Common Name: Chacma Baboon
Scientific Name: Papio ursinus
Family: Cercopithecidae Subfamily: Papio ursinus griseipes, Papio ursinus raucana Genus: Papio Species: P. ursinus Afrikaans: Bobbejaan Xhosa: Imfeme
The Chacma baboon (Papio ursinus ursinus) is also known as the Cape baboon. It is from the Old World Monkey family. The Chacma baboon is amongst the largest and heaviest baboon species and the largest of the monkey family. They are sexually dimorphic, with females being 50-60% of the size of males. Males can weigh from 30-40kg (59-97 pounds) and have a body length of 50-70cm (20-30 inches). Females weigh between 15-20 kg (31-37 pounds) and their body length is 40-60cm (16-24 inches). Baboons can grow up to 120cm tall and their tails are around 2 feet long. Males can have large canine teeth as long as 2 inches.
The Chacma baboon is generally dark brown to grey in colour. It has a long, downward sloping face with close-set eyes under a heavy brow. Baboons walk on all four feet with their tails held in a crooked arch over their back.
Habitat: Chacma baboons inhabit an exceptional wide array of habitats from woodlands, grasslands, acacia scrub and semi-desert habitats including small hills, seaside cliffs and mountains up to 2980m, near to a fresh water source. They spend most of their daylight hours on the ground, but they also forage in trees, and they sleep in trees, cliffs or high rocky outcrops where they are safe from predators.
Distribution: The size of a baboon's home range is dependent on the availability of food and fresh water. In drier areas where baboons cannot use plants for moisture, water supply becomes the over-riding factor
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.
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.
Papio ursinus ursinus – Cape Chacma found in southern South Africa
Papio ursinus griseipes – Gray footed Chacma found in northern South Africa to southern Zambia
Papio ursinus raucana – Ruacana Chacma found from Namibia to southern Angola
The Alpha Male
The troop is led by the most dominant adult male – known as the alpha male. A mature male baboon weighs up to 40kg. He is extremely protective over the female and infants within the troop and jealously guards his right to mate with receptive females when they are at the height of their oestrus cycle. He can be a very tender father to his offspring and a formidable fighter against other males hoping to take over his position in the troop. The males "yawn" to show off their canine teeth to other males and their loud "wahoo" bark is also a form of communicating their strength and social position to others.
Unlike females who typically remain in the same troop their entire lives, males disperse when sexually mature to find unrelated females. When alone, male baboons are called transient or dispersing males. During this period he is alone for long periods of time and is extremely vulnerable without the support of others.
When a dispersing male comes across a new troop, his arrival triggers great displays of "wahooing" with much chasing and vicious fighting. If the new male succeeds in the "take-over", the troops hierarchy is upset and new rivalries and relationships may arise among the females.
Approximately half of most baboon troops are made up of juveniles, so it is normal to see many young in a troop.
Juveniles of similar age tend to hang out together – playing boisterously - so one may get the impression that there are many more than there actually are.
Juveniles act as baby-sitters in the troop, often carrying, handling and playing with the younger, newly weaned babies. They will grab and hide with a youngster should a fight break out among the adult males, even though they are hardly bigger themselves. They take their playing and caring tasks very seriously!
Adult Females and Infants
All adult females go through stages of pink swelling of part of their reproductive cycle. During the peak of the approximate 17 day cycle, she shows a preference to mate with the alpha male. Six months later, she will give birth to a single infant (rarely twins) and will care and nurture her baby with great tenderness. Mom and her new arrival are the focus of the troop, she will be fussed over and groomed constantly by those who want a peek at her newborn. Babies are born with a bright pink face and black fur. They cling to their mother's belly for easy access to milk and protection against the elements. By three months, baby learns to ride mom's back "jockey-style" a fantastic way to get around and see the world. At this stage, they start trying foods such as grass or flowers. They are fully weaned at about one year of age.
Sub-adult baboons are often mistaken as mature animals by the public. Although they are braver and more out-going than the juveniles, they still need the protection of the troop.
Females reach adulthood around five years of age, males on the otherhand are still adolescent at this age. They undergo a rapid growth spurt, resulting in long gangly legs, and a longer snout with a set of pointy canines. Over the next year or two, they will start looking like full grown adult males as their chests and necks fill out and their canines grow long and sharp for the battle ahead.
Reproduction: Generally a female will reproduce once every 2 years. The gestation period is 6 months. The infant will start riding jockey-style when they are about 6 weeks old. By the time they are 4 months old, they are climbing trees and remain very close under the guidance of their mother for about a year.
Social System: Baboons are among the most social and affiliative animals and strong social bonds are fundamental to their lives. As described below, strong social bonds characterized by close proximity and grooming are exceptionally important to female olive, yellow, and chacma baboons. In hamadryas baboons, close social relationships are more important for males - and this pattern apparently characterizes Guinea baboons as well. These patterns of social bonding are closely tied to patterns of dispersal and philopatry that characterize each species, i.e., which sex typically stays in their natal group and which sex leaves to seek reproductive opportunities elsewhere.
Olive baboons, yellow baboons, and chacma baboons live in large social groups or troops, which can be as small as 10-15 individuals and as large as 200 or more. These groups contain both males and females of all ages. The females in these groups are usually philopatric, i.e., they remain in the troop in which they were born and maintain strong social bonds with their female kin. It is these bonds that form the core of a baboon social group: they are the glue holding the troop together and are in fact adaptively beneficial to females (Silk 2007). Males, by contrast, do not typically form strong bonds with other males; rather, they leave their natal troops around puberty and immigrate into a new troop to reproduce, i.e., they disperse. In all but hamadryas baboons, troops generally function as cohesive social units. Troops do, however, sometimes spread out and break up into smaller groups during foraging.
Unlike most other baboons, hamadryas baboons (found in the Horn of Africa and the southwestern Arabian peninsula) have a multi-level social system with four layers of social structure (Kummer 1968a,b, 1984, 1990; Abegglen 1984; Schreier and Swedell 2009). The smallest and most stable social grouping is the one-male unit (OMU), comprising a 'leader male', several females, dependent offspring, and sometimes one or more 'follower' males that socialize with but do not typically mate with the females (Kummer 1968a,b). OMUs comprise 1-9 females, averaging 2-3 females per OMU (Kummer 1968a; Nagel 1973; Swedell 2006). Several OMUs and additional 'solitary' (unaffiliated) males may together form a clan, a spatial and social association within which the male may be close relatives (Abegglen 1984; Colmenares 1992; Schreier and Swedell 2009). The hamadryas social unit analogous to the troops of other (non-hamadryas) baboons described above is the band, which consists of multiple clans that share a common home range, travel pattern, and sleeping site (Kummer 1968a; Abegglen 1984). Finally, the largest social grouping in hamadryas baboons, a temporary aggregation of bands at a sleeping site or foraging area that can number up to 800 individuals, is called a troop (Kummer 1968a).
Less is known about Guinea baboons compared to other baboon species, but they may also be characterized by a multi-level social system. The largest social unit in Guinea baboons is an aggregation at a sleeping site, which consists of several hundred baboons (Sharman, 1981; Anderson and McGrew, 1984). These aggregations subdivide into smaller groupings that appear similar to the clans and OMUs of hamadryas (Dunbar and Nathan 1972; Sharman 1981; Boese 1973, 1975; Galat-Luong et al 2006). Current evidence for Guinea baboons suggests an intermediate social organization between the unstructured multi-male groups of most baboons and the more rigid multi-level societies of hamadryas, with greater flexibility in female behavior compared to hamadryas baboons (Jolly and Phillips-Conroy 2006; Galat-Luong et al 2006).
Bonds Among Females: In most baboons, strong social relationships, or bonds, among female kin form the core of a social group (Seyfarth 1976; Altmann 1980; Strum 1987; Barton et al 1996; Silk et al 1999, 2003, Henzi et al 2000). Females maintain social bonds of varying strengths with different individuals; these bonds are expressed mainly via grooming (whereby the hair is parted and the skin is examined, then debris, insects, or scabs are removed) and they occur preferentially with close relatives (Boese 1975; Seyfarth 1977; Smuts 1985; Barrett et al 1999, 2000, 2002; Bentley-Condit and Smith 1999, 2006a,b; Leinfelder et al 2001; Smith et al 2003). These species are thus characterized as female-bonded, i.e., females remain in their natal groups and form strong social relationships with female kin. These relationships have been shown to be beneficial to females: both yellow and chacma baboon females with stronger social networks experience greater infant survival and even greater longevity (Silk et al. 2003, 2009, 2010).
While less is known about individual social interactions in Guinea baboons, current evidence supports a female bonded social organization for these species as well (Boese 1973). The one exception to the above pattern lies with hamadryas baboons, in which female bonding is reduced due to coercive transfer of females among social units by males (Swedell and Schreier 2009; Swedell et al. in press). Leader males aggressively herd females among OMUs, breaking up female kin groups in the process. Related females, however, do often end up in the same OMU (Sigg et al 1982; Chalyan et al 1994), and the highly variable level of social interaction among female dyads likely reflects variation in kinship among them (Swedell 2002a, 2006.)
Bonds Among Males: Bonds among males also vary among baboon populations and species. Unlike in some other monkeys in which males avoid one another, baboon males do remain together in social groups year-round and are tolerant of one another. Most baboon males are less social than females, however, especially with members of their own sex (Aldrich-Blake et al 1971; Saayman 1971; Davidge 1978a; Smuts 1985), and interactions among males in these species are more likely to be agonistic (involving aggression and submission) than affiliative (involving friendly interactions such as grooming) (Hausfater 1975a). Conflict among males is reduced by formalized dominance relationships, which are essentially power relationships among pairs of males, and males compete over the highest positions in the troop's dominance hierarchy, with the alpha male being able to secure first access to ovulating females.
In hamadryas baboons, by contrast, males groom more with other males, maintain differentiated affiliative relationships, and engage in ritualized greetings called notifications that, for leader males, replace grooming relationships (as males are less tolerant of other males once they acquire females; Abegglen 1984; Colmenares 1990, 1991).
Cross-Sex Bonds in One-Male Groups: Strong affiliative relationships between the sexes, or cross-sex bonds, are usually limited to sexual consortships, exclusive sexual associations between a male and a female (see Reproduction page). However, strong cross-sex bonds occur outside of this context as well, particularly in one-male groups (Byrne et al 1989; Barton et al 1996). Compared to lowland chacma baboons, for example, mountain chacmas are more commonly found in one-male groups, cross-sex bonds are stronger, female-female bonds are weaker, and herding behavior by males (see Male Strategies page) occurs more frequently (Anderson 1981a, 1990; Byrne et al 1987, 1989; Whiten et al 1987; Henzi et al 1990, 1999; Hamilton and Bulger 1992). This suggests a relationship between the one-male group structure and (a) a male's motivation to invest in and defend his females and infants, probably due to increased certainty of paternity of their offspring, and (b) a female's motivation to invest in relationships with the resident male, possibly due to the increased importance of protection against predation and infanticide in a one-male group.
Cross-Sex Bonds in Multi-Male Groups: Affiliative relationships between the sexes occur in multi-male groups as well. In olive, yellow, and chacma baboons, some male-female dyads form grooming relationships, sometimes called friendships, outside of a female's period of estrus or sexual receptivity (see Reproduction page) (Seyfarth 1978b; Altmann 1980; Smuts 1983a, 1985; Byrne et al 1989; Henzi et al 2000). These friendships likely benefit a female via protection for herself and her offspring (Smuts 1983b, 1985; Nguyen et al 2009). The effort devoted by males to maintaining these relationships has been alternately interpreted as mate investment or parental investment, with the relative importance of each factor possibly reflecting differing infanticide risk – and hence cross-sex bonding to counteract this risk – among baboon populations (see Infanticide page) (Smuts 1983b, 1985; Anderson 1992; Palombit et al 1997; Weingrill 2000; Henzi and Barrett 2003).
Foraging: Chacma baboons are omnivorous and opportunistic which means that they will eat almost anything and adapt their diets to the environment in which they live. Their diet is diverse but they are highly selective, preferring foods that are higher in protein. Their diet includes a combination of fruit, flowers, seeds, pods, leaves, gum, sap, roots, corms, rhizomes, tubers and bulbs as well as any small animals that they can catch or come across. With their strength and dexterity, baboons are able to extract undergrown growths which are more difficult for the smaller monkeys to feed on. In the Cape Peninsula of South Africa, baboons also feed on shellfish, including mussels, limpets and crabs.
Diet: The Chacma baboon is omnivorous and may feed on insects, grubs, eggs, chicks, small vertebrates, and invertebrates. The Chacma baboon is generally a scavenger when it comes to game meat and rarely engages in hunting large animals.