Population Of Baboons Research Articles

Gastrointestinal parasite prevalence, diversity and association in free-ranging Chacma baboon troops in a semi-arid savanna ecosystem of Zimbabwe

Free-ranging Chacma baboon species are known to harbour a wide range of zoonotic parasites, and their frequent close interactions with humans pose a risk of transmission of zoonotic parasites between the two species. This research study focused on understanding parasite dynamics in free-ranging baboon populations that inhabit human-wildlife interface areas, a case of Gwanda State University's Epoch Mine campus in Filabusi at Insiza district. A descriptive and analytical cross-sectional design was used to investigate the prevalence, diversity and association of gastrointestinal parasites among three baboon troops found at the Epoch Mine campus. One hundred and twenty (120) fresh faecal samples were collected from the three troops between February and September 2023. The centrifugal floatation technique was used to process and analyse faecal samples, and parasite ova and cysts were identified using morphological features like shape and size. The prevalence of the parasite taxa and a chi-squared multiple comparison test was computed. Results showed significant differences among most parasite taxa except Coccidia spp and Entamoeba spp among the three troops. The Shannon–Wiener (H′) index was used to calculate diversity and graphs were utilized to present the association. The Kruskal-Wallis tests showed no significant difference in parasite diversity among the three troops. Although troop-parasite association showed different parasite species for each troop, helminths Strongylid spp. and Schistosoma spp. were highly common across all three troops. Troop 1 and 3 were associated with four parasite taxa, whereas Troop 2 had only three. The study reveals the presence of gastro-intestinal parasites of public health concern, as they are capable of causing diseases in humans and domestic animals. The study, therefore, underscores the importance of understanding parasite-host dynamics in mitigating zoonotic disease transmission and suggests the need to generate baseline data for mitigating zoonotic diseases and maintaining a healthy ecosystem.

Re-evaluating the relationship between female social bonds and infant survival in wild baboons.

Over the past few decades studies have provided strong evidence that the robust links between the social environment, health, and survival found in humans also extend to non-human social animals. A number of these studies emphasize the early life origins of these effects. For example, in several social mammals, more socially engaged mothers have infants with higher rates of survival compared to less socially engaged mothers, suggesting that positive maternal social relationships causally improve offspring survival. Here we show that the relationship between infant survival and maternal sociality is confounded by previously underappreciated variation in female social behavior linked to changes in reproductive state and the presence of a live infant. Using data from a population of wild baboons living in the Amboseli basin of Kenya - a population where high levels of maternal sociality have previously been linked to improved infant survival - we find that infant- and reproductive state-dependent changes in female social behavior drive a statistically significant relationship between maternal sociality and infant survival. After accounting for these state-dependent changes in social behavior, maternal sociality is no longer positively associated with infant survival in this population. Our results emphasize the importance of considering multiple explanatory pathways-including third-variable effects-when studying the social determinants of health in natural populations.

When is microbial strain sharing evidence for transmission?

In humans and other social animals, social partners have more similar microbiomes than expected by chance, suggesting that social contact transfers microorganisms. However, social microbiome transmission can be difficult to identify if social partners also have other traits in common or live in a shared environment. Strain-resolved metagenomics has been proposed as a solution for tracking microbial transmission. Using a fecal microbiota transplant dataset, we show that strain sharing can recapitulate true transmission networks under ideal settings when donor-recipient pairs are unambiguous. However, gut metagenomes from a wild baboon population, where social networks predict compositional similarity, show that strain sharing is also driven by demographic and environmental factors that can override signals of social interactions. We conclude that strain-level analyses provide useful information about microbiome similarity, but other facets of study design, especially longitudinal sampling and careful consideration of host characteristics, are essential for conclusions about the underlying mechanisms.

Wild Baboons Groom Objects with Fur: Implications for Infant Corpse Carrying in Primates?

Nonhuman primates demonstrate great behavioral diversity in their responses to death, yet the most prevalent of these—infant corpse carrying—remains poorly understood. While mothers are the most frequent carriers, corpse carrying can be performed by non-mothers, and heterospecifics’ corpses are also carried. We propose a new hypothesis to explain, in part, non-maternal corpse carrying, the ‘mammalian cues hypothesis,’ and experimentally test it in a population of wild baboons. The mammalian-cues hypothesis argues that evolutionary pressures on maternal responsiveness have created a generalized attraction towards mammalian-typical traits in mammals of both sexes. This attraction may drive interest in inanimate objects (including corpses) that display mammalian cues. To test this, we presented objects that varied in mammalian traits to wild chacma baboons (Papio ursinus) and recorded their behavioral responses. Contrary to our hypothesis, baboons handled all objects (i.e., with or without mammalian traits) for similar lengths of time. However, in partial support of our hypothesis, baboons groomed the objects with fur—even those without any other mammalian traits—and explored them in a less destructive manner. We caution that infant corpse grooming by non-mothers in primates may be indicative of the visual and tactile stimuli the corpse presents rather than an interest in death or a reflection of social bonds.

The temporal and genomic scale of selection following hybridization

Genomic evidence supports an important role for selection in shaping patterns of introgression along the genome, but frameworks for understanding the evolutionary dynamics within hybrid populations that underlie these patterns have been lacking. Due to the clock-like effect of recombination in hybrids breaking up parental haplotypes, drift and selection produce predictable patterns of ancestry variation at varying spatial genomic scales through time. Here, we develop methods based on the Discrete Wavelet Transform to study the genomic scale of local ancestry variation and its association with recombination rates and show that these methods capture temporal dynamics of drift and genome-wide selection after hybridization. We apply these methods to published datasets from hybrid populations of swordtail fish (Xiphophorus) and baboons (Papio) and to inferred Neanderthal introgression in modern humans. Across systems, upward of 20% of variation in local ancestry at the broadest genomic scales can be attributed to systematic selection against introgressed alleles, consistent with strong selection acting on early-generation hybrids. Signatures of selection at fine genomic scales suggest selection over longer time scales; however, we suggest that our ability to confidently infer selection at fine scales is likely limited by inherent biases in current methods for estimating local ancestry from contiguous segments of genomic similarity. Wavelet approaches will become widely applicable as genomic data from systems with introgression become increasingly available and can help shed light on generalities of the genomic consequences of interspecific hybridization.

On the duration of face-to-face contacts

The analysis of social networks, in particular those describing face-to-face interactions between individuals, is complex due to the intertwining of the topological and temporal aspects. We revisit here both, using public data recorded by the sociopatterns wearable sensors in some very different sociological environments, putting particular emphasis on the contact duration timelines. As well known, the distribution of the contact duration for all the interactions within a group is broad, with tails that resemble each other, but not precisely, in different contexts. By separating each interacting pair, we find that the fluctuations of the contact duration around the mean-interaction time follow however a very similar pattern. This common robust behavior is observed on 7 different datasets. It suggests that, although the set of persons we interact with and the mean-time spent together, depend strongly on the environment, our tendency to allocate more or less time than usual with a given individual is invariant, i.e. governed by some rules that lie outside the social context. Additional data reveal the same fluctuations in a baboon population. This new metric, which we call the relation “contrast”, can be used to build and test agent-based models, or as an input for describing long duration contacts in epidemiological studies.

BIODEMOGRAPHY OF AGING, CELEBRATING JAMES W. VAUPEL, PHD

Abstract James W. Vaupel, PhD (1945 – 2022), was an international leader in demography and aging research and a pioneer in the field of biodemography. He was a highly creative researcher and very entrepreneurial in the development of new interdisciplinary research environments. This symposium highlights a few of the biodemographic research areas that Dr. Vaupel has been a catalyst for. Denmark was Dr. Vaupel’s home country during the last third of his life, and Dr. Christensen reports on findings from Danish nationwide genetic-epidemiological studies on twins and the oldest old: familial influence on aging phenotypes, cohort differences in health among the oldest old, associations of early life events with late life health, as well as tongue-in-cheek research on perceived age and teeth. Dr. Alberts discusses the ‘invariant rate of aging’ hypothesis that was developed by Vaupel and others. She presents comparative analyses from multiple nonhuman primate populations showing that, while life expectancy can continue to improve, we probably can’t slow the demographic rate of aging. Dr. Campos presents evidence from a wild baboon population in Kenya that glucocorticoid levels—biological markers of stress responses—are strong prognostic indicators of survival and may be key explanations of life span disparities. Dr. Carey presents key discoveries from large-scale studies involving the Mediterranean fruit fly. These include the slowing of mortality at older ages, context-specific sex mortality differentials, a behavioral biomarker for morbidity, dietary conditions for maximizing lifespan versus reproduction and a stationary population identity whereby life lived equals life left.

Palaeopathological and demographic data reveal conditions of keeping of the ancient baboons at Gabbanat el-Qurud (Thebes, Egypt).

Since predynastic times, baboons (Papio hamadryas and Papio anubis) were important in ancient Egypt for ritual and religious purposes. These species did not occur naturally in Egypt and therefore had to be imported, but little is known about their exact provenance and the conditions in which they were kept through time. Here, we analyse the skeletal remains of a collection of baboon mummies coming from Thebes (Egypt), representing a minimum of 36 individuals, from a palaeopathological and demographic point of view. The pathological cases are described, figured where relevant, and the discussion attempts to understand their aetiology. The prevalence of the different types of deformations and pathologies is compared with that of other captive baboon populations from more or less contemporary (Tuna el-Gebel and Saqqara) or older (predynastic Hierakonpolis) sites. This is combined with observations on the age and sex distribution and the proportion of hamadryas and anubis baboons to draw conclusions about the conditions of keeping, possible breeding on-site, provenance of the animals and the trade routes used for import. As in Tuna el-Gebel and Saqqara, the baboons from Gabbanat el-Qurud suffered from numerous metabolic diseases due to chronic lack of sunlight and an unbalanced diet. This and the demographic data suggest that there was a local breeding population derived from animals captured downstream from the Sudanese Nile Valley (for anubis) and from the Horn of Africa or the southern part of the Arabian Peninsula (for hamadryas). A new series of radiocarbon dates is provided, placing the baboons from Gabbanat el-Qurud between the end of the Third Intermediate Period and the beginning of the Late Period.

Environmental, sex-specific and genetic determinants of infant social behaviour in a wild primate.

Affiliative social bonds are linked to fitness components in many social mammals. However, despite their importance, little is known about how the tendency to form social bonds develops in young animals, or if the timing of development is heritable and thus can evolve. Using four decades of longitudinal observational data from a wild baboon population, we assessed the environmental determinants of an important social developmental milestone in baboons-the age at which a young animal first grooms a conspecific-and we assessed how the rates at which offspring groom their mothers develops during the juvenile period. We found that grooming development differs between the sexes: female infants groom at an earlier age and reach equal rates of grooming with their mother earlier than males. We also found that age at first grooming for both sexes is weakly heritable (h2 = 0.043, 95% CI: 0.002-0.110). These results show that sex differences in grooming emerge at a young age; that strong, equitable social relationships between mothers and daughters begin very early in life; and that age at first grooming is heritable and therefore can be shaped by natural selection.

Early life drought predicts components of adult body size in wild female baboons.

In many taxa, adverse early-life environments are associated with reduced growth and smaller body size in adulthood. However, in wild primates, we know very little about whether, where, and to what degree trajectories are influenced by early adversity, or which types of early adversity matter most. Here, we use parallel-laser photogrammetry to assess inter-individual predictors of three measures of body size (leg length, forearm length, and shoulder-rump length) in a population of wild female baboons studied since birth. Using >2000 photogrammetric measurements of 127 females, we present a cross-sectional growth curve of wild female baboons (Papio cynocephalus) from juvenescence through adulthood. We then test whether females exposed to several important sources of early-life adversity-drought, maternal loss, low maternal rank, or a cumulative measure of adversity-were smaller for their age than females who experienced less adversity. Using the "animal model," we also test whether body size is heritable in this study population. Prolonged early-life drought predicted shorter limbs but not shorter torsos (i.e., shoulder-rump lengths). Our other measures of early-life adversity did not predict variation in body size. Heritability estimates for body size measures were 36%-67%. Maternal effects accounted for 13%-17% of the variance in leg and forearm length, but no variance in torso length. Our results suggest that baboon limbs, but not torsos, grow plastically in response to maternal effects and energetic early-life stress. Our results also reveal considerable heritability for all three body size measures in this study population.

Human-influenced diets affect the gut microbiome of wild baboons

Industrialized diets that incorporate processed foods and are often high in simple sugars and fats and low in fiber have myriad health impacts, many of which may operate via impacts on the gut microbiota. Examining how these diets affect the gut microbiota can be challenging given that lab animal models experience altered environmental contexts, and human studies include a suite of co-varying cultural and environmental factors that are likely to shape the gut microbiota alongside diet. To complement these approaches, we compare the microbiomes of wild populations of olive baboons (Papio anubis) with differential access to human trash high in processed foods, simple sugars, and fats in Rwanda’s Akagera National Park. Baboons are a good model system since their microbiomes are compositionally similar to those of humans. Additionally, this population inhabits a common environment with different social groups consuming qualitatively different amounts of human trash, limiting variation in non-dietary factors. Using 16S rRNA gene amplicon sequencing we find that baboons with unlimited access to human trash have reduced microbial alpha diversity and reduced relative abundances of fiber-degrading taxa such as Ruminococcaceae, Prevotellaceae, and Lachnospiraceae. In contrast, baboons with limited access to human trash have a microbiome more similar to that of baboons with no access to human trash. Our results suggest that while a human-influenced diet high in processed foods, simple sugars, and fats is sufficient to alter the microbiome in wild baboons, there is a minimum threshold of dietary alteration that must occur before the microbiome is substantially altered. We recommend that data from wild primate populations such as these be used to complement ongoing research on diet-microbiome-health interactions in humans and lab animal models.

Feeding ecology of a highland population of hamadryas baboons (Papio hamadryas) at Borena-Sayint National Park, northern Ethiopia.

Studying the diet and feeding behavior of primates is essential to understanding their ecology and designing effective conservation plans. Despite decades of study on the hamadryas baboon (Papio hamadryas) in lowland habitats, little is known about the feeding ecology of this species in highland ecosystems. To address this empirical gap, we tracked temporal changes in vegetation abundance and their relation to the dietary choices of hamadryas baboons in highland habitat at Borena-Sayint National Park (BSNP) in northern Ethiopia. We performed behavioral scan sampling on a focal study band of 21-37 hamadryas baboons over a 12-month period. We found that mature and young leaves were the most abundant plant parts throughout the year, while fruits and flowers were the least abundant, with significant seasonal variation that followed the bimodal pattern of rainfall characteristic of the Ethiopian highlands ecosystem. The annual diet of hamadryas baboons at BSNP consisted mostly of fruits (32.0%) and graminoid blades (21.2%), and included 52 food species across 22 families of plants and three families of animals. Food raided from nearby farms accounted for 8.8% of their diet. The availability of fruits and flowers was positively correlated with their consumption, suggesting that these are preferred foods, whereas graminoid blades, and other leaves, appeared to be less preferred foods. The feeding ecology of hamadryas baboons at BSNP differs considerably from that of lowland populations. The well-studied lowland hamadryas baboons in Awash National Park obtain much of their diet from Acacia species and palm fruit, whereas those at BSNP, where Acacia trees are rare and palms are absent, relied on Olinia rochetiana and Rosa abyssinica for a combined 27% of their annual diet. The reliance of hamadryas baboons at BSNP on cultivated crops for nearly one-tenth of their diet leads to conflict with humans and warrants more detailed study so that this issue can be addressed in conservation plans for the area.

Genome-wide coancestry reveals details of ancient and recent male-driven reticulation in baboons.

Baboons (genus Papio) are a morphologically and behaviorally diverse clade of catarrhine monkeys that have experienced hybridization between phenotypically and genetically distinct phylogenetic species. We used high-coverage whole-genome sequences from 225 wild baboons representing 19 geographic localities to investigate population genomics and interspecies gene flow. Our analyses provide an expanded picture of evolutionary reticulation among species and reveal patterns of population structure within and among species, including differential admixture among conspecific populations. We describe the first example of a baboon population with a genetic composition that is derived from three distinct lineages. The results reveal processes, both ancient and recent, that produced the observed mismatch between phylogenetic relationships based on matrilineal, patrilineal, and biparental inheritance. We also identified several candidate genes that may contribute to species-specific phenotypes.

Early life adversity and adult social relationships have independent effects on survival in a wild primate.

Adverse conditions in early life can have negative consequences for adult health and survival in humans and other animals. What variables mediate the relationship between early adversity and adult survival? Adult social environments represent one candidate: Early life adversity is linked to social adversity in adulthood, and social adversity in adulthood predicts survival outcomes. However, no study has prospectively linked early life adversity, adult social behavior, and adult survival to measure the extent to which adult social behavior mediates this relationship. We do so in a wild baboon population in Amboseli, Kenya. We find weak mediation and largely independent effects of early adversity and adult sociality on survival. Furthermore, strong social bonds and high social status in adulthood can buffer some negative effects of early adversity. These results support the idea that affiliative social behavior is subject to natural selection through its positive relationship with survival, and they highlight possible targets for intervention to improve human health and well-being.

Genetic variance and indirect genetic effects for affiliative social behavior in a wild primate.

Affiliative social behaviors are linked to fitness components in multiple species. However, the role of genetic variance in shaping such behaviors remains largely unknown, limiting our understanding of how affiliative behaviors can respond to natural selection. Here, we employed the "animal model" to estimate environmental and genetic sources of variance and covariance in grooming behavior in the well-studied Amboseli wild baboon population. We found that the tendency for a female baboon to groom others ("grooming given") is heritable (h2 = 0.22 ± 0.048), and that several environmental variables-including dominance rank and the availability of kin as grooming partners-contribute to variance in this grooming behavior. We also detected small but measurable variance due to the indirect genetic effect of partner identity on the amount of grooming given within dyadic grooming partnerships. The indirect and direct genetic effects for grooming given were positively correlated (r = 0.74 ± 0.09). Our results provide insight into the evolvability of affiliative behavior in wild animals, including the possibility for correlations between direct and indirect genetic effects to accelerate the response to selection. As such they provide novel information about the genetic architecture of social behavior in nature, with important implications for the evolution of cooperation and reciprocity.

Population status of the Hamadryas baboon in and around Simien Mountains National Park (SMNP), Ethiopia

ABSTRACT This baseline study was conducted in and around Simien Mountains National Park (SMNP), Ethiopia, with the objective of investigating the population status of the Hamadryas baboon. While Hamadryas baboon populations have been extensively studied in Africa, no such study has been carried out in this extreme southwest area of their range. Within the SMNP, the Hamadryas baboon is primarily found in the southwestern, northern and eastern parts of the park. The total population was estimated using the total count method at three counting sites. Within those three sites ~495 individual Hamadryas baboons were found. The population comprised ~190 adults, 150 sub-adults, 133 juveniles, and 22 infants of indeterminate age. The study was completed in both the dry and the wet season and showed no significant change in the population or population dynamics seasonally, suggesting that the members of this resident population are the primary occupants of these locations. The age and gender diversity results indicated that there were approximately 72 adult males and 117 adult females, together with 63 sub-adult males and 87 sub-adult females, 54 male and 80 female juveniles, and 22 infants during the wet season. The Hamadryas baboon’s overall sex ratio was 1:1.65 males to females for adults, 1:1.36 for sub-adults and 1:1.46 for juveniles. This study can serve as a benchmark for tracking the population status over time and rank their conservation status in this extreme southwestern range for this species.

Transition to siblinghood in a wild chacma baboon population

Transition to siblinghood in a wild chacma baboon population

Stable isotopes reveal the effects of maternal rank and infant age on weaning dynamics in wild chacma baboons

Maternal strategies reflect the trade-off between offspring needs and maternal ability to invest, a concept described by the evolutionary theory of parent–offspring conflict. In mammals this conflict has often been investigated by studying weaning, the transition from maternal milk consumption to dietary independence. An investigation of individual variation in weaning can provide information on the adaptive significance of maternal strategies in relation to social and biological variables. We analysed stable nitrogen isotopes of hair samples collected from 22 mother–infant dyads in a wild population of chacma baboons, Papio ursinus, in conjunction with behavioural data on suckling, to explore the temporal dynamics of weaning, as well as the extent and determinants of individual variation in these dynamics. The weaning pattern suggested by isotope values and behavioural data were congruent. The difference between infant and mother stable nitrogen isotope values decreased faster with age in infants of low-ranking mothers, which suggests a faster progression towards weaning, perhaps due to subordinate females experiencing lower resource availability and so being less able to bear the costs of lactation over prolonged periods. Additionally, within-infant variation in stable nitrogen isotope values showed an increase with age (which was not detectable between infants), potentially highlighting the nutritional costs that weaning imposes on offspring. Our combination of isotope analysis and behavioural data from a wild population provides insight into the evolution of maternal strategies. In particular, it suggests that the quantity of care a mother can provide is affected by her rank, with subordinate females possibly not able to lactate for as long and perhaps benefiting from weaning earlier.

Patterns of predation and meat-eating by chacma baboons in an Afromontane environment

Abstract Meat-eating among non-human primates has been well documented but its prevalence among Afromontane baboons is understudied. In this study we report the predatory and meat-eating behaviours of a habituated group of gray-footed chacma baboons (Papio ursinus griseipes) living in an Afromontane environment in South Africa. We calculated a vertebrate-eating rate of 1 every 78.5 hours, increasing to 58.1 hours when unsuccessful predation attempts were included. A key food source was young antelopes, particularly bushbuck (Tragelaphus scriptus), which were consumed once every 115 observation hours. Similar to other baboon research sites, predations seemed mostly opportunistic, adult males regularly scrounged and monopolised prey, there was no evidence they used an active kill bite, and active sharing was absent. This is the first baboon study to report predation of rock python (Python sebae) eggs and likely scavenging of a leopard (Panthera pardus) kill (bushbuck) cached in a tree. We also describe several scramble kleptoparasitism events, tolerating active defence from antelope parents, and the baboons inhibiting public information about predations. In the latter case, baboons with meat often hid beyond the periphery of the group, reducing the likelihood of scrounging by competitors. This often led to prey carcasses being discarded without being fully exploited and potentially providing resources to scavengers. We also highlight the absence of encounters with numerous species, suggesting the baboons are a key component of several species’ landscapes of fear. Given these findings it seems likely that their ecological role in the Soutpansberg has been undervalued, and such conclusions may also hold for other baboon populations.

Simultaneous analysis of stable and radiogenic strontium isotopes in reference materials, plants and modern tooth enamel

Radiogenic strontium isotopes (87Sr/86Sr) are a useful tool in forensics, ecology, bioarcheology and paleoanthropology allowing investigation of present and past migration and landscape use. The measurement of the 87Sr/86Sr ratio traditionally assumes a constant stable (88Sr/86Sr) isotope ratio. However, some studies indicate that these stable Sr isotopes may display mass-dependent fractionation, suggesting that the 88Sr/86Sr ratio may fingerprint previously unknown dietary and physiological information. Here we present a survey of the variability of δ88Sr values, along with the 87Sr/86Sr ratios, in fourteen reference materials of geological and biological origin using MC-ICPMS. The measurements employ a simple sample-standard bracketing method and zirconium external correction. Comparisons with double-spiked δ88Sr TIMS analyses show a very good agreement (0.014 ‰; n = 10). We then applied this method to explore the fractionation of the 88Sr/86Sr ratio in tooth enamel of mammals from two modern food-chains (Kruger National Park and Western Cape, South Africa), and from modern South African chacma baboon populations. Clear differences in the δ88Sr values are observed between plants and teeth of herbivores (~ −0.26 ‰; n = 5), but the distinction between herbivores and carnivores requires further investigation. Variations between tooth enamel of young and adult baboons suggests that the δ88Sr is a promising indicator of weaning behaviors. Our method implementation and preliminary results highlight the importance of coupled radiogenic and stable Sr isotope determination in extant and extinct vertebrates.