| aging and sex affect soluble alpha klotho levels in bonobos and chimpanzees. | throughout life, physiological homeostasis is challenged and the capacity to cope with such challenges declines with increasing age. in many species, sex differences exist in life expectancy. sex-specific differences have been related to extrinsic factors like mate competition and/or intrinsic proximate mechanisms such as hormonal changes. in humans, an intrinsic factor related to aging is soluble alpha klotho (α-kl). both sexes show an age-related decline in α-kl, but throughout life women have ... | 2018 | 30250491 |
| insights into the musculature of the bonobo hand. | the human hand is well known for its unique dexterity which is largely facilitated by a highly mobile, long and powerful thumb that enables both tool manufacturing and use, a key component of human evolution. the bonobo (pan paniscus), the closest extant relative to modern humans together with the chimpanzee (pan troglodytes), also possesses good manipulative capabilities but with a lower level of dexterity compared with modern humans. despite the close phylogenetic relationship between bonobos ... | 2018 | 29938781 |
| the goal of ape pointing. | captive great apes regularly use pointing gestures in their interactions with humans. however, the precise function of this gesture is unknown. one possibility is that apes use pointing primarily to direct attention (as in "please look at that"); another is that they point mainly as an action request (such as "can you give that to me?"). we investigated these two possibilities here by examining how the looking behavior of recipients affects pointing in chimpanzees (pan troglodytes) and bonobos ( ... | 2018 | 29694358 |
| inter- and intraspecific variations in the pectoral muscles of common chimpanzees (pan troglodytes), bonobos (pan paniscus), and humans (homo sapiens). | we have analyzed anatomic variations in the pectoralis major and pectoralis minor muscles of common chimpanzees (pan troglodytes) and bonobos (pan paniscus) and compared them to anatomic variations in these muscles in humans (homo sapiens). we have macroscopically dissected these muscles in six adult pan troglodytes, five pan paniscus of ages ranging from fetus to adult, and five adult homo sapiens. although pan troglodytes are thought to lack a separate pectoralis abdominis muscle, we have iden ... | 2018 | 29581990 |
| dentoalveolar abscess variation among three groups of chimpanzees (pan troglodytes schweinfurthii, pan troglodytes troglodytes, and pan paniscus). | the prevalence and pattern of periodontal and periapical dental abscess lesions are examined in 399 wild caught chimpanzee mandibles and maxillae from museum contexts (138 pan troglodytes troglodytes, 152 pan troglodytes schweinfurthii and 109 pan paniscus). this study tests two predictions. first, canine size is the key determining factor in dental abscesses. second, tooth breakage leads to higher frequencies of abscesses. abscess frequencies were calculated for adult males (p. t. troglodytes 1 ... | 2012 | 29539346 |
| a quantitative comparison of terrestrial herbaceous food consumption by pan paniscus in the lomako forest, zaire, and pan troglodytes in the kibale forest, uganda. | differences in the social organization and dental morphology of pan paniscus (bonobos) and pan troglodytes (chimpanzees) have been related to differences in the spatiotemporal availability of food and its exploitation. the presence of abundant terrestrial herbaceous vegetation (thv) in the bonobo's habitat and the apparent greater reliance on herbs for food has been used to explain differences in party size and, by extension, social organization. using fecal analysis, we assess quantitatively th ... | 1994 | 31936906 |
| composition of the diet of chimpanzees and comparisons with that of sympatric lowland gorillas in the lopé reserve, gabon. | over an eight-year period, a total of 174 food items were recorded for chimpanzees (pan t. troglodytes) in the lopé reserve in central gabon. plant foods, principally fruit, dominated the diet but insects were eaten regularly, and predation on at least three species of mammal occurred infrequently. the diversity of the vegetative component of the diet (leaves, stems, and bark) was probably underestimated by fecal analysis. comparison of chimpanzee diet at lopé with that of sympatric lowland gori ... | 1993 | 31937009 |
| distribution of terrestrial herbaceous vegetation and its consumption by pan paniscus in the lomako forest, zaire. | data available on behavior and morphology of pan paniscus (bonobos) suggest that terrestrial herbaceous vegetation (thv) is an important component of their diet and that it may be preferred by bonobos to a greater extent than by chimpanzees (pan troglodytes). it has also been reported that thv is ubiquitously distributed in the lowland rain forests inhabited by bonobos. these data suggest that thv exploitation may be causally related to the evolution of the more cohesive social system found in b ... | 1991 | 31952402 |
| da/dapi fluorescent bands in the chromosomes of pan paniscus. | the fluorochrome pattern produced by da/dapi double staining in pan paniscus chromosomes is reported. the location of da/dapi prominent bands differs from that reported for all other hominoid species. however, the pattern in the pygmy chimpanzee is most similar to that seen in pan troglodytes. comparison of the da/dapi pattern of the other hominoid species allows the construction of a proposed hominoid ancestral karyotype and a preliminary phylogenetic reconstruction of da/dapi bands for the gre ... | 1988 | 32093428 |
| 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 ... | 2020 | 33169878 |
| 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 ... | 2020 | 33169860 |
| 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 ... | 2020 | 33118192 |
| 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 ... | 2020 | 33094407 |
| 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 ... | 2020 | 33034790 |
| 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, ... | 2020 | 33016499 |
| 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 ... | 2020 | 33007243 |
| 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 ... | 2020 | 32995086 |
| 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, ... | 2020 | 32985084 |
| 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 ... | 2020 | 32978976 |
| 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 ... | 2020 | 32974394 |
| 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 ... | 2020 | 32973465 |
| 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 ... | 2020 | 32955646 |
| 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 ... | 2020 | 32951551 |
| 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 ... | 2020 | 32951547 |
| 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 ... | 2020 | 32951545 |
| 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 ... | 2020 | 32951544 |
| 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 ... | 2020 | 32934202 |
| 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 ... | 2020 | 32933484 |
| 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 ... | 2020 | 32907979 |
| 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 ... | 2020 | 32900313 |
| 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 ... | 2020 | 32874782 |
| 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. | 2020 | 32865237 |
| 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. | 2020 | 32864759 |
| influence of fruit availability on macronutrient and energy intake by female chimpanzees. | daily energy intake of adult female mammals is influenced by environmental conditions and physiological requirements, including reproduction. we examined the effects of fruit availability on macronutrient and metabolisable energy intake by adult female chimpanzees (pan troglodytes schweinfurthii) of the kanyawara community in kibale national park, uganda from january 2014 through june 2015. drupe fruits were abundant for four months, whereas the other fourteen months were dominated by fig fruits ... | 2019 | 32863473 |
| 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 ... | 2020 | 32860627 |
| 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 ... | 2020 | 32856319 |
| 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. | 2020 | 32779224 |
| 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. | 2020 | 32767577 |
| 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 ... | 2020 | 32683168 |
| 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 ... | 2020 | 32663207 |
| 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 ... | 2020 | 32652259 |
| 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 ... | 2020 | 32617082 |
| 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 ... | 2020 | 32605080 |
| 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 ... | 2020 | 32599590 |
| 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 ... | 2020 | 32596775 |
| 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. | 2020 | 32584460 |
| 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 ... | 2020 | 32575533 |
| 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 ... | 2020 | 32566394 |
| 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 ... | 2020 | 32561234 |
| 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. | 2020 | 32542742 |
| 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 ... | 2020 | 32529982 |
| 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 ... | 2020 | 32523027 |
| 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 ... | 2020 | 32470033 |
| 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 ... | 2020 | 32464481 |
| 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 ... | 2020 | 32454364 |
| 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 ... | 2020 | 32437179 |
| 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). | 2020 | 32436790 |
| 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 ... | 2020 | 32412141 |
| 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 ... | 2020 | 32388782 |
| 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). | 2020 | 32374078 |
| 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 ... | 2020 | 32346130 |
| 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, ... | 2020 | 32341480 |
| 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 ... | 2020 | 32337102 |
| 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 ... | 2020 | 32315585 |
| 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 ... | 2020 | 32307892 |
| 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 ... | 2020 | 32195057 |
| 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 ... | 2020 | 32187721 |
| 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. | 2020 | 32173565 |
| 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). | 2020 | 32170724 |
| 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 ... | 2020 | 32162159 |
| 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 ... | 2020 | 32151953 |
| 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 ... | 2020 | 32143403 |
| 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 ... | 2020 | 32098996 |
| 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 ... | 2020 | 32096269 |
| 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 ... | 2020 | 32095911 |
| 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. | 2020 | 32091137 |
| 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 ... | 2020 | 32077522 |
| 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 ... | 2020 | 32003053 |
| 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 ... | 2020 | 32002324 |
| 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 ... | 2020 | 31955798 |
| 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 ... | 2020 | 31950319 |
| 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 ... | 2020 | 31944360 |
| 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 ... | 2020 | 31940322 |
| the use of citalopram hydrobromide to manage aggression in a male chimpanzee (pan troglodytes). | at times severe, and occasionally fatal, aggression plays an intrinsic role in chimpanzee behavior and social dynamics, particularly among male chimpanzees in both managed and free-ranging troops. at the los angeles zoo, one adult male's natural aggressive behavior developed into unmanageable violence during a period of social and emotional instability consequent to the lack of an established alpha male in the colony. the severity and duration of resulting attacks on a subdominant member of the ... | 2020 | 31926537 |
| body perception in chimpanzees (pan troglodytes): the effect of body structure changes. | chimpanzees have been found to show the inversion effect to visual stimuli of intact chimpanzee bodies, suggesting that they have a specific way of body processing. in this study, we examined how changes of body structures affect the inversion effect to reveal the properties of their body processing. we focused on two aspects of body structures: the first-order relations (i.e., body part arrangements) and body proportions. the experimental conditions had stimuli of chimpanzee bodies with scrambl ... | 2020 | 31916785 |
| maternal effects on offspring growth indicate post-weaning juvenile dependence in chimpanzees (pan troglodytes verus). | in animals with altricial offspring, most growth occurs after birth and may be optimized by post-natal maternal care. maternal effects on growth may be influenced by individual characteristics of the mothers, such as social status, individual investment strategies and the length of association with offspring. the prolonged juvenile dependence seen in humans is a distinctive life history adaptation, which may have evolved to facilitate sustained somatic and brain growth.in chimpanzees, offspring ... | 2020 | 31911809 |
| adolescent male chimpanzees (pan troglodytes) form social bonds with their brothers and others during the transition to adulthood. | social relationships play an important role in animal behavior. bonds with kin provide indirect fitness benefits, and those with nonkin may furnish direct benefits. adult male chimpanzees (pan troglodytes) exhibit social bonds with maternal brothers as well as unrelated adult males, facilitating cooperative behavior, but it is unclear when these bonds develop. prior studies suggest that social bonds emerge during adolescence. alternatively, bonds may develop during adulthood when male chimpanzee ... | 2020 | 31903634 |
| between-group competition impacts reproductive success in wild chimpanzees. | between-group competition in social animals appears to be a prominent selective pressure shaping the evolution of territoriality and cooperation [1-4]. evidence for an effect of between-group competition on fitness in territorial species, however, is mostly lacking because of difficulty in measuring between-group competition and its long-term impact [5]. between-group competition corresponds to a complex set of interactions between neighboring groups, and its intensity seems to depend on the com ... | 2020 | 31902731 |
| chimpanzees (pan troglodytes) tolerate some degree of inequity while cooperating but refuse to donate effort for nothing. | in cooperative hunting, a carcass cannot be divided equally, and hunts may be unsuccessful. we studied how chimpanzees respond to these two variables, working for unequal rewards and no rewards, which have been rarely included in experimental cooperative tasks. we presented chimpanzees with a task requiring three chimpanzees to work together and varied the reward structure in two separate experiments. in experiment 1, two individuals received more rewards than the third, making the outcome unequ ... | 2020 | 31894611 |
| how to measure chimpanzee party size? a methodological comparison. | chimpanzees (pan troglodytes) live in fission-fusion societies where community members form temporary parties that frequently change in size and composition. chimpanzee party size and composition have been widely studied to identify proximate causes of grouping patterns, and party size estimates are used to assess population sizes and densities. numerous socio-ecological factors influence chimpanzee party size, but findings differ across studies. various methods to measure party size exist, incl ... | 2020 | 31894437 |
| rhythmic swaying induced by sound in chimpanzees (pan troglodytes). | music and dance are universal across human culture and have an ancient history. one characteristic of music is its strong influence on movement. for example, an auditory beat induces rhythmic movement with positive emotions in humans from early developmental stages. in this study, we investigated if sound induced spontaneous rhythmic movement in chimpanzees. three experiments showed that: 1) an auditory beat induced rhythmic swaying and other rhythmic movements, with larger responses from male c ... | 2020 | 31871195 |
| chimpanzees use tree species with a resonant timbre for accumulative stone throwing. | animals use tools for communication relatively rarely compared to tool use for extractive foraging. we investigated the tool-use behaviour accumulative stone throwing (ast) in wild chimpanzees, who regularly throw rocks at trees, producing impact sounds and resulting in the aggregations of rocks. the function of ast remains unknown but appears to be communication-related. we conducted field experiments to test whether impact sounds produced by throwing rocks at trees varied according to the tree ... | 2019 | 31847748 |
| 3d shape analyses of extant primate and fossil hominin vertebrae support the ancestral shape hypothesis for intervertebral disc herniation. | recently we proposed an evolutionary explanation for a spinal pathology that afflicts many people, intervertebral disc herniation (plomp et al. [2015] bmc evolutionary biology 15, 68). using 2d data, we found that the bodies and pedicles of lower vertebrae of pathological humans were more similar in shape to those of chimpanzees than were those of healthy humans. based on this, we hypothesized that some individuals are more prone to intervertebral disc herniation because their vertebrae exhibit ... | 2019 | 31842740 |
| differences in mhc-b diversity and kir epitopes in two populations of wild chimpanzees. | the major histocompatibility complex (mhc) class i genes play a critical role within the immune system, both by the presentation of antigens from intracellular pathogens to immunocompetent cells and by the interaction with killer cell immunoglobulin-like receptors (kir) on natural killer cells (nk cells). genes of the mhc are highly diverse, and mhc variation can have effects on the immune functionality of individuals; hence, comparisons of mhc diversity among closely related phylogenetic taxa m ... | 2019 | 31797008 |
| social and ecological complexity is associated with gestural repertoire size of wild chimpanzees. | increasing our understanding of primate gestural communication can provide new insights into language evolution. a key question in primate communication is the association between the social relationships of primates and their repertoire of gestures. such analyses can reveal how primates use their repertoire of gestural communication to maintain their networks of family and friends, much as humans use language to maintain their social networks. in this study we examined the association between t ... | 2020 | 31773892 |
| oral microbiome diversity in chimpanzees from gombe national park. | historic calcified dental plaque (dental calculus) can provide a unique perspective into the health status of past human populations but currently no studies have focused on the oral microbial ecosystem of other primates, including our closest relatives, within the hominids. here we use ancient dna extraction methods, shotgun library preparation, and next generation illumina sequencing to examine oral microbiota from 19 dental calculus samples recovered from wild chimpanzees (pan troglodytes sch ... | 2019 | 31758037 |
| cross-species validation of human specific str system, sureid® 21g and sureid® 23comp (health gene technologies) in chimpanzee (pan troglodytes). | the human specific commercially available strs system are often not tested in non human primates for their cross applicability. the aim of this study is to test cross-species validation of two commercially available human specific str kits i.e. sureid® 21g and sureid® 23comp (health gene technologies) for their positive application in chimpanzee (pan troglodytes). | 2019 | 31744541 |
| human-like adrenal development in wild chimpanzees: a longitudinal study of urinary dehydroepiandrosterone-sulfate and cortisol. | the development of the adrenal cortex varies considerably across primates, being most conspicuous in humans, where a functional zona reticularis-the site of dehydroepiandrosterone-sulfate (dhea/s) production-does not develop until middle childhood (5-8 years). prior reports suggest that a human-like adrenarche, associated with a sharp prepubertal increase in dhea/s, may only occur in the genus pan. however, the timing and variability in adrenarche in chimpanzees remain poorly described, owing to ... | 2020 | 31709585 |
| a modern approach to minimally invasive surgery and laparoscopic sterilization in a chimpanzee. | we present the case of ruby, a 21-year-old hand-reared chimpanzee (pan troglodytes) who had an obstetric history significant for a premature stillborn infant that was conceived while on oral contraceptive pills, followed by a full term healthy delivery complicated by neonatal demise attributed to inappropriate maternal care. she was recommended for permanent sterilization due to her history of conception while on oral contraceptives. she underwent uncomplicated laparoscopic bilateral tubal ligat ... | 2019 | 31662944 |
| assessment of in situ nest decay rate for chimpanzees (pan troglodytes ellioti matschie, 1914) in mbam-djerem national park, cameroon: implications for long-term monitoring. | accurate assessment of great ape populations is a prerequisite for conservation planning. indirect survey methods using nest and dung, and a set of conversion parameters related to nest decay rates, are increasingly used. most surveys use the standing crop nest count (scnc) method, whereby nests are counted along transects and the estimated nest density is converted into chimpanzee density using an often non-local nest decay rate. the use of non-local decay rate is thought to introduce substanti ... | 2020 | 31659555 |