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a descriptive study of zoonotic disease risk at the human-wildlife interface in a biodiversity hot spot in south western uganda.zoonotic diseases pose a significant health challenge at the human-wildlife interface, especially in sub-saharan africa where ecosystem services contribute significantly to local livelihoods and individual well-being. in uganda, the fragmented forests of hoima district, form part of a biodiversity and emerging infectious disease hotspot composed of communities with high dependency on these wildlife protected areas, unaware of the associated health risks. we conducted a cross-sectional mixed meth ...202133406074
research and conservation in the greater gombe ecosystem: challenges and opportunities.the study of chimpanzees in gombe national park, tanzania, started by jane goodall in 1960, provided pioneering accounts of chimpanzee behavior and ecology. with funding from multiple sources, including the jane goodall institute (jgi) and grants from private foundations and federal programs, the project has continued for sixty years, providing a wealth of information about our evolutionary cousins. these chimpanzees face two main challenges to their survival: infectious disease - including simi ...202033343005
intra-community infanticide in wild, eastern chimpanzees: a 24-year review.infanticide is well documented in chimpanzees and various hypotheses have been proposed to explain this behavior. however, since infanticide by chimpanzees is relatively rare, it has thus far not been possible to thoroughly test these hypotheses. here we present an analysis of the largest dataset of infanticides from a single community of chimpanzees, a full record of all intra-community infanticides and failed attempts at infanticide over a 24-year period for the sonso community of chimpanzees ...202031134473
trabecular bone structure in the distal femur of humans, apes, and baboons.trabecular bone structure has been used to investigate the relationship between skeletal form and locomotor behavior on the premise that trabecular bone remodels in response to loading during an animal's lifetime. the aim of this study is to characterize human distal femoral trabecular bone structure in comparison to three non-human primate taxa and relate the patterns of trabecular structural variation in the distal femur to knee posture during habitual locomotor behavior. a whole-epiphysis app ...202030548834
geographically structured genomic diversity of non-human primate-infecting treponema pallidum subsp. pertenue.many non-human primate species in sub-saharan africa are infected with treponema pallidum subsp. pertenue, the bacterium causing yaws in humans. in humans, yaws is often characterized by lesions of the extremities and face, while t. pallidum subsp. pallidum causes venereal syphilis and is typically characterized by primary lesions on the genital, anal or oral mucosae. it remains unclear whether other t. pallidum subspecies found in humans also occur in non-human primates and how the genomic dive ...202033125317
jaw elevator muscle coordination during rhythmic mastication in primates: are triplets units of motor control?the activity of mammal jaw elevator muscles during chewing has often been described using the concept of the triplet motor pattern, in which triplet i (balancing side superficial masseter and medial pterygoid; working side posterior temporalis) is consistently activated before triplet ii (working side superficial masseter and medial pterygoid; balancing side posterior temporalis), and each triplet of muscles is recruited and modulated as a unit. here, new measures of unison, synchrony, and coord ...202031821998
parasitic infections in african humans and non-human primates.different protozoa and metazoa have been detected in great apes, monkeys and humans with possible interspecies exchanges. some are either nonpathogenic or their detrimental effects on the host are not yet known. others lead to serious diseases that can even be fatal. their survey remains of great importance for public health and animal conservation. fecal samples from gorillas (gorilla gorilla) and humans living in same area in the republic of congo, chimpanzees (pan troglodytes) from senegal an ...202032664573
adenovirus infections in african humans and wild non-human primates: great diversity and cross-species transmission.non-human primates (nhps) are known hosts for adenoviruses (advs), so there is the possibility of the zoonotic or cross-species transmission of advs. as with humans, adv infections in animals can cause diseases that range from asymptomatic to fatal. the aim of this study was to investigate the occurrence and diversity of advs in: (i) fecal samples of apes and monkeys from different african countries (republic of congo, senegal, djibouti and algeria), (ii) stool of humans living near gorillas in ...202032570742
anatomical study of the incisivus labii superioris and inferioris muscles in non-human primates.the facial muscles have significant roles for vocalization, feeding, and facial expression in both human and non-human primates. of these, the anatomy of the incisivus labii superioris (ils) and incisivus labii inferioris (ili), which are considered as the accessory bundle of the orbicularis oris (oo) in humans, has rarely been documented in the literature. our current understanding of the function of the ils and ili is that they probably retract the upper and lower lips. also, there is no accou ...202032420698
prior experience mediates the usage of food items as tools in great apes (pan paniscus, pan troglodytes, gorilla gorilla, and pongo abelii).humans use tools with specific functions to solve tasks more efficiently. however, functional specialization often comes at a cost: it can hinder the production of actions that are not usually performed with those tools, thus resulting in a fixation effect (functional fixedness). little is known about whether our closest living relatives, the nonhuman great apes, are vulnerable to this detrimental effect of experience. we examined whether great apes from 4 species (n = 35) would become fixated o ...202032463250
same space, different species: the influence of exhibit design on the expression of zoo-housed apes' species-typical retiring behaviors.wild chimpanzees frequently make arboreal nests, while wild lowland gorillas typically nest on the ground. we aimed to understand whether zoo-housed apes' use of elevated spaces for retiring similarly differed between species and across exhibits. using a pre-planned exhibit switch at lincoln park zoo (chicago, usa), we compared where (elevated or terrestrial) two groups of apes (pan troglodytes and gorilla gorilla gorilla) performed retiring behaviors (inactive, sleeping, and nest-building behav ...202032408572
variation in behavioral traits of two frugivorous mammals may lead to differential responses to human disturbance.human activities can lead to a shift in wildlife species' spatial distribution. understanding the specific effects of human activities on ranging behavior can improve conservation management of wildlife populations in human-dominated landscapes. this study evaluated the effects of forest use by humans on the spatial distribution of mammal species with different behavioral adaptations, using sympatric western lowland gorilla and central chimpanzee as focal species. we collected data on great ape ...202032313637
food preference and nutrient composition in captive bonobos (pan paniscus).food preference has been studied in a range of hominoidea in the wild and in captivity, allowing for interspecific comparisons. chimpanzees (pan troglodytes) and gorillas (gorilla gorilla gorilla) prefer low-fibre, high-sugar foods, suggesting that frugivory and their dietary overlap are a result of their shared preference for the same nutrients. comparable tests of the nutritional preference of bonobos do not exist. in this study we examined food preferences of five captive bonobos for 23 famil ...202032246408
mandibular corpus shape is a taxonomic indicator in extant hominids.the aim of this study is to understand whether the shape of three sub-regions of the mandibular corpus (the alveolar arch, corpus at m1 and posterior symphysis) are useful for making taxonomic assessments at the genus and species levels in extant hominids.202032166734
no evidence of what-where-when memory in great apes (pan troglodytes, pan paniscus, pongo abelii, and gorilla gorilla).episodic memory is the ability to recollect specific past events belonging to our personal experience, and it is one of the most crucial human abilities, allowing us to mentally travel through time. in animals, however, evidence of what-where-when memory (hereafter, www memory) is limited to very few taxa, mostly reflecting the socioecological challenges faced in their environment. in this article, we aimed to replicate 2 studies previously conducted on birds and primates to find convincing evid ...202032052981
trabecular architecture of the capitate and third metacarpal through ontogeny in chimpanzees (pan troglodytes) and gorillas (gorilla gorilla).chimpanzees (pan troglodytes) and gorillas (gorilla gorilla) both knuckle-walk in adulthood but are known to develop their locomotor strategies differently. using dentally defined age-groups of both pan and gorilla and behavioral data from the literature, this study presents an internal trabecular bone approach to better understand the morphological ontogeny of knuckle-walking in these taxa. capitate and third metacarpal bones were scanned by μct at 23-43 μm resolution with scaled volumes of int ...202031805487
trabecular variation in the first metacarpal and manipulation in hominids.the dexterity of fossil hominins is often inferred by assessing the comparative manual anatomy and behaviors of extant hominids, with a focus on the thumb. the aim of this study is to test whether trabecular structure is consistent with what is currently known about habitually loaded thumb postures across extant hominids.202031762017
human engagement and great ape conservation in africa.despite large investments of funding into great ape conservation in africa, wild populations of gorillas (gorilla ssp), chimpanzees (pan troglodytes ssp) and bonobos (pan paniscus) continue to decline. causes for this decline fall into three broad categories: habitat loss, illegal hunting, and disease. contributing factors to all of these causes are linked to pressure from the expanding human population competing for forest resources. we have moved beyond the time of debating the pros and cons o ...202033170515
meat eating by nonhuman primates: a review and synthesis.most nonhuman primates prey on vertebrates. meat-eating, defined as ingestion of vertebrate tissue, occurs in 12 families, ≥39 genera, and ≥89 species. it is most common in capuchins (cebus and sapajus spp.), baboons (papio spp.), bonobos (pan paniscus), and chimpanzees (pan troglodytes) and modestly common in blue monkeys (cercopithecus mitis), callitrichids (callithrix spp. and saguinus spp.), and squirrel monkeys (saimiri spp.). it is uncommon in other cercopithecines, rare in other haplorhin ...202033137551
comparative anatomy and 3d geometric morphometrics of the el sidrón atlases (c1).the first cervical vertebra (atlas, c1) is an important element of the vertebral column because it connects the cranial base with the cervical column, thus helping to maintain head posture and contributing to neck mobility. however, few atlases are preserved in the fossil record because of the fragility of this vertebra. consequently, only eight well-preserved atlases from adult neandertals have been recovered and described. here, we present nine new atlas remains from the el sidrón neandertal s ...202033137550
demography, life-history trade-offs, and the gastrointestinal virome of wild chimpanzees.in humans, senescence increases susceptibility to viral infection. however, comparative data on viral infection in free-living non-human primates-even in our closest living relatives, chimpanzees and bonobos (pan troglodytes and p. paniscus)-are relatively scarce, thereby constraining an evolutionary understanding of age-related patterns of viral infection. we investigated a population of wild eastern chimpanzees (p. t. schweinfurthii), using metagenomics to characterize viromes (full viral comm ...202032951554
differences in the mutual eye gaze of bonobos (pan paniscus) and chimpanzees (pan troglodytes).eye gaze is widespread in nonhuman primate taxa and important for social cognition and communicative signaling. bonobos and chimpanzees, two closely related primate species, differ in social organization, behavior, and cognition. chimpanzees' eye gaze and gaze following has been studied extensively, whereas less is known about bonobos' eye gaze. to examine species differences using a more ecologically relevant measure than videos or pictures, the current study compared bonobo and chimpanzee mutu ...202032804530
atypically high reproductive skew in a small wild chimpanzee community in a human-dominated landscape.social rank is positively correlated with reproductive success in numerous species, albeit demographic factors often influence those patterns. in multimale primate species, reproductive skew tends to decrease with increasing numbers of males and sexually receptive females. alpha male chimpanzees (pan troglodytes) often sire a disproportionate, though somewhat variable, percentage of offspring compared to other males. in a small community of eastern chimpanzees inhabiting a human-dominated landsc ...202032604094
investigating the function of mutual grooming in captive bonobos (pan paniscus) and chimpanzees (pan troglodytes).social grooming is often exchanged between individuals in many primate species. rates of bidirectional (or simultaneous mutual) grooming vary across primate species, and its function is not yet fully understood. for example, mutual grooming is frequent in chimpanzees but rare in most primate species including wild bonobos. there are, however, no quantitative data available in captive bonobos. therefore, through the direct comparison between captive bonobos and chimpanzees, this study aimed to (i ...202032229727
the hla a03 supertype and several pan species major histocompatibility complex class i a allotypes share a preference for binding positively charged residues in the f pocket: implications for controlling retroviral infections.the major histocompatibility complex (mhc) class i region of humans, chimpanzees (pan troglodytes), and bonobos (pan paniscus) is highly similar, and orthologues of hla-a, -b, and -c are present in both pan species. based on functional characteristics, the different hla-a allotypes are classified into different supertypes. one of them, the hla a03 supertype, is widely distributed among different human populations. all contemporary known chimpanzee and bonobo mhc class i a allotypes cluster genet ...202032075930
altruistic food sharing behavior by human infants after a hunger manipulation.altruistic behavior entails giving valuable benefits to others while incurring a personal cost. a distinctively human form of altruistic behavior involves handing nutritious food to needy strangers, even when one desires the food. engaging in altruistic food transfer, instead of keeping the food, is costly, because it reduces the caloric intake of the benefactor vis-à-vis the beneficiary. human adults engage in this form of altruistic behavior during times of war and famine, when giving food to ...202032019998
ontogenetic insights into the significance of mandibular corpus shape variation in hominoids: developmental covariation between m2 crypt formation and corpus shape.here, we quantify and compare the cross-sectional shape of the mandibular corpus between m1 and m2 during growth in pan paniscus, pan troglodytes, and pongo pygmaeus. the goal is to assess the hypothesis that the shape of the corpus is influenced by the development of permanent molars in their crypts, by examining ontogenetic changes in corpus shape and investigating covariation between corpus shape and m2 and m3 molar crypt forms.202031710703
open-access platform to synthesize knowledge of ape conservation across sites.despite the large body of literature on ape conservation, much of the data needed for evidence-based conservation decision-making is still not readily accessible and standardized, rendering cross-site comparison difficult. to support knowledge synthesis and to complement the iucn ssc ape populations, environments and surveys database, we created the a.p.e.s. wiki (https://apeswiki.eva.mpg.de), an open-access platform providing site-level information on ape conservation status and context. the ai ...202033169878
age-related changes in chimpanzee (pan troglodytes) cognition: cross-sectional and longitudinal analyses.chimpanzees are the species most closely related to humans, yet age-related changes in brain and cognition remain poorly understood. the lack of studies on age-related changes in cognition in chimpanzees is particularly unfortunate in light of the recent evidence demonstrating that this species naturally develops alzheimer's disease (ad) neuropathology. here, we tested 213 young, middle-aged, and elderly captive chimpanzees on the primate cognitive test battery (pctb), a set of 13 tasks that ass ...202033169860
unpacking chimpanzee (pan troglodytes) patch use: do individuals respond to food patches as predicted by the marginal value theorem?the marginal value theorem is an optimal foraging model that predicts how efficient foragers should respond to both their ecological and social environments when foraging in food patches, and it has strongly influenced hypotheses for primate behavior. nevertheless, experimental tests of the marginal value theorem have been rare in primates and observational studies have provided conflicting support. as a step towards filling this gap, we test whether the foraging decisions of captive chimpanzees ...202033118192
a machine learning approach to infant distress calls and maternal behaviour of wild chimpanzees.distress calls are an acoustically variable group of vocalizations ubiquitous in mammals and other animals. their presumed function is to recruit help, but there has been much debate on whether the nature of the disturbance can be inferred from the acoustics of distress calls. we used machine learning to analyse episodes of distress calls of wild infant chimpanzees. we extracted exemplars from those distress call episodes and examined them in relation to the external event triggering them and th ...202033094407
human caregivers are integrated social partners for captive chimpanzees.in a captive environment, it is challenging to ensure the highest level of social and psychological well-being for species with naturally complex social organizations and structures. there is a growing need to meet the social requirements for individuals of these species, especially chimpanzees, housed in zoos, sanctuaries, rehabilitation centers, and laboratories. complex social interactions and broader social structures can be aptly described via social network analysis. we expand on the liter ...202033034790
community-based conservation and chimpanzee research in gishwati forest, rwanda.as great ape populations around the world continue to decline, largely due to anthropogenic activities, conservation programs aimed at supporting these efforts have had mixed success. here, we evaluate our community-based conservation program in gishwati forest, rwanda, aimed at helping to restore biodiversity and ecosystem services using chimpanzees as a flagship species. we examine the effectiveness of this program on reducing one of the ongoing threats to gishwati's population of chimpanzees, ...202033016499
chimpanzees use least-cost routes to out-of-sight goals.while the ability of naturally ranging animals to recall the location of food resources and use straight-line routes between them has been demonstrated in several studies [1, 2], it is not known whether animals can use knowledge of their landscape to walk least-cost routes [3]. this ability is likely to be particularly important for animals living in highly variable energy landscapes, where movement costs are exacerbated [4, 5]. here, we used least-cost modeling, which determines the most effici ...202033007243
wild meat hunting and use by sedentarised baka pygmies in southeastern cameroon.as a result of sedentarisation many baka pygmies have changed their mobility patterns away from nomadic lifestyles to living in roadside villages. these settled groups are increasingly dependent on cultivated foods but still rely on forest resources. the level of dependence on hunting of wild animals for food and cash, as well as the hunting profiles of sedentarised pygmy groups is little known. in this study we describe the use of wild meat in 10 baka villages along the djoum-mintom road in sou ...202032995086
urine as a high-quality source of host genomic dna from wild populations.the ability to generate genomic data from wild animal populations has the potential to give unprecedented insight into the population history and dynamics of species in their natural habitats. however, for many species, it is impossible legally, ethically or logistically to obtain tissue samples of quality sufficient for genomic analyses. in this study we evaluate the success of multiple sources of genetic material (faeces, urine, dentin and dental calculus) and several capture methods (shotgun, ...202032985084
comparative morphology of the corpus callosum across the adult lifespan in chimpanzees (pan troglodytes) and humans.the human corpus callosum exhibits substantial atrophy in old age, which is stronger than what would be predicted from parallel changes in overall brain anatomy. to date, however, it has not been conclusively established whether this accentuated decline represents a common feature of brain aging across species, or whether it is a specific characteristic of the aging human brain. in the present cross-sectional study, we address this question by comparing age-related difference in corpus callosum ...202032978976
urinary cortisol increases during a respiratory outbreak in wild chimpanzees.in mammals, the excretion of cortisol can provide energy toward restoring homeostasis and is a major component of the stress response. however, chronically elevated cortisol levels also have suppressive effects on immune function. as mounting an immune response is energetically costly, sick individuals may conserve energy by exhibiting certain sickness behaviors, such as declining activity levels. due to the complex interplay between immune function and sickness behaviors, endocrinological corre ...202032974394
asymmetry in the cytoarchitecture of the area 44 homolog of the brain of the chimpanzee pan troglodytes.the evolution of the brain in apes and man followed a joint pathway stemming from common ancestors 5-10 million years ago. however, although apparently sharing similar organization and neurochemical properties, association areas of the isocortex remain one of the cornerstones of what sets humans aside from other primates. brodmann's area 44, the area of broca, is known for its implication in speech, and thus indirectly is a key mark of human uniqueness. this latero-caudal part of the frontal lob ...202032973465
stability of chimpanzee (pan troglodytes) urinary reproductive hormones during long-term preservation on filter paper.urine contains multiple water-soluble hormones, which are valuable non-invasive biomarkers for the monitoring of reproductive status and health. an effective method for drying urine on filter paper was previously developed to preserve wildlife urine samples where electrical equipment was not available for this; however, the stability of samples preserved in this way remains to be verified. here, we developed and validated a method to elute multiple water-soluble reproductive hormones from filter ...202032955646
age-associated epigenetic change in chimpanzees and humans.methylation levels have been shown to change with age at sites across the human genome. change at some of these sites is so consistent across individuals that it can be used as an 'epigenetic clock' to predict an individual's chronological age to within a few years. here, we examined how the pattern of epigenetic ageing in chimpanzees compares with humans. we profiled genome-wide blood methylation levels by microarray for 113 samples from 83 chimpanzees aged 1-58 years (26 chimpanzees were sampl ...202032951551
faecal parasites increase with age but not reproductive effort in wild female chimpanzees.energy investment in reproduction is predicted to trade off against other necessary physiological functions like immunity, but it is unclear to what extent this impacts fitness in long-lived species. among mammals, female primates, and especially apes, exhibit extensive periods of investment in each offspring. during this time, energy diverted to gestation and lactation is hypothesized to incur short and long-term deficits in maternal immunity and lead to accelerated ageing. we examined the rela ...202032951547
healthy cardiovascular biomarkers across the lifespan in wild-born chimpanzees (pan troglodytes).chimpanzees (pan troglodytes) are a crucial model for understanding the evolution of human health and longevity. cardiovascular disease is a major source of mortality during ageing in humans and therefore a key issue for comparative research. current data indicate that compared to humans, chimpanzees have proatherogenic blood lipid profiles, an important risk factor for cardiovascular disease in humans. however, most work to date on chimpanzee lipids come from laboratory-living populations where ...202032951545
evaluating the impact of physical frailty during ageing in wild chimpanzees (pan troglodytes schweinfurthii).while declining physical performance is an expected consequence of ageing, human clinical research has placed increasing emphasis on physical frailty as a predictor of death and disability in the elderly. we examined non-invasive measures approximating frailty in a richly sampled longitudinal dataset on wild chimpanzees. using urinary creatinine to assess lean body mass, we found moderate but significant declines in physical condition with age in both sexes. while older chimpanzees spent less of ...202032951544
environmental variability supports chimpanzee behavioural diversity.large brains and behavioural innovation are positively correlated, species-specific traits, associated with the behavioural flexibility animals need for adapting to seasonal and unpredictable habitats. similar ecological challenges would have been important drivers throughout human evolution. however, studies examining the influence of environmental variability on within-species behavioural diversity are lacking despite the critical assumption that population diversification precedes genetic div ...202032934202
similar patterns of genetic diversity and linkage disequilibrium in western chimpanzees (pan troglodytes verus) and humans indicate highly conserved mechanisms of mhc molecular evolution.many species are threatened with extinction as their population sizes decrease with changing environments or face novel pathogenic threats. a reduction of genetic diversity at major histocompatibility complex (mhc) genes may have dramatic effects on populations' survival, as these genes play a key role in adaptive immunity. this might be the case for chimpanzees, the mhc genes of which reveal signatures of an ancient selective sweep likely due to a viral epidemic that reduced their population si ...202032933484
cell type-dependent escape of capsid inhibitors by simian immunodeficiency virus sivcpz.pandemic human immunodeficiency virus type 1 (hiv-1) is the result of the zoonotic transmission of simian immunodeficiency virus (siv) from the chimpanzee subspecies pan troglodytestroglodytes (sivcpzptt). the related subspecies pan troglodytesschweinfurthii is the host of a similar virus, sivcpzpts, which did not spread to humans. we tested these viruses with small-molecule capsid inhibitors (pf57, pf74, and gs-ca1) that interact with a binding groove in the capsid that is also used by cpsf6. w ...202032907979
reproducibility of leftward planum temporale asymmetries in two genetically isolated populations of chimpanzees (pan troglodytes).once considered a hallmark of human uniqueness, brain asymmetry has emerged as a feature shared with several other species, including chimpanzees, one of our closest living relatives. most notable has been the discovery of asymmetries in homologues of cortical language areas in apes, particularly in the planum temporale (pt), considered a central node of the human language network. several lines of evidence indicate a role for genetic mechanisms in the emergence of pt asymmetry; however, the gen ...202032900313
personality, cognition and behavior in chimpanzees: a new approach based on eysenck's model.personality has been linked to individual variation in interest and performance in cognitive tasks. nevertheless, this relationship is still poorly understood and has rarely been considered in animal cognition research. here, we investigated the association between personality and interest, motivation and task performance in 13 sanctuary chimpanzees (pan troglodytes) housed at fundació mona (spain). personality was assessed with a 12-item questionnaire based on eysenck's psychoticism-extraversio ...202032874782
morphomap: an r package for long bone landmarking, cortical thickness, and cross-sectional geometry mapping.this study describes and demonstrates the functionalities and application of a new r package, morphomap, designed to extract shape information as semilandmarks in multiple sections, build cortical thickness maps, and calculate biomechanical parameters on long bones.202032865237
assessing thoraco-pelvic covariation in homo sapiens and pan troglodytes: a 3d geometric morphometric approach.understanding thoraco-pelvic integration in homo sapiens and their closest living relatives (genus pan) is of great importance within the context of human body shape evolution. however, studies assessing thoraco-pelvic covariation across hominoidea species are scarce, although recent research would suggest shared covariation patterns in humans and chimpanzees but also species-specific features, with sexual dimorphism and allometry influencing thoraco-pelvic covariation in these taxa differently.202032864759
a comprehensive analysis of chimpanzee (pan troglodytes)-specific aluyb8 element.alu elements are most abundant retrotransposons with > 1.2 million copies in the primate genome. aluyb8 subfamily was diverged from aluy lineage, and has accumulated eight diagnostic mutations and 7-bp duplication during primate evolution. a total of 1851 aluyb copies are present in the human genome, and most of them are human-specific. on the other hand, only a few aluyb8 copies were identified in the chimpanzee genome by previous studies on aluyb8. the significantly different number of species ...202032860627
validation and utility of a body condition scoring system for chimpanzees (pan troglodytes).obesity is a problem in captive chimpanzee colonies that can lead to increased risk for disease; therefore, implementation of effective weight management strategies is imperative. to properly implement a weight management program, captive managers should be able to noninvasively identify and assess overweight or obese individuals. traditional means of categorizing obese individuals involve sedating the animals to obtain body weights or skin fold measurements. the current study aimed to validate ...202032856319
locking plate femur fracture repair in a juvenile western chimpanzee (pan troglodytes verus) in sierra leone.this case reports the successful management of a traumatic diaphyseal femoral fracture in an infant western chimpanzee (pan troglodytes verus) from a rescue centre in sierra leone using a 2.4-mm intramedullary pin and two 2.7-mm string of pearls™ locking plates. locking plate use has not been previously described in chimpanzees.202032779224
enamel thickness variation in the deciduous dentition of extant large-bodied hominoids.enamel thickness features prominently in hominoid evolutionary studies. to date, however, studies of enamel thickness in humans, great apes, and their fossil relatives have focused on the permanent molar row. comparatively little research effort has been devoted to tissue proportions within deciduous teeth. here we attempt to fill this gap by documenting enamel thickness variation in the deciduous dentition of extant large-bodied hominoids.202032767577
how isotopic signatures relate to meat consumption in wild chimpanzees: a critical reference study from taï national park, côte d'ivoire.the roots of human hunting and meat eating lie deep in our evolutionary past shared with chimpanzees (pan troglodytes). from the few habituated wild populations, we know that there is considerable variation in the extent to which chimpanzees consume meat. expanding our knowledge of meat eating frequencies to more, yet unhabituated, populations requires noninvasive, indirect quantitative techniques. we here evaluate the use of stable isotopes to reconstruct meat-eating behavior in wild chimpanzee ...202032683168
does facial hair greying in chimpanzees provide a salient progressive cue of aging?the greying of human head hair is arguably the most salient marker of human aging. in wild mammal populations, greying can change with life history or environmental factors (e.g., sexual maturity in silverback gorillas). yet, whether humans are unique in our pattern of age-related hair depigmentation is unclear. we examined the relationship between pigmentation loss in facial hair (greying) to age, population, and sex in wild and captive chimpanzees (pan troglodytes). digital facial photographs ...202032663207
age at first molar emergence in pan troglodytes verus and variation in the timing of molar emergence among free-living chimpanzees.age at lower first molar (m1) emergence is a commonly used proxy for inferring life-history scheduling in fossil primates, but its utility is dependent on knowing to what extent extant populations vary in this datum and how this variation correlates with the scheduling of life-history variables. here, we address the first of these issues among extant chimpanzees. while age at m1 emergence has been documented in several live individuals from the kanyawara population of pan troglodytes schweinfurt ...202032652259
a comparison of fecal sampling and direct feeding observations for quantifying the diet of a frugivorous primate.both observational and indirect evidence are widely used to determine the diets of wild animals. direct observations are often assumed to provide the most comprehensive reflection of diet, but many wild animals are logistically challenging to observe. despite the regular use of observational and indirect methods for inferring diet in wild animals, they have rarely been compared in detail for the same study population. over 12 months this study assessed the congruence of methods in estimating the ...202032617082
zoonotic abbreviata caucasica in wild chimpanzees (pan troglodytes verus) from senegal.abbreviata caucasica (syn. physaloptera mordens) has been reported in human and various non-human primates including great apes. the identification of this nematode is seldom performed and relies on egg characterization at the coproscopy, in the absence of any molecular tool. following the recovery of two adult females of a. caucasica from the feces of wild senegalese chimpanzees, morphometric characteristics were reported and new data on the width of the esophagus (0.268-0.287 mm) and on the cu ...202032605080
chimpanzee (pan troglodytes schweinfurthii) population spans multiple protected areas in the albertine rift.we used mitochondrial dna to examine gene flow in a region of western uganda that has received little attention regarding chimpanzee population dynamics. the area is critical to gene flow between isolated democratic republic of congo populations and the rest of east africa. none of the chimpanzees in each of the 4 protected areas under consideration (toro-semliki wildlife reserve, semuliki national park, rwenzori mountains national park and itwara central forest reserve) are fully habituated. th ...202032599590
development of bed-building behaviors in captive chimpanzees (pan troglodytes): implication for critical period hypothesis and captive management.wild great apes build beds for sleeping by combining tree branches or other vegetation, but the development of this behavior is poorly understood. we investigated the development of bed-building behaviors by conducting complementary cross-sectional and longitudinal studies of captive chimpanzees. in the cross-sectional study, we created an ethogram of behaviors related to bed-building by observing 59 chimpanzees living at the kumamoto sanctuary, kyoto university, and the kyoto city zoo. in the l ...202032596775
brunner's gland hyperplasia in a geriatric chimpanzee (pan troglodytes), an infrequently reported lesion.benign duodenal tumours have very rarely been reported in captive non-human primates and are also rare in human beings. brunner's gland hyperplasia has not been fully described in a non-human primate. here, we report brunner's gland hyperplasia in a geriatric chimpanzee, which was an incidental finding during post-mortem examination.202032584460
comparisons of activity budgets, interactions, and social structures in captive and wild chimpanzees (pan troglodytes).chimpanzees in zoos with sufficient and appropriate environmental enrichment devices are expected to exhibit behaviors, interactions, and societies similar to those in the wild. in this study, we compared the activity budgets of each observed behavior, characteristics of social grooming, and social networks of captive chimpanzees at tama zoological park (tama) with those of wild chimpanzees at mahale mountains national park, tanzania (mahale), and tested our predictions. we surveyed 16 chimpanze ...202032575533
consumer perceptions and reported wild and domestic meat and fish consumption behavior during the ebola epidemic in guinea, west africa.the handling, capturing, butchering, and transportation of wildmeat can increase the risk of zoonoses, including the ebola virus disease (evd). guinea, west africa, experienced a catastrophic outbreak of evd between 2013 and 2016. this study aimed to understand local people's sources of information concerning evd, their perceptions of potential wildlife carriers of evd and their meat and fish consumption behavior during this period. a semi-structured questionnaire was administered to 332 partici ...202032566394
the relationship between food calling and agonistic behaviour in wild chimpanzees.a number of social animals produce food-associated calls, which have been interpreted as informative and referential about the quality or quantity of food accessed by the caller. in chimpanzees, however, some behavioural patterns have remained unexplained by this model, suggesting that food-associated calls have a more generalized social function beyond attracting others to food, such as promoting tolerance between co-feeding individuals. in this study, we investigated how wild chimpanzees (pan ...202032561234
hyperglycemic hyperosmolar state in a chimpanzee (pan troglodytes).a 19-year-old female chimpanzee (pan troglodytes) presented for cachexia, acute weakness, hyporexia, icterus, and polyuria. the animal was diagnosed with a hyperglycemic hyperosmolar state, which is a well-recognized syndrome in diabetic humans that is rarely diagnosed in animals. this case documents an important and likely under-reported syndrome in non-human primates.202032542742
developing ancestry informative marker panel for nigeria- cameroonian chimpanzees.chimpanzees (pan troglodytes), with a dwindling population size, are distributed across sub-saharan africa. they are classified into two biogeographical clusters comprising of four subspecies: a western african cluster that includes p. t. verus and p. t. ellioti and a central/eastern african cluster that includes p. t. troglodytes and p. t. schweinfurthii. while the genetic distinctness of nigeria-cameroonian chimpanzees (p. t. ellioti) from western chimpanzees has been known for a while, the fi ...202032529982
discovery of os cordis in the cardiac skeleton of chimpanzees (pan troglodytes).cardiovascular diseases, especially idiopathic myocardial fibrosis, is one of the most significant causes of morbidity and mortality in captive great apes. this study compared the structure and morphology of 16 hearts from chimpanzees (pan troglodytes) which were either healthy or affected by myocardial fibrosis using x-ray microtomography. in four hearts, a single, hyperdense structure was detected within the right fibrous trigone of the cardiac skeleton. high resolution scans and histopatholog ...202032523027
forgetting in chimpanzees (pan troglodytes): what is the role of interference?humans are constantly acquiring new information and skills. however, forgetting is also a common phenomenon in our lives. understanding the lability of memories is critical to appreciate how they are formed as well as forgotten. here we investigate the lability of chimpanzees' short-term memories and assess what factors cause forgetting in our closest relatives. in two experiments, chimpanzees were presented with a target task, which involved remembering a reward location, followed by the presen ...202032470033
adolescent and young adult male chimpanzees form affiliative, yet aggressive, relationships with females.primates frequently form affiliative relationships that have important fitness consequences. affiliative relationships between unrelated males and females are ubiquitous in humans but are not widely reported in humans' closest living relatives, chimpanzees (pan troglodytes). instead, adult male chimpanzees are extremely aggressive to females, using the aggression to coerce females to mate with them. adolescent male chimpanzees are physically and socially immature and unable to use aggression tow ...202032464481
sexual dimorphism in chimpanzee (pan troglodytes schweinfurthii) and human age-specific fertility.across vertebrates, species with intense male mating competition and high levels of sexual dimorphism in body size generally exhibit dimorphism in age-specific fertility. compared with females, males show later ages at first reproduction and earlier reproductive senescence because they take longer to attain adult body size and musculature, and maintain peak condition for a limited time. this normally yields a shorter male duration of effective breeding, but this reduction might be attenuated in ...202032454364
the strategies used by chimpanzees (pan troglodytes) and children (homo sapiens) to solve a simple coordination problem.one of the challenges of collaboration is to coordinate decisions with others, and recent theories have proposed that humans, in particular, evolved skills to address this challenge. to test this hypothesis, we compared the coordination abilities of 4-year-old children and chimpanzees with a simple coordination problem. to retrieve a reward from a "puzzle box," pairs of individuals were simply required to choose the same 1 of 4 options. if successful, they each received the same reward, so there ...202032437179
evaluation of relationships between results of electrocardiography and echocardiography in 341 chimpanzees (pan troglodytes).to examine potential relationships between ecg characteristics and echocardiographic measures of cardiac structure in chimpanzees (pan troglodytes).202032436790
systematic mapping of developmental milestones in wild chimpanzees.postnatal development is protracted relative to lifespan in many primates, including modern humans (homo sapiens), facilitating the acquisition of key motor, communication and social skills that can maximize fitness later in life. nevertheless, it remains unclear what evolutionary drivers led to extended immature periods. while the developmental milestone literature is well established in humans, insight we can gain from one-species models is limited. by comparing the timing of relatable develop ...202032412141
post-event misinformation effects in a language-trained chimpanzee (pan troglodytes).errors of source monitoring are widespread human memory challenges, and our memories are subject to distortion upon the presentation of subsequent misinformation. less is known about if and when misinformation effects occur in nonhuman species' memory. here we tested a symbol-trained chimpanzee's recall memory of a hidden food item's identity after a 10-min delay. during this delay, the subject was sometimes (depending on the condition) shown consistent or inconsistent video information about th ...202032388782
ophthalmic findings in 10 captive, anesthetized chimpanzees (pan troglodytes).to document ophthalmic findings, schirmer's tear test i (stt), and intraocular pressure (iop) values for anesthetized chimpanzees (pan troglodytes).202032374078
targeted conservation genetics of the endangered chimpanzee.populations of the common chimpanzee (pan troglodytes) are in an impending risk of going extinct in the wild as a consequence of damaging anthropogenic impact on their natural habitat and illegal pet and bushmeat trade. conservation management programmes for the chimpanzee have been established outside their natural range (ex situ), and chimpanzees from these programmes could potentially be used to supplement future conservation initiatives in the wild (in situ). however, these programmes have o ...202032346130
monkeypox virus emergence in wild chimpanzees reveals distinct clinical outcomes and viral diversity.monkeypox is a viral zoonotic disease on the rise across endemic habitats. despite the growing importance of monkeypox virus, our knowledge on its host spectrum and sylvatic maintenance is limited. here, we describe the recent repeated emergence of monkeypox virus in a wild, human-habituated western chimpanzee (pan troglodytes verus, hereafter chimpanzee) population from taï national park, ivory coast. through daily monitoring, we show that further to causing its typical exanthematous syndrome, ...202032341480
identification of genes involved in the evolution of human intelligence through combination of inter-species and intra-species genetic variations.understanding the evolution of human intelligence is an important undertaking in the science of human genetics. a great deal of biological research has been conducted to search for genes which are related to the significant increase in human brain volume and cerebral cortex complexity during hominid evolution. however, genetic changes affecting intelligence in hominid evolution have remained elusive. we supposed that a subset of intelligence-related genes, which harbored intra-species variations ...202032337102
greater variability in chimpanzee (pan troglodytes) brain structure among males.across the animal kingdom, males tend to exhibit more behavioural and morphological variability than females, consistent with the 'greater male variability hypothesis'. this may reflect multiple mechanisms operating at different levels, including selective mechanisms that produce and maintain variation, extended male development, and x chromosome effects. interestingly, human neuroanatomy shows greater male variability, but this pattern has not been demonstrated in any other species. to address ...202032315585
innovation in chimpanzees.the study of innovation in non-human animals (henceforth: animals) has recently gained momentum across fields including primatology, animal behaviour and cultural evolution. examining the rate of innovations, and the cognitive mechanisms driving these innovations across species, can provide insights into the evolution of human culture. especially relevant to the study of human culture is one of our closest living relatives, the chimpanzee (pan troglodytes). both wild and captive chimpanzees demo ...202032307892
testing the individual and social learning abilities of task-naïve captive chimpanzees (pan troglodytes sp.) in a nut-cracking task.nut-cracking is often cited as one of the most complex behaviours observed in wild chimpanzees. however, the cognitive mechanisms behind its acquisition are still debated. the current null hypothesis is that the form of nut-cracking behaviour relies on variants of social learning, with some researchers arguing, more precisely, that copying variants of social learning mechanisms are necessary. however, to date, very few experiments have directly investigated the potentially sufficient role of ind ...202032195057
chimpanzee ranging responses to fruit availability in a high-elevation environment.most primates experience seasonal fluctuations in the availability of food resources and face the challenge of balancing energy expenditure with energy gain during periods of resource scarcity. this is likely to be particularly challenging in rugged, montane environments, where available energy is relatively low and travel costs are high. chimpanzees (pan troglodytes) show extensive behavioral diversity across study sites. yet, as most research has focused on low- and mid-elevation sites, little ...202032187721
quantitative shape analysis of the deltoid tuberosity of modern humans (homo sapiens) and common chimpanzees (pan troglodytes).to identify anatomical differences in the deltoid tuberosity of homo sapiens and pan troglodytes, potentially relating to the different uses of the forelimb in these two phylogenetically related species.202032173565
a chomped chimp: new evidence of tooth marks on an adult chimpanzee (pan troglodytes verus).to describe and interpret previously unreported marks on the dry cranium of an adult chimpanzee (pan troglodytes verus) from côte d'ivoire at the smithsonian's national museum of natural history (usnm 450071).202032170724
genetic diagnosis of trisomy 21 in chimpanzees (pan troglodytes).the most frequent chromosomal aneuploidy in humans, trisomy 21 (t21), has only been reported twice in the common chimpanzee (pan troglodytes). in both cases, phenotypical traits were comparable to human t21 traits and were formally diagnosed through conventional techniques like chromosomal staining. here, we present the first application of sequencing data as a diagnostic tool to compare chromosomal dosage imbalances in chimpanzees. by calculating the ratio of mapped reads on each chromosome bet ...202032162159
modeling of early neural development in vitro by direct neurosphere formation culture of chimpanzee induced pluripotent stem cells.evolutionary developmental biology of our closest living relative, the chimpanzee (pan troglodytes), is essential for understanding the origin of human traits. however, it is difficult to access developmental events in the chimpanzee in vivo because of technical and ethical restrictions. induced pluripotent stem cells (ipscs) offer an alternative in vitro model system to investigate developmental events by overcoming the limitations of in vivo study. here, we generated chimpanzee ipscs from adul ...202032151953
identification of structural variation in chimpanzees using optical mapping and nanopore sequencing.recent efforts to comprehensively characterize great ape genetic diversity using short-read sequencing and single-nucleotide variants have led to important discoveries related to selection within species, demographic history, and lineage-specific traits. structural variants (svs), including deletions and inversions, comprise a larger proportion of genetic differences between and within species, making them an important yet understudied source of trait divergence. here, we used a combination of l ...202032143403
chimpanzee coordination and potential communication in a two-touchscreen turn-taking game.recent years have seen a growing interest in the question of whether and how groups of nonhuman primates coordinate their behaviors for mutual benefit. on the one hand, it has been shown that chimpanzees in the wild and in captivity can solve various coordination problems. on the other hand, evidence of communication in the context of coordination problems is scarce. here, we investigated how pairs of chimpanzees (pan troglodytes) solved a problem of dynamically coordinating their actions for ac ...202032098996
my life among the apes.i have spent over 40 years studying the behavior of our closest living relatives, the apes. in this paper, i review my research on the spacing, mating, and vocal behavior of gibbons and orangutans (pongo pygmaeus) and the vocal and social behavior of chimpanzees (pan troglodytes). i devote special attention to results derived from a 25-year-long study of a remarkable and extraordinarily large group of chimpanzees that has recently fissioned at ngogo in kibale national park, uganda. i conclude wi ...202032096269
longitudinal changes in the targets of chimpanzee (pan troglodytes) hunts at mahale mountains national park: how and why did they begin to intensively hunt red colobus (piliocolobus rufomitratus) in the 1980s?the hunting activities of chimpanzees (pan troglodytes) at mahale mountains national park exhibited a significant change over a 46-year observation period, shifting from sporadic hunting for small ungulates and primates through seizure or chasing, to a specialized hunting habit for red colobus (piliocolobus rufomitratus). by the early 1980s, a new hunting habit had developed through the following stages: (1) occasional single kills by mature/adolescent males, (2) multiple kills by mature/adolesc ...202032095911
wood and meat as complementary sources of sodium for kanyawara chimpanzees (pan troglodytes).sodium, a vital micronutrient that is often in scarce supply for tropical herbivores, is sometimes found at high concentration in decaying wood. we tested two hypotheses for chimpanzees: first, that wood-eating facilitates acquisition of sodium; second, that wood-eating occurs in response to the low availability of sodium from other dietary sources.202032091137
the implementation and initial evaluation of a physical therapy program for captive chimpanzees (pan troglodytes).due to advances in captive nonhuman primate (nhp) medical care, the number of geriatric chimpanzees (≥35-years old) is growing. with old age comes a variety of physical conditions, including arthritis, stroke, and mobility impairments. programs aimed at enhancing the welfare of geriatric chimpanzees are now quite common, but there are few published empirical evaluations of the efficacy of such programs. the current study aimed to create, implement, and evaluate the effects of participation in a ...202032077522
the macronutrient composition of wild and cultivated plant foods of west african chimpanzees (pan troglodytes verus) inhabiting an anthropogenic landscape.agricultural expansion encroaches on tropical forests and primates in such landscapes frequently incorporate crops into their diet. understanding the nutritional drivers behind crop-foraging can help inform conservation efforts to improve human-primate coexistence. this study builds on existing knowledge of primate diets in anthropogenic landscapes by estimating the macronutrient content of 24 wild and 11 cultivated foods (90.5% of food intake) consumed by chimpanzees (pan troglodytes verus) at ...202032003053
social rank overrides environmental and community fluctuations in determining meat access by female chimpanzees in the taï national park, côte d'ivoire.meat, long hypothesized as an important food source in human evolution, is still a substantial component of the modern human diet, with some humans relying entirely on meat during certain times of the year. understanding the socio-ecological context leading to the successful acquisition and consumption of meat by chimpanzees (pan troglodytes), our closest living relative, can provide insight into the emergence of this trait because humans and chimpanzees are unusual among primates in that they b ...202032002324
placenta accreta in an oragnutan (pongo abelii) and a chimpanzee (pan troglodytes).placenta accreta is defined as abnormal adherence of the placenta to the uterine wall. placenta accreta is recognized as a common problem in human medicine, but has apparently not been reported previously in great apes, despite similarity in their reproductive biology. a 36-year-old multiparous female sumatran orangutan (pongo abelii) and a 20-year-old nulliparous female chimpanzee (pan troglodytes), with gross uterine and histological uterine vascular changes that are characteristic of placenta ...202031955798
color discrimination and color preferences in chimpanzees (pan troglodytes).chimpanzees (pan troglodytes) have been known for a long time to have color vision identical to humans (grether in j comp psychol 29(2):167-177, 1940b; jacobs et al. in vis res 36(16):2587-2594, 1996). with this study, we wonder if chimpanzees, as humans, show preferences for some colors rather than others. during a first range of experiments, we test their ability to discriminate all the colors from our set, through easy matching-to-sample tasks. the seven chimpanzees that participate in this f ...202031950319
forest fragments become farmland: dietary response of wild chimpanzees (pan troglodytes) to fast-changing anthropogenic landscapes.behavioral flexibility, including an ability to modify feeding behavior, is a key trait enabling primates to survive in forest fragments. in human-dominated landscapes, unprotected forest fragments can become progressively degraded, and may be cleared entirely, challenging the capacity of primates to adjust to the changes. we examined responses of wild chimpanzees (pan troglodytes schweinfurthii) to major habitat change: that is, clearance of forest fragments for agriculture. over 7 years, fragm ...202031944360
early life experience and alterations of group composition shape the social grooming networks of former pet and entertainment chimpanzees (pan troglodytes).the long-term effects of early life adversities on social capacities have been documented in humans and wild-caught former laboratory chimpanzees (pan troglodytes). however, former pet and entertainment chimpanzees have received little attention to date. this study aimed to investigate the long-term effects of early life experience on 18 former pet and entertainment chimpanzees, based on social grooming data collected at a primate rescue centre over a 12-year period. moreover, we also focused on ...202031940322
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