Wild Baboons Research Articles

Why Natural History Is Important to (Primate) Science: A Baboon Case Study

Natural history was the scientific approach used in early primate field studies and through the 1960s. After that, natural history fell out of favor, considered either bad science or not science at all. In my plenary talk at the 2018 IPS Congress in Nairobi, I argued that primate science once again needs natural history. Here, I reprise that argument, illustrating the long and tortuous route that took me to this conclusion. I use information on wild baboons (Papio anubis) from my 47-year field study in Kenya to support my claims. I then explain the historical and current reasons why science, including primate science, needs natural history, particularly in the Anthropocene.

Lifetime Fitness in Wild Female Baboons: Trade-Offs and Individual Heterogeneity in Quality.

Understanding the evolution of life histories requires information on how life histories vary among individuals and how such variation predicts individual fitness. Using complete life histories for females in a well-studied population of wild baboons, we tested two nonexclusive hypotheses about the relationships among survival, reproduction, and fitness: the quality hypothesis, which predicts positive correlations between life-history traits, mediated by variation in resource acquisition, and the trade-off hypothesis, which predicts negative correlations between life-history traits, mediated by trade-offs in resource allocation. In support of the quality hypothesis, we found that females with higher rates of offspring survival were themselves better at surviving. Further, after statistically controlling for variation in female quality, we found evidence for two types of trade-offs: females who produced surviving offspring at a slower rate had longer life spans than those who produced surviving offspring at a faster rate, and females who produced surviving offspring at a slower rate had a higher overall proportion of offspring survive infancy than females who produced surviving offspring at a faster rate. Importantly, these trade-offs were evident even when accounting for (i) the influence of offspring survival on maternal birth rate, (ii) the dependence of offspring survival on maternal survival, and (iii) potential age-related changes in birth rate and/or offspring survival. Our results shed light on why trade-offs are evident in some populations while variation in individual quality masks trade-offs in others.

Comparative study of gastrointestinal parasites from captive and wild olive baboon (<i>Papio anubis</i>)

This study compared the gastrointestinal parasites of captive and wild Olive Baboon (Papio anubis). A total of 15 and 50 fresh faecal samples were collected in both Federal College of Wildlife Management Mini Zoo and Kainji Lake National Park (Borgu Sector). The study covered a period of 5 months (January to May, 2018), the faecal sample were taken to the laboratory for examination using floatation method to determine the prevalence of gastro-intestinal parasites. Out of 65 samples collected, 51(78.46%) were infected with one or more gastrointestinal parasite. The highest prevalence was recorded amongst Baboons in captivity (100%). All the parasites encountered in the different samples were nematodes for both captivity and wild Olive baboons. Parasite ova recovered in captive Baboons are Trichuris trichuria, Ascaris lumbricoides and Haemonchus contortus while that of the wild includes Hookworm spp, A. lumbricoides and Strongyle stercolaris. The study advocates periodic monitoring of the health status of the animals in order to reduce the high prevalence of parasites observed.Keywords: Comparative; olive baboon; gastrointestinal parasites; wild; captive.

Intergenerational effects of early adversity on survival in wild baboons.

Early life adversity can affect an individual's health, survival, and fertility for many years after the adverse experience. Whether early life adversity also imposes intergenerational effects on the exposed individual's offspring is not well understood. We fill this gap by leveraging prospective, longitudinal data on a wild, long-lived primate. We find that juveniles whose mothers experienced early life adversity exhibit high mortality before age 4, independent of the juvenile's own experience of early adversity. These juveniles often preceded their mothers in death by 1 to 2 years, indicating that high adversity females decline in their ability to raise offspring near the end of life. While we cannot exclude direct effects of a parent's environment on offspring quality (e.g., inherited epigenetic changes), our results are completely consistent with a classic parental effect, in which the environment experienced by a parent affects its future phenotype and therefore its offspring's phenotype.

Multi-scale predictors of parasite risk in wild male savanna baboons (Papio cynocephalus)

Several factors are thought to shape male parasite risk in polygynous and polygynandrous mammals, including male-male competition, investment in potentially immunosuppressive hormones, and dispersal. Parasitism is also driven by processes occurring at larger scales, including host social groups and populations. To date, studies that test parasite-related costs of male behavior at all three scales—individual hosts, social groups, and the host population—remain rare. To fill this gap, we investigated multi-scale predictors of helminth parasitism in 97 male savanna baboons (Papio cynocephalus) living in the Amboseli ecosystem in Kenya over a 5-year span. Controlling for multi-scale processes, we found that many of the classic indicators of male mating effort—high dominance rank, testosterone, and glucocorticoids—did not predict helminth infection risk. However, we identified two parasite-related costs associated with male behavior: (i) socially connected males exhibited higher Trichuris trichiura egg counts and greater parasite species richness than socially isolated males and (ii) males with stable group residency exhibited higher parasite species richness than males who frequently dispersed to new social groups. At the population level, males harbored more parasites following periods of drought than rainfall. Lastly, parasites exhibited positive covariance suggesting that infection risk increases if a host already harbors one or more parasite taxa. These results indicate that multi-scale processes are important in driving male parasite risk and that some aspects of male behavior are costly. Together, our results provide an unusually holistic perspective on the drivers of parasite risk in the context of male behaviors and life histories. Infection by gastrointestinal helminths can have major consequences for host fitness, especially in the context of male mating effort. Multi-scale processes—from the host to its social group and population—are important for understanding key drivers of parasitism. We leveraged long-term data from one of the longest running behavioral ecology studies of a wild primate population in the world, the well-studied Amboseli baboon population in Kenya. We found that traditional indicators of male mating effort (attaining high dominance rank, high testosterone and glucocorticoids) did not predict parasitism. However, male social connectedness to females, competitive group demography, and harsh weather were all associated with higher parasitism. Because socially connected males faced the highest parasite risk, males may face a tradeoff between male-female relationships and parasitism. Our results show how processes at multiple scales contribute to variation in male parasite risk.

Sexual selection in the Kinda baboon

Due to wide variation in the presence and degree of expression of a diverse suite of sexually-selected traits, the tribe Papionini represents an outstanding model for understanding how variation in sexual selection pressures and mechanisms leads to trait evolution. Here, we discuss the particular value of Papio as a model genus for studies of sexual selection, emphasizing the presence of multiple mating systems, and differences in the expression of sexually-selected traits among closely-related species. We draw particular attention to the Kinda baboon (Papio kindae), a comparatively less-studied baboon species, by providing a primer to Kinda baboon morphology, genetics, physiology, and behavior. Based on observations of large group sizes, combined with low degrees of sexual dimorphism and large relative testis size relative to other baboon species, we test the hypothesis that Kinda baboons have evolved under reduced direct, and increased indirect, male–male competition. We present the first long-term data on wild Kinda baboons in Zambia. Kinda baboon females show seasonal peaks in births and reproductive receptivity, and males exhibit a queing-rather than contest-based dominance acquisition with long alpha-male tenure lengths. We finish by making a number of explicit testable predictions about Kinda baboon sexual signals and behaviors, and suggest that Kinda baboons have potential to offer new insights into the selective environments that may have been experienced during homininization.

Meat eating in wild hamadryas baboons: Opportunistic trade-offs between insects and vertebrates.

The consumption of meat may provide herbivorous animals with important nutrients that are scarce in their plant-based diet. Seasonal variation in plant food availability has been suggested to motivate dietary flexibility in a range of species and thus primates may seek more prey when key plant resources are unavailable. Alternatively, prey encounter rate may drive meat eating. Here we investigate patterns of meat eating in hamadryas baboons (Papio hamadryas) at Filoha, Awash National Park, Ethiopia. The Filoha baboons rely largely on doum palm fruit (Hyphaene thebaica), which are available most months of the year, and the young leaves of Acacia senegal, which are more abundant during the wet season. We hypothesized that the baboons would consume more meat when H. thebaica and A. senegal were less available, which we tested by comparing meat eating and consumption of these plant food species from March 2005 through February 2006. Our results reveal a high rate of vertebrate meat eating at Filoha (0.028/hour of observation) compared with other hamadryas sites. We found no relationship, however, between meat eating (either insect or vertebrate) and either rainfall or consumption of H. thebaica or A. senegal, indicating that availability of preferred plant resources does not drive meat consumption. Vertebrate consumption and time spent feeding were significantly negatively associated; there was no relationship, however, between the consumption of animal matter and either home range size or daily path length. Vertebrate and insect consumption alternated throughout the year such that the baboons maintained a small amount of animal matter in their diet year-round. Our results suggest that the baboons do not often actively seek animal matter, but consume it opportunistically, with the presence of locust and dragonfly swarms driving insect consumption, and both prey availability and the availability of feeding time shaping vertebrate predation.

How life in a tolerant society affects the usage of grunts: evidence from female and male Guinea baboons

Signals are used to regulate interactions between individuals. To disentangle how motivational disposition, the processing of social information, and the costs and benefits of putative outcomes of interactions affect signalling behaviour, we investigated the usage and function of grunts during approaches in wild Guinea baboons, Papio papio. Guinea baboons live in a tolerant multilevel society with female-biased dispersal, which allowed us to compare their grunt usage to that of other more despotic baboon species. We analysed approaches by female and male Guinea baboons living in the Niokolo Koba National Park, Senegal. When approaching baboons grunted, they were more likely to interact in an affiliative fashion and less likely to displace the partner. In females, the probability of grunting was higher when the relationship strength was low, but only when an infant was present. In males, relationship strength had no impact on the likelihood of grunting during approaches. Rank did not explain variation in grunt probability in females and could not be discerned in males, but males were also more likely to grunt when an infant was near a female partner. We suggest that grunt usage in baboons can be best conceived as a combination of a motivational and a strategic component. The motivational component expresses the increased disposition to interact in an affiliative fashion, while the strategic component refers to the modulation of grunt usage with regard to relationship quality and context. The motivational component appears to be shared between baboon species, while variation in despotism and social organization places different premiums on the benefits of signalling, resulting in variation in grunting patterns between species.

Costs and drivers of helminth parasite infection in wild female baboons.

Helminth parasites can have wide-ranging, detrimental effects on host reproduction and survival. These effects are best documented in humans and domestic animals, while only a few studies in wild mammals have identified both the forces that drive helminth infection risk and their costs to individual fitness. Working in a well-studied population of wild baboons (Papio cynocephalus) in the Amboseli ecosystem in Kenya, we pursued two goals, to (a) examine the costs of helminth infections in terms of female fertility and glucocorticoid hormone levels and (b) test how processes operating at multiple scales-from individual hosts to social groups and the population at large-work together to predict variation in female infection risk. To accomplish these goals, we measured helminth parasite burdens in 745 faecal samples collected over 5years from 122 female baboons. We combine these data with detailed observations of host environments, social behaviours, hormone levels and interbirth intervals (IBIs). We found that helminths are costly to female fertility: females infected with more diverse parasite communities (i.e., higher parasite richness) exhibited longer IBIs than females infected by fewer parasite taxa. We also found that females exhibiting high Trichuris trichiura egg counts also had high glucocorticoid levels. Female infection risk was best predicted by factors at the host, social group and population level: females facing the highest risk were old, socially isolated, living in dry conditions and infected with other helminths. Our results provide an unusually holistic understanding of the factors that contribute to inter-individual differences in parasite infection, and they contribute to just a handful of studies linking helminths to host fitness in wild mammals.

Friend or foe: reconciliation between males and females in wild chacma baboons

Male aggression towards females is a common and often costly occurrence in species that live in bisexual groups. But preferential heterosexual relationships are also known to confer numerous fitness advantages to both sexes—making it of interest to explore how aggression is managed among male–female dyads through strategies like reconciliation (i.e. postconflict affiliative reunions between former opponents). In this study, we build on the traditional postconflict matched-control (PC-MC), time rule and rate methods to validate a novel methodological approach that tests for the presence and form of reconciliation between male and female wild chacma baboons, Papio ursinus. We show that heterosexual opponents exhibit friendly postconflict reunions, further demonstrating that reconciliation occurs almost exclusively between males and pregnant/lactating females who form tight social bonds. Such ‘friendships’ represent stable associations offering proximate and ultimate benefits to both parties—mainly improving (future) offspring survival. This aligns our findings with the ‘valuable relationship hypothesis’, which predicts rates of reconciliation to increase with the fitness consequences of the opponents' bond. Moreover, patterns concerning the initiative to reconcile reveal that males are as likely as females to initiate reconciliation, suggesting that males play a heretofore underappreciated role in maintaining heterosexual friendships. Beyond proposing a multivariate methodological technique applicable to other long-term observational data sets, the present research illuminates how male–female aggression in promiscuous societies may be mitigated via relationship repair strategies like reconciliation, the balance in those efforts between partners shedding new light on the mutual investment in such bonds.

Facial dysplasia in wild forest olive baboons (Papio anubis) in Sebitoli, Kibale National Park, Uganda: Use of camera traps to detect health defects.

Primate populations are in decline, mainly affected by agriculture leading to habitat loss, fragmentation but also chemical pollution. Kibale National Park (Uganda), Sebitoli forest, surrounded by tea and crop fields, is the home range of chimpanzees presenting congenital facial dysplasia. This study aimed to identify to what extent the same phenotypical features are observed in baboons (Papio anubis) of this area. A total of 25390 clips recorded by 14 camera traps between January 2017 and April 2018 were analyzed. We identified 30 immature and adult baboons of both sexes with nose and lip deformities. They were more frequently observed in the northwestern part of the area. A possible effect of pesticides used in crops at the border of their habitat is suspected to alter the embryonic development. This study emphasizes the importance of non-invasive methods to detect health problems in wild primates that can act as sentinels for human health.

Oestrous females avoid mating in front of adult male bystanders in wild chacma baboons.

In social species, female mating strategies can be constrained by both male and female groupmates through sexual conflict and reproductive competition, respectively. This study tests if females adjust their sexual behaviour according to the presence of male and female bystanders in wild chacma baboons (Papio ursinus) and assesses their relative importance. Our results show that oestrous females initiate fewer copulations in the presence of adult male bystanders, irrespective of whether they are mate-guarded or not. This inhibitory effect probably reflects a response to indirect sexual coercion by males, whose close proximity may dissuade females to initiate copulations with rival males to avoid punishment and/or aggressive mating interference. By contrast, females initiate more matings with their mate-guard in the presence of higher-ranking female bystanders, which may reflect an attempt to secure bodyguard services from their mate when they feel threatened. These results emphasize the importance of intra- and intersexual conflicts in shaping female sexual behaviour in this promiscuous society.

Blood Biochemical Reference Intervals for Free-Ranging Olive Baboons (Papio anubis) in Kenya

Biochemical reference intervals are important for assessing the health of target species and populations by identifying abnormalities in key blood parameters. Although reference intervals have been established for baboons in captivity, the lack of data from free-ranging individuals makes it difficult to interpret the results of their blood chemistry panels or to assess and monitor the health of wild baboon populations. The goal of this study was therefore to establish serum biochemical reference intervals for free-ranging olive baboons (Papio anubis) in Kenya. We evaluated 14 biochemical parameters from 28 baboons sampled at the Mpala Research Center, Nanyuki, Kenya. Reference intervals obtained from this wild population were comparable to those from captive baboon populations. Alkaline phosphatase (ALP) and phosphorus levels differed significantly among age classes; both were higher in subadult and juvenile baboons than in adults. However, none of the components of the blood biochemistry panel differed significantly between the sexes. The reference intervals we report provide a baseline for the evaluation and treatment of free-ranging olive baboons and provide context for interpreting the biochemical profiles of captive individuals.

Dominance rank-associated gene expression is widespread, sex-specific, and a precursor to high social status in wild male baboons

In humans and other hierarchical species, social status is tightly linked to variation in health and fitness-related traits. Experimental manipulations of social status in female rhesus macaques suggest that this relationship is partially explained by status effects on immune gene regulation. However, social hierarchies are established and maintained in different ways across species: While some are based on kin-directed nepotism, others emerge from direct physical competition. We investigated how this variation influences the relationship between social status and immune gene regulation in wild baboons, where hierarchies in males are based on fighting ability but female hierarchies are nepotistic. We measured rank-related variation in gene expression levels in adult baboons of both sexes at baseline and in response to ex vivo stimulation with the bacterial endotoxin lipopolysaccharide (LPS). We identified >2,000 rank-associated genes in males, an order of magnitude more than in females. In males, high status predicted increased expression of genes involved in innate immunity and preferential activation of the NF-κB-mediated proinflammatory pathway, a pattern previously associated with low status in female rhesus macaques. Using Mendelian randomization, we reconcile these observations by demonstrating that high status-associated gene expression patterns are precursors, not consequences, of high social status in males, in support of the idea that physiological condition determines who attains high rank. Together, our work provides a test of the relationship between social status and immune gene regulation in wild primates. It also emphasizes the importance of social context in shaping the relationship between social status and immune function.

Comparison of vitamin D metabolites in wild and captive baboons.

Vitamin D adequacy is essential for multiple physiologic processes. With limited exposure to sunlight for vitamin D3 synthesis, captive primates are supplemented with vitamin D3 (cholecalciferol). Vitamin D metabolite data from wild primates living indigenously could suggest optimum levels. The purpose of this study was to: 1) to explore whether baboons, a speciose genus whose members have significant exposed skin, coat color variation and wide geographical distribution, mirrors the skin pigmentation-vitamin D relationship found in humans; 2) compare vitamin D metabolite levels in wild and captive members of the same or similar baboon species; and 3) apply a recently developed method currently used in humans for measuring multiple vitamin D metabolites as a panel to explore if/how these metabolites can inform us on vitamin D sufficiency. Serum samples from males of three baboon species in the wild: Papio anubis (olive baboon, dark exposed skin), P. cynocephalus (yellow baboon, brown exposed skin), and P. hamadryas (hamadryas baboon, pink exposed skin), were compared with vitamin D supplemented captive olive baboons with sun exposure. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) measured vitamin D and its main metabolites. Cholecalciferol, 25 hydroxyvitamin D2&3 (25(OH)D2&3 ), and 24,25 dihydroxyvitamin D2&3 (24,25(OH)2 D2&3 ), showed significant differences by species. The levels of cholecalciferol due to supplements in the captive olive baboons did not convert to higher 25(OH)D3 while the wild olive baboons exhibited the lowest levels for both cholecalciferol and 25(OH)D3 . Further metabolic conversion of 25(OH)D3 to 24,25(OH)2 D3 indicated that all baboons had more similar conversion ratios and these were within the same range found for humans that are depicted as having adequate vitamin D levels. This study provided evidence that exposed skin color does influence vitamin D3 levels, with lower levels in darker skinned species, but these differences are eliminated in the downstream metabolite conversion indicating strong regulatory control.

Greetings in male Guinea baboons and the function of rituals in complex social groups

Ritualized greetings, defined as exchanges of non-aggressive signals, are common among males living in multi-male groups and are thought to balance the trade-offs of male co-residence. While ritualized greetings are widespread in the animal kingdom, the behavioral repertoire described in the genus Papio is exceptional, as it involves potentially harmful behaviors such as genital fondling. Although greetings are one of the most striking male social interactions in baboons, their function is still disputed. We investigated the function of male–male ritualized greeting behavior in wild Guinea baboons. This species lives in multilevel societies where several ‘units’ comprising a primary male, females with young, and occasionally a secondary male form a ‘party’, and two to three parties form a gang. Adult males maintain affiliative relationships with preferred male partners whom they support in coalitions, regardless of kinship. We examined the social behavior of 24 adolescent and adult males (∼900 h focal observations) in the Niokolo-Koba National Park, Senegal, to test whether greetings reflect relationship quality or function to buffer tension. Greetings were ten times more frequent than aggression and twice as frequent as affiliation. Neither dyadic aggression nor tense context predicted greeting rate, discounting the buffering hypothesis. Greetings occurred almost exclusively between males of the same party, even when other parties were around. Within parties, spatially tolerant partners greeted more frequently but dyads did not greet due to proximity prior to the greeting. Although affiliation did not predict overall greeting rate, intense and potentially costly greetings were more likely between males with stronger affiliative relationships. Greetings in Guinea baboons appear to signal commitment among party members, test relationships among spatially tolerant partners, and accentuate relationship strength among highly affiliated males. Although ritualized baboon greetings lack the symbolic component of human rituals, they appear to serve similar functions, specifically to strengthen in-group affiliation and promote cooperation.

Wound healing in wild male baboons: Estimating healing time from wound size.

Wound healing in animals is important to minimize the fitness costs of infection. Logically, a longer healing time is associated with higher risk of infection and higher energy loss. In wild mammals, wounds caused by aggressive intraspecific interactions can potentially have lethal repercussions. Clarifying wounding rate and healing time is therefore important for measuring the severity of the attacks. In addition, impact of secondary damage of wounds (e.g., accidental peeling off of scabs) on heeling time is unknown despite the risk of infection in wild mammals. In baboons, most male injuries have been reported to result from male to male fights. Here, we investigated the relationship between wound size and healing time in wild anubis baboons to clarify the healing cost of physical attacks including secondary damage of wounds. Observations were conducted daily between August 2016 and July 2017 in Kenya for seven adult male anubis baboons. The individual wound rate was one per month on average. In 16 cases, we were able to assess the number of days required for wound healing, and the median healing time was 13 d. Wound healing time was longer for larger wounds. When the scab was peeled off accidentally because of external factors, healing time became longer. One of the causes of scabs’ peeling off was baboons’ scab-picking behavior, and the behaviour was considered self-injurious behavior. However, its predicted healing cost might not be high. We concluded that wounds less than 800 mm2 (the largest observed in this study) in baboon males have little effect on survival. Our results suggest that lethal wounds by physical attacks rarely occur in male baboons, and that healing time and delay caused by secondary damages can be estimated by measuring wound area.

Dietary niches of terrestrial cercopithecines from the Plio-Pleistocene Shungura Formation, Ethiopia: evidence from Dental Microwear Texture Analysis

This study aims to explore the feeding ecology of two terrestrial papionins, Papio and Theropithecus from the Shungura Formation in Ethiopia, the most complete stratigraphic and paleontological record of the African Plio-Pleistocene. Two aspects were evaluated using Dental Microwear Texture Analysis: differences in diet between the extinct genera and their extant relatives, and any potential dietary fluctuations over time. Amongst more than 2,500 cercopithecid dental remains, 154 Theropithecus molars and 60 Papio molars were considered. Thirty-nine extant wild baboons and 20 wild geladas were also considered. The results show that diets of extinct monkeys from Member G already differed between genera as it is the case for their extant representatives. The shearing facets on the Theropithecus molars display significant variations in microwear textures, suggesting several dietary shifts over time. Two events point to higher intakes of herbaceous monocots (tougher than dicots foliages), at about 2.91 Ma (between members B and C) and at 2.32 Ma (between members E and F). These two events are separated by an inverse trend at about 2.53 Ma (between members C and D). Some of these variations, such as between members E and F are supported by the enamel carbon isotopic composition of herbivorous mammals and with paleovegetation evidence.

Antimicrobial Susceptibility Patterns of Escherichia coli Isolated from Olive Baboon ( Papio anubis ) Gut

Background: Antimicrobial resistance is widely acknowledged as a global health problem that has resulted in devastating emerging and re-emerging conditions which are difficult to manage due to limited or unavailable intervention options. It is deepened by the fact that genes encoding for antimicrobial resistance can be transferred horizontally by mobile genetic elements. Escherichia coli is primarily a gut microbial flora in warm-blooded animals including non-human primates that can acquire any of these gene elements from other resistant bacterial strains resulting in their transmission between humans and animals. This study aimed to determine antimicrobial susceptibility of E. coli against commonly used agents as well as production of extended spectrum β-lactamases. Methods: E. coli was isolated from stool samples that were collected from sixty-two captive and sixty-two wild baboons using culture-based methods. The isolates were subjected to fourteen antimicrobial agents followed by characterization of three putative resistance genes; blaCTX-M, blaTEM and blaSHV using polymerase chain reaction. Results: E. coli isolates from both groups of animals were resistant to all antimicrobial agents except Ciprofloxacin. Prevalence of Ampicillin resistance was high in E. coli isolated from both captive (32.3%) and wild (35.5%) baboons. There was higher prevalence of ESBLs in E. coli isolated from wild (17.7%) than captive (14.5%) baboons. Conclusion: As reservoirs of ESBL producing E. coli type, baboons could play a potential role in antibiotic resistant plasmids transmission to the environment and other animals including humans.

Social influences on survival and reproduction: Insights from a long-term study of wild baboons.

For social species, the environment has two components: physical and social. The social environment modifies the individual's interaction with the physical environment, and the physical environment may in turn impact individuals’ social relationships. This interplay can generate considerable variation among individuals in survival and reproduction. Here, I synthesize more than four decades of research on the baboons of the Amboseli basin in southern Kenya to illustrate how social and physical environments interact to affect reproduction and survival.For immature baboons, social behaviour can both mitigate and exacerbate the challenge of survival. Only c. 50% of live‐born females and c. 44% of live‐born males reach the median age of first reproduction. Variation in pre‐adult survival, growth and development is associated with multiple aspects of the social environment. For instance, conspecifics provide direct care and are a major source of social knowledge about food and the environment, but conspecifics can also represent a direct threat to survival through infanticide.In adulthood, both competition (within and between social groups) and cooperative affiliation (i.e. collective action and/or the exchange of social resources such as grooming) are prominent features of baboon social life and have important consequences for reproduction and survival. For instance, adult females with higher social dominance ranks have accelerated reproduction, and adult females that engage in more frequent affiliative social interactions have higher survival throughout adulthood.The early life environment also has important consequences for adult reproduction and survival, as in a number of other bird and mammal species. In seasonal breeders, early life effects often apply to entire cohorts; in contrast, in nonseasonal and highly social species such as baboons, early life effects are more individual‐specific, stemming from considerable variation not only in the early physical environment (even if they are born in the same year) but also in the particulars of their social environment.