As in all highly social species, communication is varied and complex. Chacma baboons utilize visual signals and gestures, vocalizations, and tactile communication.
Visual signals include social presenting, in which a female or juvenile displays its hind quarters to a male. It can also be done by a female who has approached another female with her black infant. This submissive signal differs from sexual presenting (which females do to elicit copulation), and is often accompanied by lip smacking. Staring is a threat behavior, the effect of which is enhanced by the differently colored fur in the region of the eye which is revealed when the baboon stares. Eyebrow raising is a similar aggressive gesture. Canine tooth display through a tension yawn is another threatening gesture. It is performed by lower-raking males toward higher-ranking males who are consorting with estrus females or who possess meat. Male baboons who are close to one another can use tooth grinding to threaten one another. Baboons who are being threatened use rapid glances in the opposite direction to break tension. Adult males who are guarding mates sometimes sit with their erect penis is plain view. This penile display communicates the male’s presence to other males.
Teeth chattering and lipsmacking, although not technically vocalizations, are auditory cues of reassurance, often performed by a dominant animal when another is presenting to him. A female may also lipsmack when approaching a mother and her black infant.
Vocalizations made by chacma baboons include a two-phase bark, or "wahoo" call, which adult males direct toward feline predators or toward other males. It is thought to communicate the presence of the male and his arousal. This call may be preceded by grunting, a soft threat call. Screeching is common during aggressive encounters, and can be made by any age or sex class. It appears to inhibit aggression. Subadult and adult baboons produce a yakking call when retreating from a threatening animal. This call is often accompanied by a grimace of fear. A shrill bark is produced by all except adult males to indicate alarm, especially due to sudden disturbances. Finally, rhythmic grunting may be produced by all chacma baboons except infants when they wish to signal reassurance to another animal.
Juveniles and infants produce some vocalizations unique to their age class. These include chattering, which is a nasal, grunt-like call emited during play. They also produce an ick-ooer sound which communicates a low level of distress.
Adult females of this species produce a vocalization during copulation called a muffled growl. The mouth is closed, and the cheeks expand and contract during this call.
Tactile communication is common in cercopithecines. Social grooming is used to reinforce social bonds, as well as to remove parasites and debris from the fur. Social mounting is a reassurance behavior. Anubis baboons also perform a friendly nose-to-nose greeting.
Chemical communication has not been reported for this species. However, female anubis baboons are known to produce aliphatic acids when they are sexually receptive. These acids are thought to enhance a female’s sexual attractiveness. It is possible that female chacma baboons also produce these acids.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Chacma baboons are not listed as threatened or endangered.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
All baboons can be terrible crop pests, as they are not particularly shy of humans. They are large animals which can be aggressive when confronted.
Negative Impacts: injures humans (bites or stings); crop pest
Chacma baboons are very interersting animals, and provide a great deal of entertainment to people who visit them in zoos. Some of these animals have been used in medical research.
Positive Impacts: research and education
Because chacma baboons are prey items, they form an important link in local food webs, making nutrients they obtain from plants and small animals available to larger animals. They dig for tubers, roots, rhizomes and corms, so it is likely that these animals help to aerate the soil where they forage. Also, it is likely that they play some role in dispersing seeds they eat.
Ecosystem Impact: disperses seeds; soil aeration
Chacma baboons are known to eat fruits, including Kigelia pinnata fruit and figs from both Ficus sycomorus and Ficus burki. They also eat leaves, including the crowns of Cypress trees, tree gums, insects, eggs, seeds, including the green seeds of Acacia nigrens, flowers, water lilies (Nymphaea caerulea), grass, rhizomes, corms, roots, tubers, and small vertebrates.
One feeding adaptation thought to be shared by all baboons is the ability to subsist on a relatively low quality diet. Baboons can subsist on grasses for extended periods of time. This allows them to exploit dry terrestrial habitats, like deserts, semideserts, steppes, and grasslands.
Animal Foods: birds; mammals; reptiles; eggs; carrion ; insects; terrestrial non-insect arthropods
Plant Foods: leaves; roots and tubers; wood, bark, or stems; seeds, grains, and nuts; fruit
Primary Diet: omnivore
The distribution of chacma baboons is primarily water limited. They are found throughout much of southern Africa. These baboons are found in the countries of Angola, Botswana, Mozambique, Namibia, South Africa, and Zambia.
This species is part of a complex of closely related African baboon species. We have an account of the whole genus under Papio.
Biogeographic Regions: ethiopian (Native )
Chacma baboons are found in wooded highlands, grassland steppe, and savanna habitats.
Habitat Regions: temperate ; tropical
Terrestrial Biomes: savanna or grassland ; chaparral ; scrub forest
A chacma baboon (P. ursinus) is reported to have lived 45 years in captivity. It is unlikely that many individuals live this long in the wild.
Range lifespan
Status: captivity: 45 (high) years.
Average lifespan
Status: captivity: 27.6 years.
Average lifespan
Sex: female
Status: captivity: 31.2 years.
Average lifespan
Status: captivity: 45.0 years.
These monkeys are sexually dimorphic in size and pelage characters. Head and body length is reportedly between 508 and 1.143 mm, with the tail adding an additional 456 to 711 mm to the total length. Males weigh from 26 to 31 kg and females around 15 kg. Animals found in the Kalahari desert are reported to be somewhat smaller than average. The average brain weight in adults of this species is 214.4 g.
Males have large canine teeth, whereas the teeth of the females are much smaller. These animals have 32 teeth. The first lower premolar is modified and serves as a hone for the upper canine tooth. The skull of these baboons is large, and the face has a characteristic downward flex. The upper face is narrow and deeply constricted. The skin of the face is a dark, purple-black. The tail is bent.
Pelage of typical chacma baboons is dark brown to black dorsally, with the underparts and sides of the muzzle lighter. The fur on the hands and feet is black. The overall hair color is produced by individual hairs which are black with a single yellow-brown band. Light hairs typically have a black tip. Although males are not maned, as they are in anubis , hamadryas, and guinea baboons, they do have longish tufts of hair at the nape. The facial skin and the skin surrounding the ischial callosities is purplish-black. The natal pelage is black, and is replaced by adult-like fur around 6 months of age.
It should be noted that there is geographic variation in pelage coloration. Gray-footed baboons, an identifiable subgroup within the species, are found in the northeastern part of the species range. These baboons are slightly smaller than typical chacmas. They are distinguished from typical chacmas by the coloration of the fur, which is gray-buff. The fur on their hands and feet is the same grayish color as their arms, rather than the black seen in typical chacmas. Hairs show a different banding pattern than typical chacma baboons, with black tips and black rings. The post-orbital constriction is reduced in this variety of baboon. As in typical chacma baboons, the natal pelage is black, and this fur is replaced by the adult color around 6 months of age.
Transvaal baboons, another subgroup within P. ursinus, are known from a limited number of specimens collected near the region where gray-footed and typical chacma baboon ranges meet. It is not known whether this variety represents a stable baboon phenotype (and therefore a distinct population), or simply a few animals produced from hybridization of typical-chacma and gray-footed chacma baboons. Transvaal baboons are somewhat intermediate between the typical chacma and the gray-footed variety, supporting the hypothesis that they may represent hybrids of the other forms of chacma baboons. In fur color and hair-banding pattern they resemble gray-footed baboons. However, they possess black feet, like typical chacmas. In size and cranial shape, these baboons resemble typical chacmas. Nothing is known about the natal pelage of these baboons.
Range mass: 15 to 31 kg.
Range length: 508 to 1,143 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger; ornamentation
Two predator species are known for chacma baboons in Botswana: leopards, and lions. Predation rate has been estimated at 9 percent of the population per year. Of these animals, 18 percent are thought to be infants, 18 percent juveniles, and 13 percent adult males. A full 50 percent of predation deaths are of adult females.
Risk of predation may have an influence on how animals organize themselves within a moving group of chacma baboons. Animals who are less able to defend themselves from predators, or who have greater fear of predators, may locate themselves toward the rear of a groups approaching potentially dangerous areas, such as water holes. Also, these vulnerable individuals may by virtue of greater fear, may end up at the front of the group as it retreats from a predator.
Baboons have been known to attack leopards. Males, with their elongated canines, can inflict great damage on potential predators. It may be that the high percentage of females, infants, and juveniles taken by predators is related to a preference by predators for these less dangerous prey items.
Known Predators:
Reproductive behavior in P. ursinus is closely tied to social organization. When these animals live in multi-male, multi-female troops, there is the potential for any male to mate with any female. Because of this, males in multi-male troops compete fiercely for access to sexually receptive females. In general, a male’s ability to consort with a female and exclude other males from access to her is related to the male’s ability to compete with other males. There is therefore a correlation between male dominance rank within the troop and mating success. Larger, younger, and stronger males have a distinct advantage in this type of competition.
However, as in many social animals, there are other factors which affect a male’s mating success. For example, in P. anubis males may form alliances with other males, which can subvert the normal dominance hierarchy. Two males, neither of whom can dominate a third male alone, may join forces and together, as a coalition, these males may succeed in securing access to a sexually receptive female. Such coalitions may occur in chacma baboons, although research has yet to address this behavior in P. ursinus.
In anubis baboons, males also follow a strategy of developing "friendships" with females, which enhances their opportunities to mate. In these friendships, males groom, share food, and have strong affiliative ties with particular females and their offspring. It is common for males to defend their female friends during agonistic encounters with other females, and with other males. These associations are not confined to the period during which females are sexually receptive, but span the entire gamut of the female’s reproductive life—including pregnancy, lactation, and time spent cycling. Females tend to exhibit a preference for mating with their male friends, and therefore make consortships with their male friends more likely. In addition, because females prefer their friends as mates, they are more likely to cooperate with them in the maintenance of a consortship than they are to cooperate with other, less favored, males. These types of long-term friendships may also exist in chacma baboons, although further research is needed to clarify this point.
Females clearly exert some mate choice. In addition to having sexually proceptive behavior, in which the female makes some decision about which males she will mate with by presenting her hindquarters to those males, they may refuse to mate with some males. When new males immigrate into a troop, females may help or hinder their chances of success by developing affiliative relationships with the immigrating males. In this way, females may choose which males will be in their potential mating pool.
Mating System: polygynous ; polygynandrous (promiscuous)
Reproduction in P. ursinus is related to the social structure of this species. The social structure is somewhat variable, with the majority of animals living in multi-male, multi-female troops reminiscent of anubis baboons. In some cases, however, the social structure resembles that of hamadryas baboons, with single males controlling a group of females. Mating in multi-male, multi-female troops is polygynandrous, with both males and females mating with multiple partners. Mating in One Male Units (OMUs) is necessarily polygynous.
Most matings in multi-male, multi-female troops occur during consortships. Consortships arise when a male, through aggression toward potential rivals, is able to maintain exclusive sexual access to a female. Females may consort with multiple males during the periovulatory period, although they consort with only one male at a time. Because it is apparently easier for a male to maintain exclusive access to a female if the female is cooperative, there is a significant amount of female mate choice, with females preferring some partners over others.
In OMUs, males do not alter their general behavior toward females, with the exception of mating with them mostly when the females are close to ovulation. Males in OMUs do not consort with females. If another adult male enters the group, however, this behavior changes drastically, with typical competition between males and consortships developing.
Females characteristically have an estrous cycle of 31 to 35 days in length. There is a noticeable menstrual flow for approximately three days per cycle if the female does not conceive. During the period around ovulation, the perineal skin of the female swells, alerting the males to her potentially fertile condition, and enhancing her attractiveness to them. Females are sexually receptive and mate throughout their cycle, but copulations peak at midcycle when the female is likely to ovulate. Mating is initiated by the female, who presents her hindquarters to the male. Like hamadryas baboons, chacma males are serial mounters. A male will mount a female several times, with 1 to 20 thrusts per mount, before ejaculating. When the female is cycling, mating frequency can be as high as 7 to 12.2 copulations per hour. Mating does not occur during pregnancy.
Gestation is probably similar to that of other Papio species, which ranges from 175 to 180 days. Females give birth to a single offspring. The newborn of P. anubis weighs 1068 g on average, and the young of chacma baboons are probably similar in size. The neonate has a black coat, making it easy to distinguish from older infants. An infant is completely dependent upon its mother for the first few months, until it begins to eat solid food and is able to walk on its own. Females have an interbirth interval ranging from 18 to 24 months. As in other baboons, it is likely that this interval varies according to a number of factors. In anubis baboons, females who are older or have a higher rank tend to have shorter interbirth intervals. Interbirth interval is also shorter if an infant dies before weaning.
Data on the nursing period in this species are scanty. However, it is likely that timing and patterns resemble other members of the genus. Weaning typically occurs in P. anubis around 420 days of age. Lactation is a huge cost for adult females, and has been implicated in dramatic weight reductions in anubis females. Lower ranking and younger females probably take longer to recover adequate body weight to reproduce than do older, dominant females, due to their reduced access to prime feeding sites. This would explain their longer interbirth intervals.
The onset of puberty and attainment of adult size are variable and are associated with nutrition levels. For example, in P. anubis populations where baboons are known to raid human crops, and to thereby secure greater access to nutrients than naturally foraging animals, puberty can occur much earlier. The effect of nutrition on growth in P. anubis is so strong that as little as 15 to 16 weeks of dietary variation in newborns can have lasting effects on overall rates of female growth, absolute adult weight, and age at menarche. It is reasonable to assume that chacma baboons are similarly affected.
In P. ursinus females reach sexual maturity at approximately 3 years of age. Male sexual maturity occurs around 5 years of age. Within about a year, these animals will reach full size, or experience their first birth. There are no data available regarding the maturation of testicles or sperm production in this species. However, because chacma baboons have a variable mating system, and mating system differences have been implicated as the evolutionary cause of differences in the schedule of sexual maturation between anubis and hamadryas baboons, such data would be very interesting.
Breeding interval: These animals can breed every 1.5 to 2 years.
Breeding season: Mating can occur throughout the year.
Range number of offspring: 1 (low) .
Average number of offspring: 1.
Average time to independence: 12 months.
Average age at sexual or reproductive maturity (female): 3 years.
Average age at sexual or reproductive maturity (male): 5 years.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Most parental care is performed by the female. Females nurse, groom, and play with their offspring. Females express different patterns of infant care, often associated with rank and age. In yellow baboons, higher-ranking females tend to be more "permissive" in their parenting than lower ranking females, who tend to me more nervous and "restrictive," preventing their offspring from moving away from them.
There does not seem to be cooperative care of offspring among females in P. ursinus, but it is not uncommon for females other than the mother to groom an infant, sometimes providing allomaternal care to the infant. As in other baboons, subadult and juvenile females who have not yet reproduced themselves are most likely to exhibit allomaternal behavior. As is the case for all baboons, infants are very attractive to other members of the social group, and are the focus of a great deal of investigation and attention, especially while they are still displaying their black natal coat. In extreme cases, female anubis baboons may kidnap the offspring of other females. Lower-ranking females are more often subject to this extreme form of harassment than are higher-ranking females. Other factors known to affect the incidence of allomaternal behavior in other species include the infant’s age, and relatedness of the allomother to the mother and infant.
Males have complex relationships with infants and juveniles, which in some cases may be a form of parental care. In other savanna baboon species, males are known to carry, protect, share food (especially meat), groom, and play with, the offspring of their female friends. Because they are more likely to mate with their female friends than they are with other females, these infants and juveniles are more likely to be their own offspring than are other immature animals within the troop. This behavior, therefore, can be interpreted as paternal. Although not specifically reported for chacma baboons, it is likely that this behavior does occur in this species.
However, it should be noted that the relationship between adult males baboons and immature animals may be more complex than this. There may be some form of reciprocity involved. Adult males will often carry infants during tense interactions with other adult males. This carrying can be initiated either by the adult male or by the infant. Such contact with an infant during agonistic encounters may have the effect of inhibiting aggression by other males. The favors bestowed upon an infant used as a buffer may therefore be a form a "payback" from the adult male. However, since the tendency to use an infant as an agonistic buffer is related to familiarity with the infant, and in baboons and macaques familiarity with an infant is associated with the probability of paternity, it is impossible to separate the nepotism from the reciprocity of such interactions.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning; inherits maternal/paternal territory; maternal position in the dominance hierarchy affects status of young
Chacma Baboons (Papio Ursinus) are often regarded as pests, especially in the Cape region, but these crazy creatures are actually very intelligent and share a lot of behavioural traits with us humans, which is maybe why people find them so pesky.
The Chacma Baboon, like all other baboons, is from the Old World monkey family, and also one of the largest baboon species, with a body length of up to 115 cm, and weighing from 15 to 35 kg. But unlike their brothers from up north, male Chacmas don’t have manes. Chacmas do however have a shaggy patch of hair on the nape of their necks. Chacmas are gray to dark brown, with darker extremities and tail, and running speeds of up to 45kph can be achieved. Imagine that!!
Baboons are sexually dimorphic, males being significantly larger than females (reaching sexual maturity at around six or seven years of age), and males develop canine teeth as long as 5 cm, larger than those of lions.
Chacmas can be found in most of southern Africa, from South Africa north to Angola, Zambia and Mozambique, and are divided into three subspecies within that range (the Cape Chacma, the Gray-footed Chacma in northern S.A. and Zambia, and the Ruacana Chacma in Namibia and southern Angola), with colour and size variations in the different areas.
Although they spend most of their time on the ground searching and foraging for food, these silly baboons spend their evenings in high trees (sometimes sleeping on very narrow branches!) or rocky outcrops, escaping the possible dangers of leopards and other predators.
Chacma Baboons mainly prefer nice fresh fruits, nuts, tubers and invertebrates, but they are omnivorous, which means that they eat anything and everything, even human-derived food! That is why it is super important NOT to feed these gentle beings and NOT to have any food around them, otherwise they might not be viewed as gentle any more.Many people claim to have been ‘attacked’ by baboons before, but these misunderstood animals were probably just trying to retrieve the most important thing they see in front of them, food!
Baboons are very social animals and communicate through various means, including body attitude, facial expressions, touch and sounds like lip-smacking, grunting, kecking and wahooing. Troops are characterised by a dominance hierarchy, females inheriting it from their mothers, while male ranking is tenuous and have to be fought for. Females thus form the core of the troop as males move between troops in their quest for the position as alpha male.
Females give birth to one infant after a gestation period of six months, generally reproducing once every two years, and couples often stay together to raise the young. Males as well as other females from the troop have even been witnessed to foster infants if the mother was killed.
Even though Chacmas are not considered as threatened, there is an on-going war between humans and the wildlife, as human expansion increases and foraging grounds and the natural environment of baboons decreases. Because they live near human habitats, baboons are shot, electrocuted, poisoned, run over and captured for the pet industry or lab research. Human intervention has thus been found to influence troop structures, and there has been a considerable loss in numbers in certain areas.
According to Tenikwa Wildlife RehabilitationCentre, Chacma baboons have been on the Cape Peninsula for over 1 million years. However, unless trends change, the remaining 250 Chacma baboons of the Cape South Peninsula face extinction within 10 years.
They go on to say that in 2005, 50% of baboon deaths were caused by humans and by 2008, this had increased to 70%. Most of these deaths were from vehicles or guns.
For more fantastic info and common misconceptions about these whimsical baboons, visit this very rad informativesiteput together by Larissa Swedell and Julian Saunders.
For more information on MammalMAP, visit the MammalMAPvirtual museumorblog.
The chacma baboon (Papio ursinus), also known as the Cape baboon, is, like all other baboons, from the Old World monkey family. It is one of the largest of all monkeys. Located primarily in southern Africa, the chacma baboon has a wide variety of social behaviours, including a dominance hierarchy, collective foraging, adoption of young by females, and friendship pairings. These behaviors form parts of a complex evolutionary ecology. In general, the species is not threatened, but human population pressure has increased contact between humans and baboons. Hunting, trapping, and accidents kill or remove many baboons from the wild, thereby reducing baboon numbers and disrupting their social structure.
Due to hybridization between different baboon (Papio) populations across Africa, authors have occasionally grouped the entire radiation as a single species, the hamadryas baboon, Papio hamadryas. Arbitrary boundaries were then used to separate the populations into subspecies.[3] Other authors once considered the chacma baboon a subspecies of the yellow baboon, Papio cynocephalus, although it is now recognised as a separate species, Papio ursinus. The chacma baboon has two or three subspecies, depending on which classification is followed. Grubb et al. (2003) lists two subspecies,[4] while Groves (2005) in Mammal Species of the World listed three.[1] This article follows Groves (2005) and describes three distinct subspecies. In the Grubb et al. (2003) paper, P. u. raucana was believed to be synonymous with P. u. ursinus.[4]
P. u. ursinus
Cape of Good Hope, South Africa
_male.jpg)
Male P. u. griseipes
Chobe National Park, Botswana
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Male P. u. griseipes
Chobe National Park
_female_head.jpg)
Female P. u. griseipes
Chobe
_juvenile.jpg)
Juvenile P. u. griseipes
Chobe
The chacma baboon is perhaps the longest species of monkey, with an adult body length of 50 to 115 cm (20 to 45 in) and tail length of 45 to 84 cm (18 to 33 in).[5][6] It is also one of the heaviest; the male weighs from 21 to 45 kg (46 to 99 lb) with an average of 31.8 kg (70 lb). Baboons are sexually dimorphic, and females are considerably smaller than males. The adult female chacma weighs from 12 to 25 kg (26 to 55 lb), with an average of 15.4 kg (34 lb). Adult males can in some instances be about twice as long and three times as heavy as adult females.[7][8][9][10] It is similar in size to the olive baboon, averaging slightly higher in mean body mass, and of similar weight to the more compact mandrill, the males of which weigh on average about 1 kg (2.2 lb) more than a chacma baboon, the females weigh 3 kg (6.6 lb) less than the female chacma. While the mandrill is usually crowned the largest of all modern monkeys, going on total length and average (but not maximum) body weight between the sexes, the chacma baboon appears to be the largest extant monkey.[9][11] The chacma baboon is generally dark brown to gray in color, with a patch of rough hair on the nape of its neck. Unlike the males of northern baboon species (the Guinea, hamadryas, and olive baboons), chacma males do not have a mane. Perhaps the most distinctive feature of this baboon is its long, downward-sloping face.[12][13] The canine teeth of male chacma baboons have a mean length of 3.86 ± 0.30 cm (1.52 ± 0.12 in) at the time they emigrate from their natal troop. This is the time of greatest tooth length as the teeth tend to wear or be broken thereafter.[14]
The three subspecies are differentiated by size and color. The Cape chacma is a large, heavy, dark-brown, and has black feet. The gray-footed chacma is slightly smaller than the Cape chacma, lighter in color and build, and has gray feet. The Ruacana chacma generally appears to be a smaller, less darkly colored version of the Cape chacma.
The chacma baboon inhabits a wide array of habitats including woodland, savanna, steppes, and sub desert, from the grassy alpine slopes of the Drakensberg to the Kalahari desert.[2] During the night, the chacma baboon sleeps atop steep hills, high cliffs or rocks or in large trees, away from nocturnal predators. In daytime, water availability may limit its range in arid areas.[2] It is found throughout southern Africa, ranging from South Africa north to Angola, Zambia, and Mozambique. The subspecies are divided across this range. The Cape chacma is found in southern South Africa; the gray-footed chacma, is present from northern South Africa, through the Okavango Delta in Botswana, Zimbabwe, Mozambique (south of the Zambezi), to southwest Zambia; and the Ruacana chacma is found in northern Namibia and southern Angola.[2]
The chacma baboon is an omnivorous highly opportunistic feeder, and will eat practically anything; typical foods include fruits, seeds, grass, blossoms, bulbs, bark, insects, spiders, worms, grubs, rodents, birds, small antelope and fungi (the desert truffle Kalaharituber pfeilii). Chacma baboon diet is thought to contain about 2 percent animal-sourced food, most of which consists of invertebrates; proportions vary between populations.[15] Baboons are considered vermin by most African farmers due to their foraging of cultivated crops and livestock.[16] At the Cape of Good Hope in particular, chacma baboons are also known for taking shellfish and other small marine invertebrates.[17] It is generally a scavenger when it comes to game meat, and rarely engages in hunting larger animals. One incident of a chacma baboon killing a human infant has been reported, but the event is so rare, the locals believed it was due to witchcraft.[18] Normally, wild chacma baboons will flee at the approach of humans, though this is changing due to the easy availability of food and garbage from human dwellings in villages and towns near the baboons' habitat.[19]
Despite their formidable nature and large size, chacma baboons are vulnerable to a variety of predators.[20] Undoubtedly the main predator of adult chacma baboons overall is the leopard.[21][22] In the Waterberg Biosphere, chacma baboon comprised 20.2% of leopard kills and 18.7% of the leopard's prey biomass.[23] Although previously little documented, the African wild dog, a predator of similar or even slightly inferior size to male baboons themselves, in Mana Pools National Park (Zimbabwe) took to chacma baboons as their main prey, comprising 44% of 118 kills.[24] Less routine predation on chacma baboons has been reportedly committed by lions, spotted hyena, Nile crocodiles and African rock pythons (in rough descending likelihood of threat).[21][25][26][27] The predators of infant and juvenile chacma baboons are probably even more diverse but poorly-documented.[20][21] It is documented that Verreaux's eagles and martial eagles have taken young chacma baboons and probable or possible predation has been committed by other eagles: crowned eagles and tawny eagles.[21][25][28][29] When approaching potentially dangerous sites such as watering holes, more vulnerable members of the chacma baboon group may travel near the rear of the group but may conversely end up by the front of group out of fear if a predator approaches.[30] The adult male chacma baboon has a fearsome defense and may assault their predators with their large, sharp canine teeth, which can at least seriously injure predators as formidable as leopards, and (despite being far from exempt from predation) the adult males tend to be the least vulnerable members of the baboon troops. As in other monkeys, the larger, more formidable male baboons may successfully defend more vulnerable members of the troop via attacking predators if they come into sight.[20][24][31]
The chacma baboon usually lives in social groups, called troops, which are composed of multiple adult males, adult females, and their offspring. Occasionally, however, very small groups form that consist of only a single adult male and several adult females.[32] Chacma troops are characterized by a dominance hierarchy. Female ranking within the troop is inherited through the mother and remains relatively fixed, while the male ranking is often in flux, especially when the dominant male is replaced. Chacmas are unusual among baboons in that neither males nor females form strong relationships with members of the same sex. Instead, the strongest social bonds are often between unrelated adult males and females. Infanticide is much more common among Chacmas compared to most other baboon species, as newly dominant males will often kill infants or young baboons sired by the previously dominant male.[33] Baboon troops possess a complex group behavior and communicate by means of body attitudes, facial expressions, vocalizations and touch.
The chacma baboon often sleeps in large groups on high rocks, cliffs or in tall trees at night to avoid nocturnal predators. The morning dispersal from the sleeping site is synchronized, with all members leaving at the same time. In most cases, dispersal is initiated by a single individual, and the other members of the group decide whether or not to follow. At least five followers must be recruited for a successful dispersal initiation, and not all initiation attempts are successful. Surprisingly, the initiator's dominance status shows little correlation with successful initiation of departure; more-dominant individuals are no more likely to lead a successful departure than subordinate individuals. One study has shown that while the success rate of dispersal initiation attempts is relatively constant across all sexes, male are more likely to attempt initiation than females, and lactating females are less likely to attempt initiation than females without dependent offspring.[35] A separate study has achieved slightly different results. While the dominance hierarchy does not play a significant role in initiating the morning dispersal, social affiliation does. Chacma baboons that play a more central role in the group (as measured by grooming behavior and time spent with other members) are more likely to be followed during the morning dispersal. This study concluded that group members are more likely to follow the behavior of individuals with which they are closely affiliated.[36]
Dominance does play a role in group foraging decisions. A dominant individual (usually the alpha male) leads the group to easily monopolised resources. The group usually follows, even though many subordinate members cannot gain access to that particular resource. As in morning dispersal, the inclination of group members to follow the leader is positively associated with social interactions with that dominant individual.[37]
Collective foraging behaviour, with many individuals taking advantage of the same resource at once, has also been observed. However, this behavior can be chiefly attributed to shared dietary needs rather than social affiliation. Pregnant females, who share similar dietary needs, are more likely to synchronise their behaviour than fertile females. Foraging synchronization decreases in areas with lower food density.[38]
Adoption behaviour has been observed in chacma baboons. Orphaned baboons whose mothers have died or disappeared are often too small to care for themselves. In one study of nine natural orphans and three introduced orphans, all but one orphan were adopted by another member of the troop. The individual that was not adopted was 16 months old, four months older than the next oldest orphan, and was old enough to survive on its own. Adoption behaviour includes sleeping close to the orphaned infant, grooming and carrying the orphan, and protecting it from harassment by other members of the troop. Both males and females care for infants, and care does not depend on the infant's sex. Additionally, nearly all caregivers are pre-reproductive, only four or five years of age. The two major theories explaining this behavior are kin selection, in which caregivers take care of potentially related orphans, and parental practice, in which young baboons increase their own fitness by using an orphan to practice their own parenting skills.[39]
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Males and female chacma baboons often form relationships referred to as "friendships". These cooperative relationships generally occur between lactating females and adult males. The females are believed to seek out male friendships to gain protection from infanticide. In many baboon species, immigrant alpha males often practice infanticide upon arrival in a new troop. By killing unrelated infants, the new male shortens the time until he can mate with the females of the troop. A female with dependent offspring generally does not become sexually receptive until she weans her offspring at around 12 months of age. However, a mother usually becomes sexually receptive shortly after the death of her offspring.[40]
This protection hypothesis is supported by studies of stress hormones in female baboons during changes in the male hierarchy. When an immigrant male ascends to the top of the male dominance hierarchy, stress hormones in lactating and pregnant females increases, while stress hormones in females not at risk of infanticide stay the same. Additionally, females in friendships with males exhibit a smaller rise in stress hormones than do females without male friends.[41]
The benefits of friendship to males are less clear. A male is more likely to enter into friendships with females with which he has mated, which indicates males might enter into friendships to protect their own offspring and not just to protect that female's future reproductive success.[42] These friendships may play a role in the mating system of chacma baboons. A female will often mate with several males, which increases the number of potential fathers for her offspring and increases the chances she will be able to find at least one friend willing to protect her infants and assist in caring for them.[43]
Female chacma baboons have been observed to compete with each other for male friends. This may be the result of one male having a high probability of paternity with multiple females. These competitions are heavily influenced by the female dominance hierarchy, with dominant females displacing subordinate females in friendships with males. Generally, when a more-dominant female attempts to make friends with an individual which is already the friend of a subordinate female, the subordinate female reduces grooming and spatial proximity to that male, potentially leaving her offspring at higher risk of infanticide.[44]
The chacma baboon is widespread and does not rank among threatened animal species. However, in some confined locations, such as South Africa's Southern Cape Peninsula, local populations are dwindling due to habitat loss and predation from other protected species, such as leopards and lions.[45] Many troops have become a suburban menace in their search for food, overturning garbage cans, and literally breaking into cars and houses where they cause much damage. These troops can be dangerous and aggressive, and they will even steal food directly from people. These negative encounters have resulted in the baboons being hunted and poisoned by frustrated local residents. This isolated population is thought to face extinction within 10 years.[19]
The chacma is listed under Appendix II of CITES as it occurs in many protected areas across its range.[2] The only area in South Africa where they are monitored is in the Cape Peninsula, where they are protected.
Observations by those working hands-on in South Africa's rehabilitation centers have found this species is damaged by human intervention; troop structures are influenced, and over the years a significant loss in numbers has occurred. Because they live near and invade human habitats, baboons are regularly shot, poisoned, electrocuted, beaten, run over, and captured for the pet industry, research laboratories and muti (medicine).[46] Despite this, assessors working for the IUCN believe there are no major threats that could result in a range-wide decline of the species.[2]
The chacma baboon (Papio ursinus), also known as the Cape baboon, is, like all other baboons, from the Old World monkey family. It is one of the largest of all monkeys. Located primarily in southern Africa, the chacma baboon has a wide variety of social behaviours, including a dominance hierarchy, collective foraging, adoption of young by females, and friendship pairings. These behaviors form parts of a complex evolutionary ecology. In general, the species is not threatened, but human population pressure has increased contact between humans and baboons. Hunting, trapping, and accidents kill or remove many baboons from the wild, thereby reducing baboon numbers and disrupting their social structure.
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