At night, the smaller groups coalesce at the sleeping site to form troops of several hundred individuals. Sleeping sites are often located on cliff sides, but hamadryas baboons will also occasionally find shelter in trees. Above all else, these monkeys make sure to find a home near water. The hamadryas baboon is omnivorous; however the majority of its diet consists of plant matter.
Hamadryas baboons in Africa and Arabia share a similar diet to some extent: both populations primarily eat grass seeds, roots, berries, and the flowers, leaves, and pods of acacia trees. Baboon populations in Arabia commonly eat cactus fruit and palm nuts, as well. Non-plant food sources make up a small portion of their diet and include bird eggs, carrion, small mammals, and occasionally insects like locusts. Since most baboons live in arid environments, they are able to survive on low-quality diets for long periods of time in their native habitat.
Hamadryas baboons have a polygynous mating system , where the dominant male mates with more than one female. Within these social groups, called One Male Units OMUs , females bond with males by grooming the male leader of their unit. Females give birth to one baby at a time. For the first 3 weeks of its life, a baby will hold onto its mother by gripping her hair as she moves around. Hamadryas baboon babies have pink skin and black hair until they are one year old, at which point their hair turns brown and resembles that of the adults.
Males begin to establish their own units when they are between 4 and 6 years old, while females begin looking to join an OMU between the ages of 4 and 5. Female members of OMUs may change groups depending on changes in male dominance, which occurs often. Multiple OMUs will often work together forming a group called a band, hence, they "band together" at night to share sleeping sites.
Baboons are some of the world's largest monkeys, and males of different species average from 33 to 82 pounds. Baboon bodies are 20 to 40 inches long, not including substantial tails of varying lengths.
Baboons generally prefer savanna and other semi-arid habitats, though a few live in tropical forests. Like other Old World monkeys, baboons do not have prehensile gripping tails. But they can and do climb trees to sleep, eat, or look out for trouble. They spend much of their time on the ground. Baboons are opportunistic eaters and, fond of crops, become destructive pests to many African farmers.
They eat fruits, grasses, seeds, bark, and roots, but also have a taste for meat. They eat birds, rodents, and even the young of larger mammals, such as antelopes and sheep. Four baboon species i.
These animals form large troops, composed of dozens or even hundreds of baboons, governed by a complex hierarchy that fascinates scientists. Males use shows of physical power to dominate rivals, and troop members spend endless hours carefully grooming one another to remove insects and dead skin. A fifth species, the hamadryas baboon, lives in the hills along the Red Sea coasts of Africa and Arabia.
Getting around Chacma baboons are terrestrial and diurnal, meaning that they spend most of their daylight hours foraging on the ground and in the trees, and at night they sleep in trees or on cliffs where they are safe from predators. Communication Visual A baboon uses facial expressions and body postures to communicate its level of excitement, anger and arousal. Vocal Baboons have a wide range of vocal signals that can be graded into one another and combined with each other and with visual signals in complex and subtle social communication.
Tactile When two individuals meet each other they touch noses as a friendly sign. Habitat Chacma baboons inhabit a wide range of habitats and are common in woodland, savanna, steppes and sub-desert, montane regions of the Drakensberg, Cape Fynbos and Succulent Karoo.
Food Chacma baboons are opportunistic omnivores that feed on a wide range of food items and are able to change their diet relative to what is available in the environment. Social organisation and behaviour Chacma baboons may live in troops of 15 to or more individuals. Sex and life cycles Chacma baboons breed throughout the year. Smart Strategies Chacma baboons have cheek pouches the size of their stomach in which they can store food.
Poorer world without me Chacma baboons play a role in aerating the soils and spreading seeds. People and I Chacma baboons are very interesting animals and they bring delight to people who visit them in zoos or see them in parks or in areas where they still roam freely. Conservation status Chacma baboons are not listed as threatened or endangered.
Relatives The relatives of the chacma baboon Papio ursinus are the Guinea baboon P. Rerefence and further reading Apps, P.
Wild Ways. Field guide to the behaviour of southern African mammals. South Africa. Pahad, G. Social behaviour and crop raiding in chacma baboons of the Suikerbosrand Nature Reserve. Faculty of Science, University of the Witwatersrand, Johannesburg. Hoffman, M. Papio ursinus.
In: IUCN Version Downloaded on Shefferly, N. Skead, C. Historical mammal incidence in the Cape Province. Cape Town. Stuart, C. Field guide to mammals of southern Africa.
Kinda females exhibit small sexual swellings Figure 2 and give inconspicuous calls Petersdorf et al. Chacma females, in contrast, give loud copulation calls, which function to incite male-male competition O'Connell and Cowlishaw, Hamadryas baboons — in contrast to the COKY baboon species described above — live in a multi-level society with reproductive units, called "one male units" comprising one sexually active leader male, a variable number of females, and sometimes a follower male Kummer, Associations between several one-male units constitute a clan Abegglen, ; several clans and unaffiliated bachelor males form a band, the main ecological unit, and multiple bands coalesce at resources, especially sleeping sites, to form troops Schreier and Swedell, Recent behavioral and genetic studies of hamadryas baboons show that leader and follower males tend to be maternally related, in line with the fact that they disperse only rarely.
Guinea baboons also live in a multi-level society. Several units comprising a primary male, 1—6 females, young, and occasional secondary males make up parties, and 2 to 3 parties constitute a gang within a larger community Fischer et al. Male Guinea baboons maintain strong bonds and a high degree of spatial tolerance Fischer et al. Some, but not all males with strong bonds are highly related, suggesting that the existence of kin in the group promotes male tolerance Patzelt et al.
In striking contrast to most other baboon species, aggression between males is so rare that it is not possible to discern a dominance hierarchy with certainty Dal Pesco and Fischer, Males engage in extended ritualized greetings that apparently function to reinforce delineations between parties and to test bonds between males Dal Pesco and Fischer, Females freely transfer between units, parties and gangs.
Female tenure with a given male may vary between weeks and years Goffe et al. Both Guinea and hamadryas baboons exhibit female-biased dispersal Kopp et al.
Note that many of the most significant differences in social behavior between species have been observed across different populations in multiple African sites, as well as in captivity. Thus, there is good evidence that the variation we describe here reflects true species differences and not just variation between populations. Yet, characterizing the variation within species in greater detail would be extremely valuable.
Despite the variation in social organization and aggressiveness between the different baboon species, there is very little variation in the vocal repertoires and call types within the genus Hammerschmidt and Fischer, This suggests that the structure of vocal patterns is highly conserved.
Because species vary in their aggressiveness and their propensity to affiliate, they also differ in the frequency with which they use signals that either relate to fighting ability or "benign intent", respectively Faraut et al. Variation in social organization and in the nature and extent of competition over resources between baboon species is thought to result in differential selective pressure on social cognition Amici et al.
To date, most of the work on baboon social knowledge has been done on chacma baboons that exhibit steep dominance hierarchies known as despotism. A suite of studies by the American primatologists Dorothy Cheney and Robert Seyfarth and colleagues revealed that chacma baboons have sophisticated social knowledge reviewed in Cheney and Seyfarth, For instance, the animals represent the nested hierarchical rank relationships of their group members Bergman, , track the consortship status of pairs in their group Crockford et al.
Field playback experiments revealed that baboon species respond differently to social information. While the territorial chacma baboons respond strongly to apparent intruders Kitchen et al. Similarly, chacma baboons respond strongly to simulated rank reversals Bergman, or break-ups of existing consortships Crockford et al. The somewhat surprising responses of the Guinea baboons may be a result of the high gregariousness of the species, where deviant interaction patterns may initially be classified as "social noise" Faraut and Fischer, In summary, these findings suggest that the content of what is represented, namely the associations between different individuals or their group memberships, appears to be relatively similar across the two species, while the value of different types of social information may vary substantially in relation to the type of society.
Over the past decade, baboon research has provided ground-breaking insights into the relationships between social status, social relationships, health and fitness measures such as offspring survival and longevity. Data from two long-term studies of baboon behavior and life history suggest that sociality enhances the fitness of females.
For example, infants born to yellow baboon females who are more socially integrated have higher survival than infants of less social mothers Archie et al.
As in many other primates, higher-ranking male baboons sire more offspring than other males Altmann et al. Higher-ranking females have shorter periods before they resume menstrual cycling following birth Gesquiere et al. Consistent with this, feeding on crops in olive baboons Higham et al. A number of studies have investigated the proximate mediators of the relationship between behavior and fitness.
In particular, many researchers have taken advantage of non-invasive ways to measure glucocorticoid hormones, a class of hormones known to mediate the energetic demands that accompany social and ecological challenges. Concentrations of glucocorticoid hormones increase during specific challenges that are known to threaten an individual's fitness.
For example, lactating chacma females that were at risk for infanticide because a new male immigrated into the group exhibited elevated glucocorticoid hormones compared to female counterparts that were not at risk Beehner et al.
Additionally, loss of a close female relative increases glucocorticoid concentrations, and this increase may be responsible for initiating a compensatory broadening and strengthening of female grooming networks Engh et al. Several studies have investigated the relationship between glucocorticoid concentrations, rank and social stability in male baboons.
In a long term-study of yellow baboons, high-ranking males had lower glucocorticoid concentrations, regardless of hierarchy stability, while alpha males may experience higher concentrations than expected for their rank Gesquiere et al. Nonetheless, high-ranking yellow baboon males get sick less often and heal from wounds faster, suggesting that these high-ranking males are in better health and do not suffer trade-offs from these extra demands Archie et al.
Higher-ranking chacma baboon males also had higher glucocorticoid concentrations Bergman et al. More recently, baboons were also established as a promising model for studying the impact of sexually transmitted diseases on mating behavior. These findings highlight how pathogens may impose important selective pressures in mate choice and ultimately social evolution.
The addition of data on Kinda and Guinea baboons increases the value of the baboon as a model, as we begin to have data available for all baboon species. While one aim of future analyses will be to understand the sources of variation between species, documenting similarities is equally valuable. Technological developments in genomic sequencing Robinson et al.
Given the close phylogenetic relatedness of the six baboon species, variation in key aspects of social behavior, and the presence of hybrids displaying intermediate phenotypes within hybrid zones, investigation of causal pathways from genotype to phenotype seems particularly promising within the baboon model Bergey et al.
Formerly, research into primate behavioral genetics focused on identifying a few small specific functional polymorphisms in sequence or length, and on linking these to phenotypic variation e. However, such studies are likely to overestimate the effect of one single aspect of genetic variation. With genotyping of single nucleotide polymorphisms SNPs , and whole-genome sequencing, primate field studies are beginning to explore the wider genomic architecture that underlies variation in social behavior Rogers, As well as whole genome sequence data, researchers now have access to annotations for protein coding genes and transcriptomes Robinson et al.
We therefore expect an exponential increase in the number and diversity of available genomes, which will facilitate the investigation of the basis of baboon adaptations and adaptive flexibility. In conjunction with research on other model organisms, such as deer mice Bedford and Hoekstra, , such studies provide fundamental insights into the foundation of natural variation and adaptation in socially living mammals.
Baboons allow us to study the effects of accelerating anthropogenic fragmentation, loss of natural habitats and climate change in a highly adaptable primate system. For example, baboons may rapidly change how long they allocate time and energy to different behaviors or where they range, in response to human-related activities and habitat changes Fehlmann et al.
Studies of individual baboon behavior can use sophisticated GPS tracking and non-invasive genetic tools to make broad-scale inferences about movements and processes at the population level Kopp et al.
These inferences can then be applied to questions of how other large populations of mammals will respond to changes in their environment. Baboons are not considered a global priority in conservation, with the exception of Guinea baboons which are categorized as Near Threatened by the IUCN Oates et al. However, populations geographically overlapping with human communities often damage crops and infrastructure and are persecuted as pests.
In some locations, people consume substantial number of baboons and sell their meat in bushmeat markets e. Humans and baboons often compete for space and hunting of specific individuals or even entire groups is increasingly frequent, leading to fragmented populations and local extinctions Ferreira da Silva et al.
Non-monitored populations living outside protected areas may be at a higher risk of silently disappearing. The challenge is to assess the risk of different populations and develop appropriate conservation plans.
The long-term nature of many baboon field studies has provided great insight into how populations may rise and fall rapidly in response to changes in the environment. The Amboseli Baboon Project, for example, has been running continuously for 50 years, and has documented numerous periods of relative drought or rainfall abundance Alberts et al.
This variation in precipitation has been linked to variation in fecundity and survival Beehner et al. Periods of environmental change, and consequent boom and bust cycles in populations, are driven by both natural phenomena, such as natural aging of woodland, and anthropogenic influences, such as overgrazing by pastoralists Alberts and Altmann, Many long-term baboon field sites also carefully collect detailed data on temperature and rainfall, as well as food availability and diseases. They also monitor the habitats in addition to the baboon populations.
The breadth and scope of such data ensure that the baboon represents an outstanding model of both individual-level and population-level responses to environmental change. Baboons constitute a fascinating and informative analog model for hominin evolution in savanna habitats, with their ongoing patterns of range expansions and contractions, and regular occurrences of hybridization where two species meet.
Given the availability of long-term data and the variation in the types of societies baboons live in, they constitute an excellent test case to study the link between sociality, health, longevity and reproductive success, as well as the emergence and spread of diseases. Such studies are extremely important to put biomedical data from captive baboon studies into natural context. For future research, we propose an approach that integrates field observations and carefully designed field experiments with cutting-edge measures of genomic variation, gene expression, non-invasive endocrinology and immunology.
The fact that baboons have been studied in a wide range of habitats at sites across Africa for several decades also make them an informative example to investigate how populations of large mammals respond to environmental diversity and change see Box 2 for suggested future research questions. How have changes in population density and environmental conditions e.
What is the genetic architecture of baboon social behavior including social style, patterns of dispersal, and degree of reproductive skew according to social status? How does that architecture promote or restrict evolutionary flexibility in social systems?
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