Yellow baboon

TAXONOMY

Suborder: Haplorrhini Infraorder: Simiiformes Superfamily: Cercopithecidae Family: Cercopithecidae Genus: Papio Species: P.cynocephalus Subspecies: P. c. cynocephalus, P.c. ibeanus, P. c. kindae Other names: P. cynocephalus: Papio hamadryas cynocephalus; cynocephalus baboon or savanna baboon; baviaan (Dutch); babouin jaune (French); babbuino (Italian); babian, babuin, or gul babian (Swedish); P. c. ibeanus: Ibean baboon; P. c. kindae: Kinda baboon

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The scientific name for yellow baboons comes from the Greek words kynos and kephalikos, meaning dog and head, respectively. This moniker refers to the quadrupedal stance seen in all baboons as well as the elongated muzzle which makes baboons look like dogs compared to most other monkeys and apes, including humans, which have flat faces (Altmann & Altmann 1970). While Groves (2001) recognizes P. cynocephalus to be a separate species from other baboons, some taxonomists have suggested that all yellow baboons be classified as a subspecies of P. hamadryas (Jolly 1993).

MORPHOLOGY

Yellow baboons are aptly named for the yellow-brown fur which covers their bodies except for their undersides, including the inner surfaces of the limbs, cheeks, and patches of fur on either side of the muzzle, which are white (Rowe 1996; Groves 2001). Adult males and females have longer hair along their flanks compared to the rest of their bodies while males have longer fur at the nape of their necks (Groves 2001). Yellow baboons have a prominent brow ridge covered in yellow-gray fur, but the rest of their face appears black and is only finely covered with fur. Their ischial callosities are also black. They have a protruding muzzle, similar to a dog’s. Yellow baboons walk quadrupedally, with their tails held up slightly and curved away from the body. There is variation between subspecies in the tail position and shape (Groves 2001). All baboons are sexually dimorphic. Wild yellow baboon males have an average height of 1200 mm (3.94 ft) and weigh 25.8 kg (56.9 lb) while females measure 976 mm (3.20 ft) and weigh only 11.0 kg (24.3 lb), on average (Altmann et al. 1993). Variation in length and sharpness of canine teeth is also seen among males and females. Male baboons have long, sharp upper canine teeth compared to females. They use their canines in aggressive interactions with other males and when feeding on large vertebrate prey (Walker 1984; Altmann pers. comm.). Subspecific differences are slight among yellow baboons. Papio cynocephalus cynocephalus infants are born with a black natal coat that changes to the adult coloration as they age, while P. c. kindae infants have red coats at birth and P. c. ibeanus are born white (Groves 2001; Jolly & Phillips-Conroy 2005). Young baboons lose their natal coat starting at six months of age and have adult coloration by the end of month nine (Altmann pers. comm.). Other differences between subspecies include tail shape, body size, and pelage color. “Broken tails” are seen in P. c. cynocephalus; the tail is held almost horizontally away from the body and then falls abruptly, appearing broken. The other species have more gently curved tails. Differences in body size between subspecies can be seen in P. c. kindae , which is much smaller than other subspecies. Papio cynocephalus kindae males are about the same size as females of the other two subspecies and the females are proportionately smaller than the males (Jolly 1993). Finally, unlike the other subspecies, P. c. ibeanus has wavy instead of straight body hair (Groves 2001). Like other cercopithecines, yellow baboons have cheek pouches, sacs in the lower portion of the cheek wall that can be used to store food. Moving between the cheek pouch and the oral cavity through a slit-like opening, food can be stored in the cheek pouch for consumption at a later time (Lambert & Whitham 2001). Longevity in wild female yellow baboons is estimated to be around 14 to 15 years, but females have been recorded living up to 27 years in the wild (Rhine et al. 2000). Because of their social system and patterns of dispersal, it is more difficult to estimate male longevity in the wild (Altmann et al. 1988). The maximum lifespan in captivity is 40 years (Ross 1991).

RANGE

CURRENT RANGE MAPS (IUCN REDLIST): Papio cynocephalus Yellow baboons are found in central Africa from the west to eastern coasts in Angola, Zambia, Malawi, Mozambique, Tanzania, Kenya, and Somalia (Groves 2001). From east of the Luangwa River in Zambia, into Malawi, northern Mozambique, and most of Tanzania, P. c. cynocephalus can be found. Papio cynocephalus ibeanus is found in Kenya and southern Somalia and may range into southeastern Ethiopia while P. c. kindae is found in eastern Angola, southwestern Zambia, and parts of southern Democratic Republic of Congo (Jolly 1993; Groves 2001). There are some areas of overlap in the range of P. cynocephalus and other baboon (Papio) species, but levels of hybridization differ. For example, in Zambia and Angola, P. c. kindae overlaps with P. ursinus subspecies but there is not evidence of interbreeding (Jolly 1993). On the other hand, in Kenya, P. c. ibeanus overlaps with P. anubis and forms a hybrid zone, an area in which individuals show unusual phenotypic diversity resulting from ongoing crossbreeding between species (Samuels & Altmann 1986; Alberts & Altmann 2001). The crossbreeding of P. cynocephalus and P. anubis in this area may have contributed to the formation of the subspecies P. c. ibeanus (Alberts & Altmann 2001). Long-term research on yellow baboons has been conducted since 1971 by Jeanne and Stuart Altmann, Susan Alberts, and their colleagues at Amboseli National Park, in southern Kenya on the border of Tanzania. At Mikumi National Park, Tanzania, Ramon Rhine and others have been studying yellow baboons since 1974. Yellow baboons have also been studied at Ruaha National Park, Tanzania and at the Tana River National Primate Reserve, Kenya. There are virtually no published studies of yellow baboons in Angola, Mozambique, or Malawi, countries that are plagued by civil war and where it is impossible for scientists to study baboon behavior.

HABITAT

Yellow baboons inhabit thorn scrub, savanna, open woodland, and gallery forests throughout their range (Rowe 1996). At Amboseli National Park, yellow baboons are found in semi-arid savannas with stands of acacia trees (Acacia xanthophloea and A. tortilis) breaking up the open grassland (Altmann & Altmann 1970). Because of the small amount of rainfall, they require proximity to water sources and are found in swamps and groundwater forests created from the underground drainage of Mount Kilimanjaro which rises above the park. Annual rainfall averages 335 mm (1.10 ft) and falls in two distinct periods, from November through December and March through May. In this marginal environment, the temperature ranges between 8.89 and 32.2° C (48 and 90° F) (Struhsaker 1967; Bronikowski & Altmann 1996). In the Tana River basin in eastern Kenya where yellow baboons are also found, mean monthly rainfall is much higher than at Amboseli, around 400 mm (1.31 ft) and the climate is slightly more temperate with average temperatures ranging between 22 and 34° C (71.6 and 93.2° F) (Wahungu 1998). The rainy seasons around the Tana River last from April to May and November to December, similar to the seasonal pattern at Amboseli (Wahungu 1998). Yellow baboons that are found in central Tanzania at Mikumi National Park live in the floodplain of the Mkata River (Norton et al. 1987). A mosaic of riverine forests and open grassland, which is seasonally flooded, are found in Mikumi and baboons do not range into the open grassland farther than 2 km (1.24 mi) from stands of trees. The warm, wet season lasts from November through May and the cold, dry season begins in June and continues through October. The average annual rainfall is 842 mm (2.76 ft) and temperatures range from 15 to 35° C (59 to 95° F) (Norton et al. 1987). Water is a limiting factor for baboon groups. The amount of rain determines the amount of standing water and therefore dictates the ranging patterns of baboon groups living in the park (Norton et al. 1987). In addition to being found in undeveloped savannas, yellow baboons are highly adaptable and can take to living alongside humans in rural areas developed for agriculture (Maples et al. 1976; Muoria et al. 2003).

ECOLOGY

Baboons have a diverse diet and are able to exploit a wide variety of foods, a necessity in an environment that is highly seasonal and in which the availability of food varies in abundance throughout the year. Yellow baboons have been called “eclectic omnivores,” because they are extremely selective in their foraging but they have a highly diverse diet (Altmann 1998). For example, in a study done at Mikumi National Park, Tanzania, yellow baboons were recorded eating plant parts from more than 180 species, but of those, only seven species were eaten throughout the year (Norton et al. 1987). Yellow baboons are highly dependent on reliable food sources including two species of acacia — the fever tree (Acacia xanthophloea) and the umbrella tree (A. tortilis) — grasses, and tubers (Altmann & Altmann 1970; Post 1982; Norton et al. 1987). In gallery forests and around permanent water holes, they consume all edible parts of the fever tree including leaves, gum, inner pith, blossoms, seeds, seed pods, and rotten wood. The umbrella tree, which grows in drier parts of their habitat, is utilized in a similar manner (Altmann & Altmann 1970). They also feed on grasses, stripping the seed heads from the blades and consuming the most nutritious part of the grass. During the dry season, they dig around the base of grass blades and consume the corms, which are fleshier and have more water content than the tips of the blades (Altmann & Altmann 1970). Immediately following the rainy season, when grass begins to sprout and is plentiful, they consume the entire blade (Wahungu 1998). Baboons are excellent diggers and utilize tubers, corms, and underground bulbs of plants throughout the year as well (Post 1982; Norton et al. 1987). In addition to grass, tubers, and acacia tree products, yellow baboons also feed on fruits, flowers, orthopterans, termites, beetles, ants, reptiles, birds, bird eggs, small vertebrate prey, and other primates including vervet monkeys (Chlorocebus aethiops) and lesser bush babies (Galago senegalensis). At the Tana River site where baboons are studied, fruit availability peaks after the rainy season and is at its lowest toward the end of the dry season. To cope with these seasonal changes in fruit availability, yellow baboons increase the frequency of consumption of invertebrates as well as eating more roots and tubers (Wahungu 1998). Yellow baboons are reliant on essential localized resources such as water, food, and sleeping sites to determine their ranging patterns, therefore seasonal differences in daily range length and home range size are seen (Altmann 1974). At the Tana River study site, during the months following the end of the rainy season, baboons spend more time foraging and moving in gallery forests areas compared to the dry season, when they move into the open woodland and savanna (Wahungu 1998). The prevalence of fruit in the forest after the rainy season means they do not have to travel as far to obtain nutrient-rich foods and their daily path length is only about 3.4 km (2.11 mi) (Wahungu 2001). In the dry season, when fruits are scarce and foods in the forest are fewer compared to the savanna, yellow baboons expand their daily path movements to exploit as many food resources as are available, moving about 7.2 km (4.47 mi) each day (Wahungu 1998; 2001). While most of the day is spent on the ground, baboons retreat to trees in nearby riverine or gallery forests overnight. Because of its size, the group is spread out over several trees, utilizing a sleeping grove rather than just a single tree (Wahungu 2001). Baboons center their home ranges around the main forested area where sleeping trees are located and return to the grove in the evenings (Wahungu 2001). The group leaves the sleeping grove between 7:00 and 10:00 a.m. each morning. After descending from the trees, the group either remains in the vicinity of the sleeping grove, socializing and grooming or moves into open grassland to forage (Altmann & Altmann 1970). Yellow baboons forage throughout the day, but there are peaks in social activity in the mid-morning, early to mid-afternoon and in the evening after entering the sleeping grove. As they forage, the group moves progressively further from the sleeping grove, but around mid-day, the group turns and begins to forage in the direction of the sleeping grove, working their way back to the forest and entering the sleeping grove between 5:30 and 6:45 p.m. (Altmann & Altmann 1970; Wahungu 2001). One of the reasons baboons seek refuge in sleeping trees is to protect themselves from nocturnal predators. Potential predators include lions, cheetahs, leopards, spotted hyenas, jackals, pythons, chimpanzees (Pan troglodytes), felid-like predators such as servals, caracals, and genets, dogs, and humans (Altmann & Altmann 1970; Wahungu 2001).

SPECIAL NOTES

Baboons appear to be more closely related to humans and are therefore good candidates for animal models in biomedical research (Fridman & Popova 1988a). Yellow baboons, in particular, have been used in research on physiology, blood, the cardiovascular system, neurology, and endocrinology. They have also been used as an animal model to study organ transplantation, alcoholism, epilepsy, and high blood pressure (Fridman & Popova 1988b). About 6% of the biomedical studies involving nonhuman primates include baboon species (Carlsson et al. 2004). Changes in taxonomy and difficulty identifying species have made it impossible to evaluate which baboon species are used most frequently in research (Fridman & Popova 1988a). Content last modified: January 6, 2006 Written by Kristina Cawthon Lang. Reviewed by Jeanne Altmann. Cite this page as: Cawthon Lang KA. 2006 January 6. Primate Factsheets: Yellow baboon (Papio cynocephalus) Taxonomy, Morphology, & Ecology . . Accessed 2020 July 2.

SOCIAL ORGANIZATION AND BEHAVIOR

Like many other cercopithecines, yellow baboons live in multi-male/multi-female groups in which the females remain in their natal groups for their entire lives and males emigrate into a new social group to breed when they reach adult size (Samuels et al. 1987; Bentley-Condit & Smith 1999; Combes & Altmann 2001; Silk et al. 2004). Group size varies from 17 to 77, with the average group size at Amboseli National Park being 39 individuals (Samuels & Altmann 1991). There are slightly more adult females in the group than adult males. At Amboseli, baboon density is about 1.15 individuals per square kilometer (.715 individuals per square mile) (Samuels & Altmann 1991). In areas where food availability, including agricultural foods and human refuse, is high, group size is larger and grows more quickly compared to wild-feeding groups. Group size increases through recruitment and immigration of adult males (Samuels & Altmann 1991). Females remain in their natal groups with their close female relatives. Dominance hierarchies exist among matrilines and young female baboons inherit the rank of their mothers (Bentley-Condit & Smith 1999). Dominant females assert their rank over submissive females by threats, mild aggression, biting, chasing, displacing at feeding sites, and fighting. Submissive animals respond by averting their head and body, avoiding the dominant animal, crouching, and screaming (Bentley-Condit & Smith 1999). Once dominance has been established between animals, though, the dominant individuals do not have to constantly behave aggressively to maintain their status as lower-ranking individuals respect the dominance hierarchy without being threatened (Altmann pers. comm.). When two females are involved in an agonistic dispute, another female will sometimes intervene and lend support to one of the females. These coalitions between female yellow baboons are primarily based on kinship and relative dominance rank (Silk et al. 2004). For example, young females are supported by their mothers and siblings while closely related adult females support one another during agonistic encounters. A female will not lend support to her relative during a dispute when both females involved are higher-ranking (Silk et al. 2004). Higher-ranking females accrue more benefits from maintaining their rank and mediating conflict between lower-ranking females than vice versa. Given priority access to scarce resources and enjoying higher reproductive success, high-ranking females protect their dominance status through the interactions of lower-ranking females (Samuels et al. 1987; Bentley-Condit & Smith 1999). Female rank remains stable for long periods but is very occasionally punctuated by rapid periods of change in which low-ranking females assume high-ranking positions. Some of the conditions under which this may occur includes the death or disappearance of a dominant female who can no longer can support her daughters or sisters in agonistic interactions and therefore the lower-ranking female wins, the increase in size of a subordinate matriline such that the lower-ranking females outnumber the higher-ranking females and can dominate in physical interactions, or when a large number of juvenile females reach adolescence and displace or outcompete older, higher-ranking adult females (Samuels et al. 1987). Males disperse from their natal groups around 8.5 years of age (Alberts & Altmann 1995a). It is at this age that they have reached their full size and fighting ability even though they are capable of reproducing long before this age (Altmann et al. 1988). Male yellow baboons also exhibit a dominance hierarchy in which the largest, most capable fighters, usually the youngest immigrants, are the most dominant. Subordinate males flinch or move out of the way of a dominant male, jump back when approached, grimace, and scream (Noë & Sluijter 1995). Adult and subadult males are dominant over juvenile males and females and adult females, regardless of rank (Hausfater 1975; Bentley-Condit & Smith 1999). One benefit of high rank among males is higher levels of reproductive success, on average, than lower-ranking males (Alberts et al. 2003). Before joining a new group, an emigrating male spends a period of time alone, usually lasting two months (Alberts & Altmann 1995a). This is a dangerous time for a young male because when moving solitarily on the savanna, yellow baboons are subject to higher levels of predation. When a male attempts to enter a new group, he immediately begins challenging other adult males in agonistic encounters in order to obtain reproductive opportunities with adult females (Drews 1996; Alberts & Altmann 2001). These fights can lead to serious injuries in males including cuts, punctures, and scratches from the opponent’s formidable canine teeth as well as broken bones. Indirect injuries include loss of eyesight, bacterial infection, increased vulnerability to parasites, decreased ability to forage, and increased vulnerability to predators (Drews 1996). At one site, it was observed that when males are injured, they drop approximately one step from their previous rank and if the newcomer does not win a fight with an established adult male, he may be evicted from the group (Drews 1996). Like females, yellow baboon males form coalitions and support each other during fights. These coalitions are not based on kinship, however, as males within a group are not likely to be related, but rather are based on fighting ability. Middle-ranked males with average individual fighting abilities form alliances with similarly ranked males in order to dominate in interactions with higher-ranked males (Noë & Sluijter 1995). Once they have achieved top rank within the group, male yellow baboons maintain it for an average of two years before being displaced by a younger male, but tenure can be as short as one month and as long as 11.5 years (Alberts & Altmann 1995a). Males transfer groups throughout their lives and the average residency duration is 2.8 to 4.25 years (Altmann et al. 1988).

REPRODUCTION

Females reach reproductive maturity around 4.5 to five years of age in the wild, and a female first gives birth around six to 6.5 years of age. In captivity, yellow baboons reach adolescence earlier, around three to 3.5 years of age and can give birth within a year after puberty (Altmann et al. 1988; Rhine et al. 2000). The average ovarian cycle lasts about 33 days in yellow baboons and is characterized by anogenital tumescence and menstruation (Hausfater 1975). The peak of swelling is concurrent with ovulation and is a reliable sign to adult males and other females of the reproductive state of the female (Hausfater 1975). One advantage of being a daughter in a high-ranking matriline is that high-ranking daughters reach sexual maturity and reproduce at a younger age, almost an entire year earlier, than low-ranking daughters, increasing their overall potential fitness. Once they reach sexual maturity, female yellow baboons reproduce consistently until old age and associated problems prevent them from reproducing (Rhine et al. 2000). Yellow baboons do not exhibit birth seasonality as females mate and give birth throughout the year. Because of the somewhat marginal habitat in which they live, nutritional stress plays an important part on the regularity of ovarian cycling among females. Female yellow baboons are more likely to cycle during the rainy season, when resources are readily available, compared to the dry season (Altmann et al. 1988). Gestation lasts 180 days and the average interbirth interval is 1.78 years (Altmann 1970; Rhine et al. 2000). Females experience lactational amenorrhea and the ovarian cycle returns as the infant begins to be weaned (Altmann et al. 1988). Physical development in males is slower than in females so that when young yellow baboon females are first conceiving, around age six, their male counterparts are only about half the adult size and are too low-ranking to mate within the group (Altmann et al 1988). When males reach their full size, they usually leave their natal group. Males that do not leave their natal group will stay and reproduce for several years before emigrating, potentially breeding with close relatives. One reason a young male risks inbreeding is the high cost of immigrating into a new group; when males disperse they spend a period of time alone and are subject to predation. Additionally, time spent alone translates into lost mating opportunities (Alberts & Altmann 1995a). Males experience their first sexual consortship around eight years of age (Alberts & Altmann 1995b). Because baboons mate throughout the year, and females are not likely to be fertile at the same time of year, males are able to monopolize mating opportunities with a single female through consortship behavior and mate guarding. High-ranking adult males persistently follow estrous females and repeatedly mate with them during the most fertile phase of their cycle. These consortships often result in the pair lagging behind the rest of the group during traveling and foraging, peripheralization of the couple while the female is most receptive, and intense fights as the dominant male prevents other males from mating with the female (Rasmussen 1986; Alberts et al. 1996). Females exercise mate choice in the formation of these consortships; they can be eager to form a bond with a male, approaching and following him, sexually presenting, and allowing copulations or they can avoid an approaching male by walking away, rarely presenting, and not tolerating copulations (Altmann et al. 1988). When two yellow baboons form a consortship, it may last a morning, an afternoon, or an entire day, and females can have multiple mates during the estrus period (Hausfater 1975). Females do not always choose males based on rank but on mutual cooperation or “friendship” formed by grooming, maintaining close proximity, and infant handling (Rasmussen 1986; Altmann et al. 1988). Because the highest-ranking males in a group are likely to be new immigrants, females that have not established relationships with new males avoid them, especially if they have young offspring. Lower-ranking males form alliances and can harass newly immigrated but dominant males and protect adult females with which they have bonds. Overall, though, dominance rank of a male indicates reproductive success so that high-ranking males have more mating opportunities, more offspring, and increased fitness compared to lower-ranking males (Alberts et al. 2003).

PARENTAL CARE

Females are the primary caregivers to their dependent offspring, but males contribute to the survival of infants in direct and indirect manners (Altmann 1980; Altmann et al. 1988; Stein 1984). At Amboseli National Park, survival rates of the first year are around 79%, and maternal effects such as rank influence the survival of individual infants (Altmann & Alberts 2005). Shortly after birth, baboon infants cling to their mothers largely unaided and begin to nurse. For about the first week of life, the mother offers a supportive embrace to the infant to ensure that it does not lose its grip when she is moving (Altmann 1980). For the first two weeks of life, the infant will not move from the mother, but will increasingly begin to move around on her ventrum. They have poor motor control in the early weeks of life, and any locomotory attempts usually end with the infant falling over after the first few steps. By the end of the second week, the infant attempts to break contact with its mother, but the mother is extremely attentive and at any sign of distress or any change in the surroundings, including approaching group members, the mother immediately retrieves her offspring (Altmann 1980). Generally speaking, higher-ranking mothers are more permissive with their infants than lower-ranking females. High-ranking females allow their infants to be handled by other group members and groomed by others more frequently compared to low-ranking ones (Altmann 1980). A new infant attracts the attention of all group members, regardless of the mother’s rank, and this is one reason that permissiveness and protectiveness are correlated with rank. Yellow baboon infants of low-ranking mothers are occasionally stolen or kidnapped by higher-ranking females. The mother is helpless to retrieve her infant because she is comparatively lower in the dominance hierarchy and is not likely to have female support to fight with higher-ranking females (Altmann 1980). The infant rides ventrally for two to three months but then begins to move around to ride on the mother’s dorsal side. At around two months of age, the mother begins to initiate breaks in contact with her infant, and by three or four months of age, infants spend increasing amounts of time in peer interactions, including play. Their locomotor skills have increased greatly by this point and they are able to climb some trees. They are still highly dependent on their mothers for food and transportation, especially if the group is traveling quickly, but they become increasingly independent as they age (Altmann 1980). They increase the amount of solid food consumed around four months of age, and within one year most yellow baboon infants can survive without their mother, though they continue to nurse occasionally and sleep in the mother’s sleeping tree until a younger sibling is born (Altmann 1980; Rhine et al. 1985). The amount of time in contact with the mother begins at 100% in the first week of life and decreases by eight or nine percent each consecutive month of life. The mother increasingly resists an infant’s attempts to be carried and nurse as the infant ages such that by six to eight months of age, she often dislodges the infant while walking and ignores the infant when it attempts to make contact (Altmann 1980). Weaning is almost completed by the end of the first year, but until another sibling is born, a young yellow baboon will nurse during times of extreme stress or alarm, as a form of comfort (Altmann 1980; Rhine et al. 1985).

COMMUNICATION

Visual communication among yellow baboons is important as a measure to deter agonistic interactions involving physical fighting, especially among males. Fighting is often very costly in terms of injuries that can lead to a host of other secondary problems such as infections, permanent injury, inability to forage, and inability to travel with the group, leading to higher likelihood of predation. Baboons therefore have highly ritualized signals which communicate threat without escalating to physical fighting (Drews 1996). These include intense staring, eyelid displays where one male blinks slowly, exposing his whitish eyelids to his potential competitor, ground slapping, audible chewing or teeth grinding, yawning (which displays the formidable canine teeth), eyebrow-raising, ear flattening, jerking of the head down and forward, piloerection, rearing onto the hind legs, and shaking of rocks and branches (Hall & DeVore 1965; Altmann 1967; Drews 1996). Females also use the yawn display during times of social tension (Hall & DeVore 1965). Some friendly signals seen in baboons include lipsmacking, grinning, looking over one shoulder, presenting any body part for grooming, and ear-flattening (Hall & DeVore 1965). Vocalizations among yellow baboons include those given only by adult males, those heard from any adult baboon, and juvenile calls. Some calls given only by adult males include “barks,” loud calls that can be heard for distances over.8 km (.5 mi) and which are given as a reaction to dangerous situations such as the presence of predators, “grunts,” heard as males begins to threat display, “roars,” loud vocalizations that are heard during physical confrontations, and “grating roars,” resonant vocalizations with low intensity given by dominant adult males (Hall & DeVore 1965). Calls that can be given by any adult yellow baboon include “screeching,” heard as a submissive animal retreats from a more dominant group member; “shrill barks,” given in response to the sudden appearance of animals of different species, including predators; “dog barks,” heard when one animal is separated from the rest of the group, and “grunts,” heard when the group feeds together and as they gather in the sleeping grove at night (Hall & DeVore 1965). One vocalization given only by adult females in estrus is the “muffled growl,” a sound made as the female inhales and exhales with her mouth almost closed and puffing out her cheeks. This is also called a “copulation call” as it is heard during and after copulation (Hall & DeVore 1965; Semple et al. 2002). Juveniles, including infants, also make vocalizations unique to their age-class, including “chirplike clicking,” heard when the young baboon is separated from its mother or when it is frustrated and “ick-ooers,” heard in similar situations (Hall & DeVore 1965). Content last modified: January 6, 2006 Written by Kristina Cawthon Lang. Reviewed by Jeanne Altmann. Cite this page as: Cawthon Lang KA. 2006 January 6. Primate Factsheets: Yellow baboon ( Papio cynocephalus ) Behavior . . Accessed 2020 July 2.

INTERNATIONAL STATUS

For individual primate species conservation status, please search the IUCN Red List. Also search the current scientific literature for primate conservation status (overall as well as for individual species), and visit CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora).

Conservation information last updated in 2006 follows, for comparison:

CONSERVATION THREATS & POTENTIAL SOLUTIONS

Threat: Harvesting (hunting/gathering) Hunting pressure on yellow baboons is increasing in some parts of their range and could reach unsustainable levels if it is not curtailed. Wildlife is the main source of protein for some people living in rural areas near forests, and when animals such as baboons, which are skilled crop-raiders, become nuisances, the harvesting increases to curb the population (FitzGibbon et al. 2000). The hunting pressure also increases as human population density increases. Eventually, hunting will extirpate those species that cannot reproduce quickly enough to replace members of the population lost to hunting (FitzGibbon et al. 2000). Yellow baboons, like other primates that have relatively slow reproductive rates, are likely to experience this population reduction as they cannot reproduce fast enough to compensate for the hunting in some areas. Though they are not threatened currently, decreasing local populations in and around forests decreases the overall conservation value of the forests and limits other activities such as ecotourism (FitzGibbon et al. 2000).

Threat: Accidental Mortality While the yellow baboons are not threatened with extinction and are currently of little conservation concern, a pattern of accidental mortality has emerged among a group of baboons in Mikumi National Park, Tanzania. A highway connecting Tanzania and Zambia cuts through Mikumi, and baboons and other wildlife are increasingly threatened by fast-moving vehicles on this stretch of road. Constant improvements to road conditions allow drivers to increase their speed and subsequently more animal deaths have been reported (Drews 1995). About 18 yellow baboons are killed each year as a result of public traffic on the highway, and this cause of death can contribute up to 10% of the total yearly losses in each group. As roads are built and paved through remaining rural areas throughout the range of the yellow baboon, it is possible that collisions with vehicles can significantly decrease population growth in some areas (Drews 1995).

Threat: Changes in Native Species Dynamics Natural changes in the ecosystem of Amboseli National Park resulted in high mortality among yellow baboons during the late 1960s. During this time, significant changes to the habitat occurred, though it is unclear if these changes directly affected the baboons or if they were indirectly responsible for the decrease in population size and density (Altmann 1998). The landscape at Amboseli was indirectly affected by human population growth in the areas surround the park. As the human population in surrounding areas grew, an attempt to separate the park from human areas through fencing caused the elephant population within the park to be confined. Some 700 elephants became restricted to the boundaries of the park and rather than moving over huge distances, foraging as they moved, the elephants remained inside the park, destroying fever trees ( Acacia xanthophloea ) and eliminating food sources and shelter for many mammals, including baboons (Cheney & Seyfarth 1990). Another source of mortality for the fever trees was the rising water table caused by runoff from Mount Kilimanjaro, which rises above Amboseli. These two factors played some role in the annual die-off of 46% of the population of yellow baboons in the park during the years from 1964-1969 (Altmann 1998).

LINKS TO MORE ABOUT CONSERVATION ORGANIZATIONS INVOLVED IN Papio cynocephalus CONSERVATION Chimfunshi Wildlife Orphanage Gombe Stream Research Centre Israeli Primate Sanctuary Colobus Conservation Content last modified: January 6, 2006 Written by Kristina Cawthon Lang. Reviewed by Jeanne Altmann. Cite this page as: Cawthon Lang KA. 2006 January 6. Primate Factsheets: Yellow baboon (Papio cynocephalus ) Conservation . . Accessed 2020 July 2.

REFERENCES

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Content last modified: January 6, 2006

IMAGES

	Papio cynocephalus Photo: Dennis Rasmussen
	Papio cynocephalus Photo: Dennis Rasmussen
	Papio cynocephalus Photo: Irwin S. Bernstein
	Papio cynocephalus Photo: J. Stephen Gartlan
	Papio cynocephalus Photo: Kathryn L. Rasmussen
	Papio cynocephalus Photo: Kathryn L. Rasmussen
	Papio cynocephalus Photo: Kathryn L. Rasmussen
	Papio cynocephalus Photo: Kathryn L. Rasmussen
	Papio cynocephalus Photo: Kathryn L. Rasmussen
	Papio cynocephalus Photo: Kathryn L. Rasmussen
	Papio cynocephalus Photo: Kathryn L. Rasmussen
	Papio cynocephalus Photo: Kathryn L. Rasmussen
	Papio cynocephalus Photo: Kathryn L. Rasmussen
	Papio cynocephalus Photo: Mark Murchison
	Papio cynocephalus Photo: Mark Murchison
	Papio cynocephalus Photo: S. J. Bleiwess