Thore Bergman

Thore Bergman
University of Michigan | U-M · Department of Psychology

Doctor of Philosophy

About

176
Publications
23,240
Reads
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5,336
Citations
Additional affiliations
September 2006 - September 2015
University of Michigan
Position
  • Professor (Assistant)
September 2006 - September 2015
University of Michigan
Position
  • Professor (Associate)

Publications

Publications (176)
Article
Understanding how animals navigate the information landscape is challenging in the wild. Field experiments are a powerful approach to understanding information use and, consequently, cognition in natural settings. Here, we review three types of experiments used to study primate cognition in the wild: 1) presentation experiments that manipulate the...
Article
Female reproductive maturation is a critical life-history milestone, initiating an individual's reproductive career. Studies in social mammals have often focused on how variables related to nutrition influence maturation age in females. However, parallel investigations have identified conspicuous male-mediated effects in which female maturation is...
Article
Full-text available
Primates have adapted to numerous environments and lifestyles but very few species are native to high elevations. Here we investigated high-altitude adaptations in the gelada (Theropithecus gelada), a monkey endemic to the Ethiopian Plateau. We examined genome-wide variation in conjunction with measurements of haematological and morphological trait...
Article
Female reproductive maturation is a critical life-history milestone, initiating an individual's reproductive career. Studies in social mammals have often focused on how variables related to nutrition influence maturation age in females. However, parallel investigations have identified conspicuous male-mediated effects in which female maturation is...
Article
Full-text available
Nonhuman primates are an essential part of tropical biodiversity and play key roles in many ecosystem functions, processes, and services. However, the impact of climate variability on nonhuman primates, whether anthropogenic or otherwise, remains poorly understood. In this study, we utilized age-structured matrix population models to assess the pop...
Article
Selective pressures have favored conspicuous coloration across a wide variety of taxa. A particularly striking example of conspicuous coloration is the brilliant red chest patch of male geladas (Theropithecus gelada), a species of cercopithecine monkey found in the high-altitude regions of Ethiopia. Previous research found that gelada chest patch r...
Article
In 1963, Niko Tinbergen published his foundational manuscript identifying the four questions we ask in animal behavior—how does the behavior emerge across the lifespan (development); how does it work (mechanism); how and why did it evolve (evolution); and why is it adaptive (function). Tinbergen clarified that these ‘levels of analysis’ are complem...
Preprint
Early-life gut microbial colonization is an important process shaping host physiology, immunity and long-term health outcomes in humans and other animals. However, our understanding of this dynamic process remains poorly investigated in wild animals, where developmental mechanisms can be better understood within ecological and evolutionary relevant...
Article
Full-text available
Cognitive ethology explores the ability of animals to flexibly adapt their behavior to rapid physical and social environment fluctuations. Although there is a historical dichotomy between field and captive studies, recently, a growing interest in questions that sit at the intersection of cognitive and adaptive perspectives has helped bridge this di...
Preprint
Full-text available
Survival at high altitude requires adapting to extreme conditions such as environmental hypoxia. To understand high-altitude adaptations in a primate, we assembled the genome of the gelada (Theropithecus gelada), an endemic Ethiopian monkey, and complemented it with population resequencing, hematological, and morphometric data. Unexpectedly, we ide...
Article
Full-text available
Animal communication has long been thought to be subject to pressures and constraints associated with social relationships. However, our understanding of how the nature and quality of social relationships relates to the use and evolution of communication is limited by a lack of directly comparable methods across multiple levels of analysis. Here, w...
Article
The cost–benefit ratio of group living is thought to vary with group size: individuals in ‘optimally sized’ groups should have higher fitness than individuals in groups that are either too large or too small. However, the relationship between group size and individual fitness has been difficult to establish for long-lived species where the number o...
Article
Full-text available
Background Adaptive shifts in gut microbiome composition are one route by which animals adapt to seasonal changes in food availability and diet. However, outside of dietary shifts, other potential environmental drivers of gut microbial composition have rarely been investigated, particularly in organisms living in their natural environments. Result...
Article
The timing of female maturation in wild mammals is often constrained by ecological variables that relate to food acquisition. However, maturational timing in female mammals can also respond to social variables. Specifically, the arrival of novel males can accelerate maturation while the presence of related males can inhibit it. Despite studies on m...
Article
Full-text available
The subspecific taxonomy and distribution of geladas (Theropithecus gelada Rüppell, 1835) remains uncertain. Recent molecular studies based on mitochondrial sequence data revealed a geographically structured, three‐deme population, suggesting that there are three evolutionary units of geladas. However, mitochondrial distributions do not always reco...
Preprint
Full-text available
Animals have evolved numerous strategies to cope with energetic challenges, with dynamic changes to the gut microbiome potentially constituting one such strategy. We tested how proxies of food availability (rainfall) and thermoregulatory stress (temperature) predicted gut microbiome composition of geladas (Theropithecus geladas), a grazing, high-al...
Article
Understanding the relative strength of ecology and phylogeny in shaping parasite communities can inform parasite control and wildlife conservation initiatives while contributing to the study of host species evolution. We tested the relative strengths of phylogeny and ecology in driving parasite community structure in a host whose ecology diverges s...
Preprint
In humans, a controversial hypothesis suggests that father absence promotes early puberty in daughters. Data from rodents confirm females accelerate maturation with exposure to novel males (“Vandenbergh effect”) and delay it with exposure to male relatives. Here, we report the first case of male-mediated maturation in a wild primate, geladas ( Ther...
Article
Multilevel societies (MLSs), stable nuclear social units within a larger collective encompassing multiple nested social levels, occur in several mammalian lineages. Their architectural complexity and size impose specific demands on their members requiring adaptive solutions in multiple domains. The functional significance of MLSs lies in their memb...
Article
Objectives: Human language represents an extreme form of communicative complexity. Primate facial display complexity, which depends upon facial mobility, can be used as a model for the study of the evolution of communicative complexity. The gelada (Theropithecus gelada) is the only primate that can produce a lip-flip eversion. This study investiga...
Article
Across the globe, primates are threatened by human activities. This is especially true for species found in tropical dry forests, which remain largely unprotected. Our ability to predict primate abundance in the face of human activity depends on different species' sensitivities as well as on the characteristics of the forest itself. We studied plan...
Article
The experience of traumatic events can catalyse physiological trade-offs that increase the vulnerability of organisms to disease and death. Among potential sources of trauma, the arrival of new males in female-philopatric species may be particularly salient due to the accompanying threat of infanticide. In such social systems, the killing of depend...
Article
Full-text available
Baboons, members of the genus Papio, comprise six closely related species distributed throughout sub-Saharan Africa and southwest Arabia. The species exhibit more ecological flexibility and a wider range of social systems than many other primates. This article summarizes our current knowledge of the natural history of baboons and highlights directi...
Article
Full-text available
Baboons, members of the genus Papio, comprise six closely related species distributed throughout sub-Saharan Africa and southwest Arabia. The species exhibit more ecological flexibility and a wider range of social systems than many other primates. This article summarizes our current knowledge of the natural history of baboons and highlights directi...
Preprint
Full-text available
Across the globe, primate species and habitats are threatened by human activity. This is especially true for species found in tropical dry forests, which are widely distributed and comprise diverse habitats that remain largely unprotected. Evidence suggests that some primate species endemic to tropical dry forests may be more sensitive to anthropog...
Article
Full-text available
Evolutionary research benefits form the integration of laboratory and field components to determine factors and processes that affect the evolutionary trajectories of species. Our shared interest in understanding hybridization with genetic admixture as a process that may impact social, behavioral, and ecological features of primates, brought us tog...
Article
The origins of speech, the most complex form of animal communication, remain a puzzle. Human speech and nonhuman primate vocalizations have traditionally been viewed dichotomously, with several aspects of speech having no clear analogues in the calls of our primate relatives. The putative unique aspects of speech include a diverse array of learned...
Article
Full-text available
The relatively fixed vocal structure of nonhuman primates stands in stark contrast to humans. However, primate vocal–plasticity studies are particularly limited by ethical and logistic constraints. As an alternative approach, we take advantage of a confirmed howler hybrid zone (Alouatta palliata × A. pigra) to compare the effects of genetic ancestr...
Article
Full-text available
Interspecific hybridization allows the introgression or movement of alleles from one genome to another. While some genomic regions freely exchange alleles during hybridization, loci associated with reproductive isolation do not intermix. In many model organisms, the X chromosome displays limited introgression compared to autosomes owing to the pres...
Article
Full-text available
Several studies show that highly social taxa produce relatively more complex vocalizations. Yet, very few of these cases have demonstrated the function that vocal complexity plays within a highly social setting. Here, we assess potential functions of vocal complexity in male geladas (Theropithecus gelada) living in the Simien Mountains National Par...
Article
Primatologist who gave voice to animal communication and cognition.
Article
The term “baboon” is the common name used for a subset of terrestrial Cercopithecines with large bodies and protruding snouts. Although the application of the term has changed considerably over the years, we argue that common names, such as “baboon,” should reflect the current state of phylogenetic knowledge. This practice promotes a broader unders...
Article
Full-text available
The large-bodied, terrestrial primates in the tribe Papionini are among the most intensely studied animals in the world, yet for some members of this tribe we know comparatively little about their evolutionary history and phylogeography. Geladas (Theropithecus gelada Rüppell, 1835), endemic primates of the Ethiopian highlands, are largely unstudied...
Data
ML tree showing phylogenetic relationships among gelada and baboon haplotypes. Numbers at nodes refer to bootstrap values in %. (PDF)
Data
Bayesian tree showing phylogenetic relationships among gelada and baboon haplotypes. Numbers at nodes refer to posterior probabilities. (PDF)
Data
Best-fit models for protein-coding and non-protein-coding partitions for various gelada populations as obtained from jModeltest for the Bayesian skyline plots (BSPs). (PDF)
Data
Divergence age estimates (Ma) and respective 95% Highest Posterior Density (HPD) intervals. (PDF)
Data
Geographic provenance of gelada samples (decimal degrees), their mtDNA haplotypes (h-type), haplogroups (h-group) and GenBank Accession Numbers. * Sample from northern range but with central haplotype. (PDF)
Data
Selection for the “best” population model. (PDF)
Data
Results of the Automatic Barcode Gap Discovery (ABGD) analyses. (PDF)
Data
Nguyen N, Fashing PJ, Burke RJ. Determining the conservation status of gelada monkeys: Distribution, abundance and phylogenetic relationships of Theropithecus gelada across the Ethiopian Highlands. 2016; Unpubl. Final report to Margot Marsh Biodiversity Foundation. (PDF)
Preprint
Full-text available
The cost-benefit ratio of group-living is thought to vary with group size: individuals in “optimally-sized” groups should have higher fitness than individuals in groups that are either too large or too small. However, the relationship between group size and individual fitness has been difficult to establish for long-lived species where the number o...
Article
Full-text available
Groups of animals (including humans) may show flexible grouping patterns, in which temporary aggregations or subgroups come together and split, changing composition over short temporal scales, (i.e. fission and fusion). A high degree of fission-fusion dynamics may constrain the regulation of social relationships, introducing uncertainty in interact...
Article
Many nonseasonally breeding mammals demonstrate some degree of synchrony in births, which is generally associated with ecological factors that mediate fecundity. However, disruptive social events, such as alpha male replacements, also have the potential to affect the timing of female reproduction. Here, we examined reproductive seasonality in a wil...
Article
Full-text available
Objectives: When closely related species overlap geographically, selection may favor species-specific mate recognition traits to avoid hybridization costs. Conversely, the need to recognize potential same-sex rivals may select for lower specificity, creating the possibility that selection in one domain constrains evolution in the other. Despite a...
Article
Full-text available
All primates show some dietary flexibility, particularly during food shortages. Foods consumed during times of scarcity (i.e., fallback foods) strongly influence the ecology and evolution of a species. Geladas (Theropithecus gelada) eat primarily graminoid leaves (i.e., grasses and sedges), but also consume other diet items (e.g., underground stora...
Article
Full-text available
Despite increasing appreciation for parasitism as an important component of primate ecology and evolution, surprisingly few studies have demonstrated the costs of helminth parasitism in primates. Detecting parasite-related costs in primates is particularly difficult because it requires detailed, long-term data on individual host reproductive succes...
Article
Full-text available
Despite the global distribution and public health consequences of Taenia tapeworms, the life cycles of taeniids infecting wildlife hosts remain largely undescribed. The larval stage of Taenia serialis commonly parasitizes rodents and lagomorphs, but has been reported in a wide range of hosts that includes geladas (Theropithecus gelada), primates en...
Data
Full adapted protocol for the detection of Taenia antigen in dried urine. (DOCX)
Article
Full-text available
In aggressive interactions, game theory predicts that animals should assess an opponent’s condition relative to their own prior to escalation or retreat. Despite the benefits of such mutual assessment, few studies have been able to reject simpler assessment strategies. Here we report evidence for mutual assessment in a wild primate. Gelada (Theropi...
Article
Glucocorticoids are hormones that mediate the energetic demands that accompany environmental challenges. It is therefore not surprising that these metabolic hormones have come to dominate endocrine research on the health and fitness of wild populations. Yet, several problems have been identified in the vertebrate research that also apply to the non...
Article
Full-text available
Accurate data on reproductive parameters are essential for evaluating the adaptive and mechanistic bases of variation within and between species. Here, we combine fecal ovarian hormone analysis with measurements of sex skin swellings and reproductive behavior to describe female reproduction in geladas living in the Simien Mountains National Park, E...
Article
Human speech has many complex spectral and temporal features traditionally thought to be absent in the vocalizations of other primates. Recent explorations of the vocal capabilities of non-human primates are challenging this view. Here, we continue this trend by exploring the spectro-temporal properties of gelada (Theropithecus gelada) vocalization...
Article
Full-text available
Many animals rely on information from vocal signals to assess potential competitors and mates. For example, in primates, males use loud calls to assess rivals when the acoustic properties of the calls reliably indicate the condition or quality of the sender. Here, we investigate whether the loud calls of male geladas (Theropithecus gelada) function...
Conference Paper
Primate vocalizations are generally considered inflexible, although recent evidence suggests some plasticity. Few studies, however, have been able to separate effects of habitat, experience, and genetic ancestry because of the logistic and ethical constraints of working with primates. Hybrid zones provide a unique opportunity to evaluate these fact...
Article
Full-text available
Identifying universal principles underpinning diverse natural systems is a key goal of the life sciences. A powerful approach in addressing this goal has been to test whether patterns consistent with linguistic laws are found in nonhuman animals. Menzerath's law is a linguistic law that states that, the larger the construct, the smaller the size of...
Article
Comparing vocalizations across species is useful for understanding acoustic variation at mechanistic and evolutionary levels. Here, we take advantage of the divergent vocalizations of two closely related howler monkey species (Alouatta pigra and A. palliata) to better understand vocal evolution. In addition to comparing multiple acoustic and tempor...
Article
Life history and socioecological factors have been linked to species-specific patterns of growth across female vertebrates. For example, greater maternal investment in offspring has been associated with more discrete periods of growth and reproduction. However, in primates it has been difficult to test such hypotheses because very few studies have...
Article
Full-text available
Extensive research indicates that inter-sexual selection drives the evolution of complex vocal communication in birds, but parallel lines of evidence are almost entirely absent in mammals. This dearth of evidence, particularly among primates, limits our understanding of the link between sociality and vocal complexity. Here, we use a playback experi...
Article
Full-text available
To successfully navigate their social environments animals need to assess conspecifics. Quality signals and social recognition are 2 assessment strategies that animals employ to evaluate potential rivals or mates. Despite substantial research on both assessment strategies, relatively little work has addressed how quality signals and social recognit...
Article
In one of the first formulations of the social complexity hypothesis, Humphrey (1976, page 316, Growing Points in Ethology, Cambridge University Press) predicts 'that there should be a positive correlation across species between social complexity and individual intelligence'. However, in the many ensuing tests of the hypothesis, surprisingly little...