distribution and Habitat
The chacma baboon (Papio ursinus), also known as the Cape baboon, dog-faced monkey, or savanna baboon, is an Afro-Eurasian monkey. One of the largest monkey species, it is found in southern Africa, including the Zambezi Valley, southwestern Zambia, Caprivi, and the coasts of southern Angola.
Given the vastness of their territory, chacma baboons can be found in extremely diverse habitats, such as woodland, savanna, steppes, subdeserts, and mountainous regions. Their habitat, however, is limited by water availability. Chacma baboons require daily hydration, preferring water-rich areas over drier localities. Arid areas with scarce or inefficient water supplies are usually avoided. However, a few populations have adapted well to drought-prone areas by supplementing their water intake with regular ingestion of moist plant matter or by relying on artificial water sources—that is, human-made water supplies designed to support agricultural or farming practices.
Three subspecies of chacma baboons are currently recognized: the typical chacma baboon, Papio ursinus ursinus, the grey-footed baboon, Papio ursinus griseipes, and the Namibian chacma baboon, Papio ursinus ruacana.
The first subspecies inhabits the more southern and western regions of the chacma range, including South Africa and some parts of Botswana. The grey-footed baboon can be found in southwestern Zambia, Zimbabwe, Mozambique south of the Zambezi, parts of the Limpopo Province of South Africa, and the Okavango Delta in Botswana. Finally, the Namibian chacma baboon is located in Namibia and southwestern Angola.
Size, Weight, and Lifespan
Chacma baboons are a sexually dimorphic species, meaning there are significant differences between the sexes in terms of size and color patterns.
They are impressively large. Males weigh between 59 and 97 pounds (30–40 kg), measuring up to 30 inches (70 cm), while females are smaller and weigh about half as much. They weigh between 31 and 37 pounds (15–20 kg) and measure around 16 to 24 inches (40–60 cm) in length. Chacma baboons are long-lived animals, with a lifespan ranging from 30 to 45 years.
Appearance
The chacma baboon owes one of its monikers, dog-faced monkey, to its prominent dog-like muzzle and sizable canines. Their fur is almost uniformly brown, with darker fur on their hands, feet, and the back of their necks, and blond undertones over the middle section.
The three subspecies show notable differences in appearance. The grey-footed baboon has a more golden-colored coat and grey hands and feet. Its tail is significantly longer, although it is smaller than the common chacma baboon. The Namibian chacma baboon, while smaller than the common chacma baboon, is significantly darker than the grey-footed baboon.
Infants’ fur changes as they age. When they are born, their fur is black, and the skin on their hands, face, ears, and feet is pink. As they mature, their fur lightens, and their skin darkens. By the age of one, they acquire the traits of adult baboons.
Diet
Chacma baboons have very flexible diets suited to the diverse habitats they inhabit. As an omnivorous species, their diet includes both plants and meat. In addition to leaves, shrubs, and fruit, chacma baboons also feed on certain species of mushrooms, acorns, insects, eggs, roots, and bark. They are resourceful and have an opportunistic appetite, feeding on marine vegetation, soil, and even young antelopes. They are no strangers to scavenging behavior either; they often eat carcasses of already-killed animals, which they are often unwilling to share.
Interestingly, in some regions, around 38% of their vegetarian diet is composed of alien plant species introduced by humans into their habitats. For example, the black wattle, native to Australia, has become an invasive species in several regions of Africa where chacma baboons dominate. This plant has become one of their most coveted foods. They eat the bark, seedlings, and seeds of the plant, spending hours rummaging through the forest floor in search of such delicacies. Unfortunately, this atypical dietary preference has detrimental effects: black wattle contains twice as much potassium and four times as much copper as needed, leading to alarming nutritional imbalances.
Thanks to recent studies, we now know that chacma baboons also feed on antelope excrement. We don’t know exactly why, but it has been suggested that they resort to this unusual behavior due to seasonal food shortages.
Behavior and Lifestyle
Chacma baboons are terrestrial animals, using all four limbs to move across the forest floor, where they spend most of their time feeding. They also socialize there, though the majority of their day is devoted to feeding and traveling. Their daily routine follows seasonal patterns: they spend significantly more time traveling in summer and fall, socialize more in winter, and rest less in the colder months.
Trees play an important role in the lives of these animals. They provide refuge from predators such as leopards, Panthera pardus, lions, Panthera leo, cheetahs, Acinonyx jubatus, and rock pythons, Python sebae. Trees or higher rocky terrains provide safety where they sleep at night. They have fixed sleeping spots and typically don’t travel more than 1.2 miles (about 2 km) from these locations, although they rotate among multiple sleeping spots as needed.
Although chacma baboons are active during the day, they tend to become more active at night as the days grow shorter. This behavior may be linked to disrupted sleep patterns. Both natural light sources, such as the moon, and man-made light sources can influence their nocturnal activities.
Chacma baboons have cheek pouches that they use to store food!
Chacma baboons are a highly social species that live in groups, with numbers ranging from 15 to 200 individuals. Their home range is quite large, extending between 3.5 and 13 miles (5.6–20.9 km). They are a male-dominated species, where high-ranking males rise to power through fighting and aggression.
Chacma baboons are particularly belligerent, characterized by constant power struggles. Juvenile males leave their groups and challenge neighboring groups once they reach maturity. They often usurp older dominant males and gain power within those groups. Once they establish themselves as the alpha male, they kill any infants of the previous dominant male to induce the females to mate with them. Male ranking in this species is particularly unstable, and it is not unusual to witness several changes in dominance over a relatively short period.
On the other hand, females do not migrate; they stay with their birth groups for their entire lives. They form strong hierarchies of their own, which are usually hereditary. We can even speak of nepotism, given how strong such roles are within the group. Their family ties remain strong throughout their lives, but they also befriend unrelated female peers. Such friendships often benefit them, as they ensure support in cases of disputes. Interestingly, females who are mothers form strong bonds with non-dominant males in the group, often with males they have mated with in the past. These males tend to protect their infants from the newly arrived alpha, a protection sorely needed in the usual despotic power succession.
Chacma baboons are a highly expressive species with a rich communication repertoire. Like most primates, chacma baboons spend a lot of time grooming each other, a gesture with both immediate practical use and more abstract communicative value. On one hand, grooming keeps their fur clean; on the other, social grooming strengthens bonds and is used to build alliances, in a “you scratch my back, I’ll scratch yours” manner. Reassuring gestures are often used to soothe group members and lift their spirits after aggression. Swats and bites, which may seem aggressive, are often used to defuse situations and demonstrate that one is unafraid of the other. These actions serve as warning signals.
Visually assertive displays also come into play, as threatening looks can be enough to warn others that serious intentions are at hand. Staring, displaying canines, and raising eyebrows are common visual cues. The receiver might respond aggressively or avert their eyes, clearly understanding the message without the need for further aggression. A “fear grimace,” with teeth exposed and lips pulled back tightly, also signals “peace.”
In chacma baboon society, non-aggressive visual signals hold great significance. One such behavior is “social presenting,” a submissive act where a female or juvenile shows their back to a dominant male. A female might also perform this gesture toward a mother carrying an infant as a mark of respect. This act is often accompanied by “lip-smacking,” a behavior indicating social affiliation within the troop. During this display, the baboon extends its lips and rapidly smacks them together. Dominant males also use this gesture, along with “teeth chattering,” when receiving a presentation from a female or juvenile, reinforcing social bonds within the group.
Their vocal communication is particularly rich. Adult males show dominance within the troop through soft, yet threatening vocalizations known as “grunts,” often referred to as short “uh huh” sounds. These grunts often precede a louder “two-phase bark,” a deep “wa-hoo” call repeated at intervals of 2 to 5 seconds. This call is primarily used in aggressive interactions with other males or when confronting a predator.
Aggressive behavior from a male can prompt a vocal response known as “screeching.” Both male and female baboons of all ages emit a series of high-pitched screams as a defensive tactic. These screeches appear to deter aggressors, potentially reducing the likelihood of escalation.
When fleeing from a threat, subadult and adult baboons emit a distinct, sharp “yakking” sound, while infants and juveniles produce a shorter, chirping “clicking” call. These vocalizations are often paired with the aforementioned “fear grimace.” Distressed infants may also produce an “ick-ooer” cry, characterized by two distinct phases made through pursed lips.
In situations of immediate danger, all troop members—except for adult males—emit a single, sharp “shrill bark” as an alarm call, signaling others to retreat. A higher-pitched variant of this, the “doglike bark,” is used by subadult and adult baboons when individuals become separated from the group.
Not all vocalizations are associated with aggression, fear, or danger. Chacma baboons express friendly intentions through “rhythmic grunts,” soft, low-pitched sounds that serve as greetings when one individual approaches another. Juveniles playing together often produce nasal “chattering”—a sequence of rapid murmurs indicating a peaceful and playful state.
Chacma baboons mate year-round. The alpha male has the right to mate with the females in his troop; nonetheless, given the instability of power within this species, females typically have several mating partners over the course of their lives due to rapid changes in dominance.
Both sexes reach maturity at around five years old. However, males usually start mating only between seven and ten years old, when they are strong enough to challenge other males.
Females carry their babies for six months before giving birth to a single baby, though twins are rare. Babies are completely dependent on their mothers, as in other primate species; occasionally, males will watch over the infants while the mothers forage.
Weaned juvenile chacma baboons are still somewhat dependent on their mothers’ attention. They often show jealousy and increased clinginess when their mothers give birth to another baby, although mothers might still shower their older offspring with attention.
Family ties are very strong in this species. If any baboon with relatives in the group is in trouble, they can rest assured that someone will come to their defense. They are extremely loyal to their kin and form very strong bonds. Fathers often protect their offspring from migrating males who threaten group stability and pose a risk to their children’s lives.
Chacma baboons help aerate the soil by foraging, enriching it, and aiding oxygen flow as they move around searching for food. As a species with a ravenous appetite for fruit, they also disperse seeds, aiding in reforestation. Their scavenging habits contribute to keeping the environment clean by removing decaying animal carcasses. They break down organic matter, which is then more safely recycled into their ecosystem.
The Chacma baboon is classified as Least Concern by the International Union for Conservation of Nature (IUCN, 2018) and appears on the IUCN Red List of Threatened Species. The species is widespread and thriving, with no major threats believed to be impacting its numbers. Unfortunately, due to their opportunistic habits, chacma baboons are often killed by locals who see them as vermin or a nuisance. They are sometimes killed by indiscriminate trapping or poisoning as well.
Chacma baboons tend to steal food from humans and have learned to live near villages and urban areas, where they find safe and consistent food sources. Changes in agricultural practices have fragmented their populations and caused habitat loss, pushing them closer to human settlements. The growing number of human-made structures continues to invade their shrinking environment.
Their meat is sold in markets in South Africa, as it is believed to have medicinal properties. Fortunately, chacma baboons are still abundant and not in danger of extinction. However, humans remain their greatest threat.
Chacma 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 date, it is difficult to calculate the exact number of living chacma baboons. Although their population is stable, conflict with humans is becoming a growing issue. The African Wildlife Foundation (AWF) is one of the organizations overseeing chacma baboon conservation efforts. For example, they use Geographic Information Systems (GIS) to identify threats and devise effective plans.
Various strategies have been implemented to mitigate such conflicts. For instance, electric fences have been installed to deter trespassing baboons and prevent unnecessary killings. Relocating groups or allowing diversified food sources to thrive in human-free zones has been more effective. Unfortunately, these strategies are costly, and due to the baboons’ damaged reputation, farmers might be reluctant to comply.
Education remains the most valuable tool in the fight for these animals’ right to exist. The AWF works with rural communities to build schools and educational centers, providing concrete assistance and resources to inspire future generations to be more mindful of other creatures and foster a stronger sense of duty toward conservation.
- Allan, A., LaBarge, L., Anderson, C., Bailey, A., Jones, B., Mason, Z., Pinfield, T., Schröder, F., Whitaker, A., White, A., Wilkinson, H., and Hill, R., ‘Patterns of Predation and Meat-Eating by Chacma Baboons in an Afromontane Environment’, Folia Primatologica, vol. 94, pp. 1–24, 2022. doi: 10.1163/14219980-bja10004.
- Ayers, A. M., Allan, A. T. L., Howlett, C., Tordiffe, A. S. W., Williams, K. S., Williams, S. T., and Hill, R. A., ‘Illuminating Movement? Nocturnal Activity Patterns in Chacma Baboons’, Journal of Zoology, vol. 310, no. 4, pp. 287–297, 2020. doi: 10.1111/jzo.12747.
- ‘Baboon | African Wildlife Foundation’. Accessed: Oct. 12, 2024. [Online]. Available: https://www.awf.org/wildlife-conservation/baboon.
- ‘Blue Planet Biomes – Chacma Baboon’. Accessed: Sep. 21, 2024. [Online]. Available: https://www.blueplanetbiomes.org/chacma_baboon.php.
- Delaunay, A., ‘Sibling Competition in Two Social Primate Species, Chacma Baboons and Mandrills’, PhD thesis, Université de Montpellier, 2023. Accessed: Oct. 12, 2024. [Online]. Available: https://theses.hal.science/tel-04607841.
- Lewis, M., and O’Riain, J. M., ‘Foraging Profile, Activity Budget and Spatial Ecology of Exclusively Natural-Foraging Chacma Baboons (Papio Ursinus) on the Cape Peninsula, South Africa’, International Journal of Primatology, vol. 38, 2017. doi: 10.1007/s10764-017-9978-5.
- Pebsworth, P., ‘Feeding Ecology of Chacma Baboons (Papio Ursinus) Living in a Human-Modified Environment’, African Journal of Ecology, vol. 58, no. 2, pp. 319–326, 2020. doi: 10.1111/aje.12684.
- Sithaldeen, R., ‘IUCN Red List of Threatened Species: Papio Ursinus’, IUCN Red List of Threatened Species, 2018. doi: 10.2305/IUCN.UK.2018-2.RLTS.T92248020A92248450.en.
- ‘Chacma baboon – SANBI’. Accessed: Oct. 11, 2024. [Online]. Available: https://www.sanbi.org/animal-of-the-week/chacma-baboon/.
- Vea, T., ‘Murder in the Troop ~ Communication Skills | Nature | PBS’. Accessed: Oct. 13, 2024. [Online]. Available: https://www.pbs.org/wnet/nature/communication-skills-introduction/2994/.
- Walton, B. J., Findlay, L. J., and Hill, R. A., ‘On-Primate Cameras Reveal Undocumented Foraging Behaviour and Interspecies Interactions in Chacma Baboons (Papio Ursinus)’, International Journal of Primatology, vol. 45, no. 4, pp. 882–886, 2024. doi: 10.1007/s10764-024-00423-9.
- ‘Wildlife Africa – Chacma Baboon, Behavior, Habits’. Accessed: Oct. 8, 2024. [Online]. Available: https://www.wildlifeafrica.co.za/baboonbehavior.html.
Written by Mirko Cerrone, October 2024