Publications

the 'other faunivory' revisited: insectivory in human and non-human primates and the evolution of human diet.	the role of invertebrates in the evolution of human diet has been under-studied by comparison with vertebrates and plants. this persists despite substantial knowledge of the importance of the 'other faunivory', especially insect-eating, in the daily lives of non-human primates and traditional human societies, especially hunters and gatherers. most primates concentrate on two phyla, mollusca and arthropoda, but of the latter's classes, insects (especially five orders: coleoptera, hymenoptera, iso ...	2014	24560030
curtailing chimpanzee exploitation.		2014	24558144
array-based assay detects genome-wide 5-mc and 5-hmc in the brains of humans, non-human primates, and mice.	methylation on the fifth position of cytosine (5-mc) is an essential epigenetic mark that is linked to both normal neurodevelopment and neurological diseases. the recent identification of another modified form of cytosine, 5-hydroxymethylcytosine (5-hmc), in both stem cells and post-mitotic neurons, raises new questions as to the role of this base in mediating epigenetic effects. genomic studies of these marks using model systems are limited, particularly with array-based tools, because the stan ...	2014	24524199
poor receptive joint attention skills are associated with atypical gray matter asymmetry in the posterior superior temporal gyrus of chimpanzees (pan troglodytes).	clinical and experimental data have implicated the posterior superior temporal gyrus as an important cortical region in the processing of socially relevant stimuli such as gaze following, eye direction, and head orientation. gaze following and responding to different socio-communicative signals is an important and highly adaptive skill in primates, including humans. here, we examined whether individual differences in responding to socio-communicative cues was associated with variation in either ...	2014	24523703
gambling primates: reactions to a modified iowa gambling task in humans, chimpanzees and capuchin monkeys.	humans will, at times, act against their own economic self-interest, for example, in gambling situations. to explore the evolutionary roots of this behavior, we modified a traditional human gambling task, the iowa gambling task (igt), for use with chimpanzees, capuchin monkeys and humans. we expanded the traditional task to include two additional payoff structures to fully elucidate the ways in which these primate species respond to differing reward distributions versus overall quantities of rew ...	2014	24504555
comparative primate neuroimaging: insights into human brain evolution.	comparative neuroimaging can identify unique features of the human brain and teach us about human brain evolution. comparisons with chimpanzees, our closest living primate relative, are critical in this endeavor. structural magnetic resonance imaging (mri) has been used to compare brain size development, brain structure proportions and brain aging. positron emission tomography (pet) imaging has been used to compare resting brain glucose metabolism. functional mri (fmri) has been used to compare ...	2014	24501779
socially learned habituation to human observers in wild chimpanzees.	habituation to human observers is an essential tool in animal behaviour research. habituation occurs when repeated and inconsequential exposure to a human observer gradually reduces an animal's natural aversive response. despite the importance of habituation, little is known about the psychological mechanisms facilitating it in wild animals. although animal learning theory offers some account, the patterns are more complex in natural than in laboratory settings, especially in large social groups ...	2014	24500498
triadic social interactions operate across time: a field experiment with wild chimpanzees.	social animals cooperate with bonding partners to outcompete others. predicting a competitor's supporter is likely to be beneficial, regardless of whether the supporting relationship is stable or transient, or whether the support happens immediately or later. although humans make such predictions frequently, it is unclear to what extent animals have the cognitive abilities to recognize others' transient bond partners and to predict others' coalitions that extend beyond the immediate present. we ...	2014	24500174
can a chimp say "no"? reenvisioning chimpanzee dissent in harmful research.	among the "hard cases" of captive animal research is the continued use of chimpanzees in harmful experimental science. in a recent article i contend that contemporary animal welfare science and chimpanzee behavioral studies permit, if not require, a reappraisal of the moral significance of chimpanzee dissent from participation in certain experiments. in what follows, i outline my earlier argument, provide a brief survey of some central concepts in pediatric research ethics, and use these to enri ...	2014	24495658
boy will be boys: sex differences in wild infant chimpanzee social interactions.	sex differences in the behaviour of human children are a hotly debated and often controversial topic. however, several recent studies have documented a biological basis to key aspects of child social behaviour. to further explore the evolutionary basis of such differences, we investigated sex differences in sociability in wild chimpanzee, pan troglodytes schweinfurthii, infants at gombe national park, tanzania. we used a long-term data set on mother-infant behaviour to analyse the diversity of i ...	2014	24489384
preclinical drug metabolism and pharmacokinetics, and prediction of human pharmacokinetics and efficacious dose of the investigational aurora a kinase inhibitor alisertib (mln8237).	alisertib (mln8237) is an investigational potent aurora a kinase inhibitor currently under clinical trials for hematological and nonhematological malignancies. nonclinical investigation showed that alisertib is a highly permeable compound with high plasma protein binding, low plasma clearance, and moderate volume of distribution in rats, dogs, monkeys and chimpanzees. consistent with the above properties, the oral bioavailability in animals was greater than 82%. the predicted human oral pharmaco ...	2014	24484538
tradition over trend: neighboring chimpanzee communities maintain differences in cultural behavior despite frequent immigration of adult females.	the notion of animal culture has been well established mainly through research aiming at uncovering differences between populations. in chimpanzees (pan troglodytes verus), cultural diversity has even been found in neighboring communities, where differences were observed despite frequent immigration of individuals. female chimpanzees transfer at the onset of sexual maturity at an age, when the behavioral repertoire is fully formed. with immigrating females, behavioral variety enters the group. l ...	2014	24482055
chimpanzees form long-term memories for food locations after limited exposure.	remembering the location of fruiting trees for extended periods of time has been hypothesized to play a major role in the evolution of primate cognition. such ability would be especially useful when paired with a fast learning mechanism capable of consolidating long-term memory after minimal exposure. we investigated whether chimpanzees (pan troglodytes) can remember different food locations after minimal exposure (i.e., 1-2 trials) both after 24 hr and after 3-month. we released pairs of chimpa ...	2014	24482025
macroscopic inspection of ape feces: what's in a quantification method?	macroscopic inspection of feces has been used to investigate primate diet. the limitations of this method to identify food-items to species level have long been recognized, but ascertaining aspects of diet (e.g., folivory) are achievable by quantifying food-items in feces. quantification methods applied include rating food-items using a scale of abundance, estimating their percentage volume, and weighing food-items. however, verification as to whether or not composition data differ, depending on ...	2014	24482001
genetic influences on receptive joint attention in chimpanzees (pan troglodytes).	despite their genetic similarity to humans, our understanding of the role of genes on cognitive traits in chimpanzees remains virtually unexplored. here, we examined the relationship between genetic variation in the arginine vasopressin v1a receptor gene (avpr1a) and social cognition in chimpanzees. studies have shown that chimpanzees are polymorphic for a deletion in a sequence in the 5' flanking region of the avpr1a, dupb, which contains the variable rs3 repetitive element, which has been asso ...	2014	24440967
bidirectional promoters are the major source of gene activation-associated non-coding rnas in mammals.	the majority of non-coding rnas (ncrnas) involved in mrna metabolism in mammals have been believed to downregulate the corresponding mrna expression level in a pre- or post-transcriptional manner by forming short or long ncrna-mrna duplex structures. information on non-duplex-forming long ncrnas is now also rapidly accumulating. to examine the directional properties of transcription at the whole-genome level, we performed directional rna-seq analysis of mouse and chimpanzee tissue samples.	2014	24438357
competing for space: female chimpanzees are more aggressive inside than outside their core areas.	female space use can have important fitness consequences, which are likely due to differential access to food resources. many studies have explored spatial competition in solitary species, but little is known about how individuals in social species compete over shared space. in this study, we investigate spatial patterns of aggression among female east african chimpanzees, pan troglodytes schweinfurthii. this species provides an excellent opportunity to study spatial competition since (1) female ...	2014	24436495
genetic analyses suggest no immigration of adult females and their offspring into the sonso community of chimpanzees in the budongo forest reserve, uganda.	chimpanzees are frequently used to illustrate the relationship between sex differences in dispersal and sex differences in cooperation in primates and other group-living mammals. male chimpanzees are highly philopatric, typically remaining in their natal communities for their entire lives to cooperate with related males in competition against less related males from other groups, whereas females typically disperse once at adolescence and cooperate with each other less frequently. however, there ...	2014	24436205
how dolphins see the world: a comparison with chimpanzees and humans.	bottlenose dolphins use auditory (or echoic) information to recognise their environments, and many studies have described their echolocation perception abilities. however, relatively few systematic studies have examined their visual perception. we tested dolphins on a visual-matching task using two-dimensional geometric forms including various features. based on error patterns, we used multidimensional scaling to analyse perceptual similarities among stimuli. in addition to dolphins, we conducte ...	2014	24435017
widespread differences in cortex dna methylation of the "language gene" cntnap2 between humans and chimpanzees.	cntnap2, one of the largest genes in the human genome, has been linked to human-specific language abilities and neurodevelopmental disorders. our hypothesis is that epigenetic rather than genetic changes have accelerated the evolution of the human brain. to compare the cortex dna methylation patterns of human and chimpanzee cntnap2 at ultra-high resolution, we combined methylated dna immunoprecipitation (medip) with nimblegen tiling arrays for the orthologous gene and flanking sequences. approxi ...	2014	24434791
one of us? novel strategy aims at getting chimpanzees recognized as legal persons.		2014	24432955
food sharing is linked to urinary oxytocin levels and bonding in related and unrelated wild chimpanzees.	humans excel in cooperative exchanges between unrelated individuals. although this trait is fundamental to the success of our species, its evolution and mechanisms are poorly understood. other social mammals also build long-term cooperative relationships between non-kin, and recent evidence shows that oxytocin, a hormone involved in parent-offspring bonding, is likely to facilitate non-kin as well as kin bonds. in a population of wild chimpanzees, we measured urinary oxytocin levels following a ...	2014	24430853
chimpanzees modify intentional gestures to coordinate a search for hidden food.	humans routinely communicate to coordinate their activities, persisting and elaborating signals to pursue goals that cannot be accomplished individually. communicative persistence is associated with complex cognitive skills such as intentionality, because interactants modify their communication in response to another's understanding of their meaning. here we show that two language-trained chimpanzees effectively use intentional gestures to coordinate with an experimentally naive human to retriev ...	2014	24430433
histological features of layers and sublayers in cortical visual areas v1 and v2 of chimpanzees, macaque monkeys, and humans.	the layers and sublayers of primary visual cortex, or v1, in primates are easily distinguishable compared to those in other cortical areas, and are especially distinct in anthropoid primates - monkeys, apes, and humans - where they also vary in histological appearance. this variation in primate-specific specialization has led to a longstanding confusion over the identity of layer 4 and its proposed sublayers in v1. as the application of different histological markers relate to the issue of defin ...	2014	25788835
chimpanzees prefer african and indian music over silence.	[correction notice: an erratum for this article was reported in vol 40(4) of journal of experimental psychology: animal learning and cognition (see record 2014-35305-001). for the article, the below files were used to create the audio used in this study. the original west african akan and north indian raga pieces were used in their entirety and the japanese taiko piece was used from the 0:19 second mark through the end. the tempo of each piece was adjusted so that they maintained an identical ba ...	2014	25546107
why vocal production of atypical sounds in apes and its cerebral correlates have a lot to say about the origin of language.	ackermann et al. mention the "acquisition of species-atypical sounds" in apes without any discussion. in our commentary, we demonstrate that these atypical sounds in chimpanzees not only include laryngeal sounds, but also have a major significance regarding the origins of language, if we consider looking at their context of use, their social properties, their relations with gestures, their lateralization, and their neurofunctional correlates as well.	2014	25514955
suffodit inguina.	when julius caesar was stabbed, 23 times, on the ides of march, at least one of the daggers is supposed to have gone into his groin. he wasn't the last roman to have his privates attacked. and he wasn't the last primate. in competition for sexual access, gonads are occasionally targeted: canine incisions in monkey and ape scrota are not uncommon; and rumors had a number of roman emperors--from caligula and nero, to galba, vitellius, domitian, commodus, caracalla, elagabalus, to balbinus, pupienu ...	2014	25514523
effective population size does not predict codon usage bias in mammals.	synonymous codons are not used at equal frequency throughout the genome, a phenomenon termed codon usage bias (cub). it is often assumed that interspecific variation in the intensity of cub is related to species differences in effective population sizes (n e), with selection on cub operating less efficiently in species with small n e. here, we specifically ask whether variation in n e predicts differences in cub in mammals and report two main findings. first, across 41 mammalian genomes, cub was ...	2014	25505518
when maths trumps logic: probabilistic judgements in chimpanzees.	when searching for hidden food, do chimpanzees take into account both the number of hidden items and the number of potential hiding locations? we presented chimpanzees with two trays, each of them containing a different food/cup ratio and therefore a different likelihood of finding a baited cup among empty alternatives. subjects' performance was directly influenced by the relative difference (probability ratio (pr)) between the two given probabilities. interestingly, however, they did not apprec ...	2014	25505056
katie e. slocombe: award for distinguished scientific early career contributions to psychology.	apa's awards for distinguished scientific early career contributions to psychology recognize excellent young psychologists who have not held a doctoral degree for more than nine years. one of the 2014 award winners is katie e. slocombe, for "outstanding contributions to understanding the communication and cognition of our closest living animal relatives, the chimpanzees." slocombe's award citation, biography, and a selected bibliography are presented here.	2014	25486147
first description of the complete human xylosyltransferase-i promoter region.	human xylosyltransferase-i (xt-i) catalyzes the rate-limiting step in proteoglycan glycosylation. an increase in xylt1 mrna expression and serum xt activity is associated with diseases characterized by abnormal extracellular matrix accumulation like, for instance, fibrosis. nevertheless, physiological and pathological mechanisms of transcriptional xt regulation remain elusive.	2014	25480529
insights into the possible role of ifng and ifngr1 in kala-azar and post kala-azar dermal leishmaniasis in sudanese patients.	little is known about the parasite/host factors that lead to post kala-azar dermal leishmaniasis (pkdl) in some visceral leishmaniasis (vl) patients after drug-cure. studies in sudan provide evidence for association between polymorphisms in the gene (ifngr1) encoding the alpha chain of interferon-γ receptor type i and risk of pkdl. this study aimed to identify putative functional polymorphisms in the ifngr1 gene, and to determine whether differences in expression of interferon-γ (ifng) and ifngr ...	2014	25466928
sexual conflict: nice guys finish last.	male chimpanzees are often aggressive towards females. a new study from gombe national park in tanzania reports that persistent attacks increase a male's probability of siring offspring.	2014	25465331
sexually coercive male chimpanzees sire more offspring.	in sexually reproducing animals, male and female reproductive strategies often conflict. in some species, males use aggression to overcome female choice, but debate persists over the extent to which this strategy is successful. previous studies of male aggression toward females among wild chimpanzees have yielded contradictory results about the relationship between aggression and mating behavior. critically, however, copulation frequency in primates is not always predictive of reproductive succe ...	2014	25454788
the social life of laughter.	laughter is often considered to be the product of humour. however, laughter is a social emotion, occurring most often in interactions, where it is associated with bonding, agreement, affection, and emotional regulation. laughter is underpinned by complex neural systems, allowing it to be used flexibly. in humans and chimpanzees, social (voluntary) laughter is distinctly different from evoked (involuntary) laughter, a distinction which is also seen in brain imaging studies of laughter.	2014	25439499
early social exposure in wild chimpanzees: mothers with sons are more gregarious than mothers with daughters.	in many mammals, early social experience is critical to developing species-appropriate adult behaviors. although mother-infant interactions play an undeniably significant role in social development, other individuals in the social milieu may also influence infant outcomes. additionally, the social skills necessary for adult success may differ between the sexes. in chimpanzees (pan troglodytes), adult males are more gregarious than females and rely on a suite of competitive and cooperative relati ...	2014	25422411
sperm preservation by freeze-drying for the conservation of wild animals.	sperm preservation is a useful technique for the maintenance of biological resources in experimental and domestic animals, and in wild animals. a new preservation method has been developed that enables sperm to be stored for a long time in a refrigerator at 4 °c. sperm are freeze-dried in a solution containing 10 mm tris and 1 mm edta. using this method, liquid nitrogen is not required for the storage and transportation of sperm. we demonstrate that chimpanzee, giraffe, jaguar, weasel and the lo ...	2014	25409172
sequence differences at orthologous microsatellites inflate estimates of human-chimpanzee differentiation.	microsatellites--contiguous arrays of 2-6 base-pair motifs--have formed the cornerstone of population-genetic studies for over two decades. their genotype data typically takes the form of pcr fragment lengths obtained using locus-specific primer pairs to amplify the genomic region encompassing the microsatellite. recently, we reported a dataset of 5,795 human and 84 chimpanzee individuals with genotypes at 246 human-derived autosomal microsatellites as a resource to facilitate interspecies compa ...	2014	25407736
human-chimpanzee alignment: ortholog exponentials and paralog power laws.	genomic subsequences conserved between closely related species such as human and chimpanzee exhibit an exponential length distribution, in contrast to the algebraic length distribution observed for sequences shared between distantly related genomes. we find that the former exponential can be further decomposed into an exponential component primarily composed of orthologous sequences, and a truncated algebraic component primarily composed of paralogous sequences.	2014	25443749
the origin of representational drawing: a comparison of human children and chimpanzees.	to examine the evolutional origin of representational drawing, two experiments directly compared the drawing behavior of human children and chimpanzees. the first experiment observed free drawing after model presentation, using imitation task. from longitudinal observation of humans (n = 32, 11-31 months), the developmental process of drawing until the emergence of shape imitation was clarified. adult chimpanzees showed the ability to trace a model, which was difficult for humans who had just st ...	2014	25376268
what did you choose just now? chimpanzees' short-term retention of memories of their own behavior.	many recent comparative studies have addressed "episodic" memory in nonhuman animals, suggesting that birds, rodents, great apes, and others can remember their own behavior after at least a half-day delay. by contrast, despite numerous studies regarding long-term memory, few comparable studies have been conducted on short-term retention for own behavior. in the current study, we addressed the following question: do chimpanzees remember what they have just done? four chimpanzees performed matchin ...	2014	25374781
the relationship between event-based prospective memory and ongoing task performance in chimpanzees (pan troglodytes).	prospective memory is remembering to do something at a future time. a growing body of research supports that prospective memory may exist in nonhuman animals, but the methods used to test nonhuman prospective memory differ from those used with humans. the current work tests prospective memory in chimpanzees using a method that closely approximates a typical human paradigm. in these experiments, the prospective memory cue was embedded within an ongoing task. tokens representing food items could b ...	2014	25372809
mouse models of human evolution.	the genotype-phenotype map of human evolution is difficult to access since humans cannot be crossed with other species. most of the ∼20 million genetic changes that occurred since the human and the chimpanzee lineage split, are fixed and hence completely correlated with all phenotypic changes that occurred during human evolution. while patterns of selection and functional information on genomic regions are crucial to prioritize on particular genetic changes, experimental access is needed to test ...	2014	25218860
the role of gene regulatory factors in the evolutionary history of humans.	deciphering the molecular basis of how modern human phenotypes have evolved is one of the most fascinating challenges in biology. here, we will focus on the roles of gene regulatory factors (grfs), in particular transcription factors (tfs) and long non-coding rnas (lncrnas) during human evolution. we will present examples of tfs and lncrnas that have changed or show signs of positive selection in humans compared to chimpanzees, in modern humans compared to archaic humans, or within modern human ...	2014	25215414
evaluating the y chromosomal timescale in human demographic and lineage dating.	y chromosome is a superb tool for inferring human evolution and recent demographic history from a paternal perspective. however, y chromosomal substitution rates obtained using different modes of calibration vary considerably, and have produced disparate reconstructions of human history. here, we discuss how substitution rate and date estimates are affected by the choice of different calibration points. we argue that most y chromosomal substitution rates calculated to date have shortcomings, inc ...	2014	25215184
fish choose appropriately when and with whom to collaborate.	collaborative abilities are integral to human society [1] and their evolutionary origins are of great interest. chimpanzees are capable of determining appropriately when and with whom to collaborate in a rope-pull experiment [2]--the only non-human species known to possess both abilities. chimpanzees are thought to share these abilities with humans as a result of common ancestry [2]. here, we show that a fish--the coral trout plectropomus leopardus--has partner-choice abilities comparable to tho ...	2014	25202866
alloparenting for chimpanzee twins.	in april 2009, a female chimpanzee named sango, living in a captive group at the noichi zoo, japan, gave birth to dizygotic male-female twin chimpanzees (male: daiya, female: sakura). the extent to which adult group members cared for the twins was investigated using a focal animal sampling method targeting six adults (one male) when the twin chimpanzees were two years old. data were collected for an average of 6.78 h (sd = 0.79) per focal participant. an unaffiliated female adult of sango was en ...	2014	25200656
identification of species-specific nuclear insertions of mitochondrial dna (numts) in gorillas and their potential as population genetic markers.	the first hyper-variable region (hv1) of the mitochondrial control region (mcr) has been widely used as a molecular tool in population genetics, but inadvertent amplification of nuclear translocated copies of mitochondrial dna (numts) in gorillas has compromised the use of mitochondrial dna in population genetic studies. at least three putative classes (i, ii, iii) of gorilla-specific hv1 mcr numts have been uncovered over the past decade. however, the number, size and location of numt loci in g ...	2014	25194325
task design influences prosociality in captive chimpanzees (pan troglodytes).	chimpanzees confer benefits on group members, both in the wild and in captive populations. experimental studies of how animals allocate resources can provide useful insights about the motivations underlying prosocial behavior, and understanding the relationship between task design and prosocial behavior provides an important foundation for future research exploring these animals' social preferences. a number of studies have been designed to assess chimpanzees' preferences for outcomes that benef ...	2014	25191860
the paleoecology of early pleistocene gigantopithecus blacki inferred from isotopic analyses.	this study presents isotopic analyses of gigantopithecus blacki and contemporaneous fauna from early pleistocene southern china cave localities with a view to reconstructing the paleoecology of this large extinct ape. carbon and oxygen stable isotope compositions were determined using tooth enamel carbonate of gigantopithecus and eight other taxa from longgudong cave and additional gigantopithecus specimens from juyuandong cave. carbon isotopic values of gigantopithecus fauna reflect a densely f ...	2014	25181425
towards a unified scheme of cortical lamination for primary visual cortex across primates: insights from neun and vglut2 immunoreactivity.	primary visual cortex (v1) is clearly distinguishable from other cortical areas by its distinctive pattern of neocortical lamination across mammalian species. in some mammals, primates in particular, the layers of v1 are further divided into a number of sublayers based on their anatomical and functional characteristics. while these sublayers are easily recognizable across a range of primates, the exact number of divisions in each layer and their relative position within the depth of v1 has been ...	2014	25177277
exploring the genesis and functions of human accelerated regions sheds light on their role in human evolution.	human accelerated regions (hars) are dna sequences that changed very little throughout mammalian evolution, but then experienced a burst of changes in humans since divergence from chimpanzees. this unexpected evolutionary signature is suggestive of deeply conserved function that was lost or changed on the human lineage. since their discovery, the actual roles of hars in human evolution have remained somewhat elusive, due to their being almost exclusively non-coding sequences with no annotation. ...	2014	25156517
adult humans' understanding of support relations: an up-linkage replication.	in an up-linkage replication, three experiments examined adult humans' folk physics, i.e., their naturally occurring and spontaneous understanding of the physical world, using a violation of expectation (voe) task and stimuli similar to those used to study chimpanzees', monkeys', and rooks' folk physics. unlike what has been reported with nonhuman primates, adult humans did not look longer at physically impossible than possible events, though they did rate the physically impossible events as mor ...	2014	25149282
chimpanzees (pan troglodytes) instrumentally help but do not communicate in a mutualistic cooperative task.	chimpanzees cooperate in a variety of contexts, but communicating to influence and regulate cooperative activities is rare. it is unclear whether this reflects chimpanzees' general inability or whether they have found other means to coordinate cooperative activities. in the present study chimpanzees could help a partner play her role in a mutually beneficial food-retrieval task either by transferring a needed tool (transfer condition) or by visually or acoustically communicating the hiding-locat ...	2014	25133465
the cortical microstructural basis of lateralized cognition: a review.	the presence of asymmetry in the human cerebral hemispheres is detectable at both the macroscopic and microscopic scales. the horizontal expansion of cortical surface during development (within individual brains), and across evolutionary time (between species), is largely due to the proliferation and spacing of the microscopic vertical columns of cells that form the cortex. in the asymmetric planum temporale (pt), minicolumn width asymmetry is associated with surface area asymmetry. although the ...	2014	25126082
the influence of body mass index, age and sex on inflammatory disease risk in semi-captive chimpanzees.	obesity and ageing are emerging issues in the management of captive primates, including chimpanzees, pan troglodytes. studies on humans show that obesity and old age can independently increase the risk of inflammatory-associated diseases indicated by elevated levels of pro-inflammatory cells and proteins in the blood of older or obese compared to levels in younger or non-obese individuals. in humans, sex can influence the outcomes of these risks. health management of these problems in chimpanzee ...	2014	25121995
nih finalizes chimpanzee housing requirements.		2014	25118460
finding faces among faces: human faces are located more quickly and accurately than other primate and mammal faces.	we tested the specificity of human face search efficiency by examining whether there is a broad window of detection for various face-like stimuli-human and animal faces-or whether own-species faces receive greater attentional allocation. we assessed the strength of the own-species face detection bias by testing whether human faces are located more efficiently than other animal faces, when presented among various other species' faces, in heterogeneous 16-, 36-, and 64-item arrays. across all arra ...	2014	25113852
playful expressions of one-year-old chimpanzee infants in social and solitary play contexts.	knowledge of the context and development of playful expressions in chimpanzees is limited because research has tended to focus on social play, on older subjects, and on the communicative signaling function of expressions. here we explore the rate of playful facial and body expressions in solitary and social play, changes from 12- to 15-months of age, and the extent to which social partners match expressions, which may illuminate a route through which context influences expression. naturalistic o ...	2014	25104942
improved calibration of the human mitochondrial clock using ancient genomes.	reliable estimates of the rate at which dna accumulates mutations (the substitution rate) are crucial for our understanding of the evolution and past demography of virtually any species. in humans, there are considerable uncertainties around these rates, with substantial variation among recent published estimates. substitution rates have traditionally been estimated by associating dated events to the root (e.g., the divergence between humans and chimpanzees) or to internal nodes in a phylogeneti ...	2014	25100861
why do chimpanzee males attack the females of neighboring communities?	our closest nonhuman primate relatives, chimpanzees, engage in potentially lethal between-group conflict; this collective aggressive behavior shows parallels with human warfare. in some communities, chimpanzee males also severely attack and even kill females of the neighboring groups. this is surprising given their system of resource defense polygyny, where males are expected to acquire potential mates. we develop a simple mathematical model based on reproductive skew among primate males to solv ...	2014	25100507
density estimates and nesting-site selection in chimpanzees of the nimba mountains, côte d'ivoire, and guinea.	we investigated nesting behavior of non habituated chimpanzees populating the nimba mountains to document their abundance and their criterions of nesting-site selection. during a 19-month study we walked 80 km of transects and recces each month, and recorded 764 nests (mean group size = 2.23 nests) along with characteristics of vegetation structure and composition, topography, and seasonality. population density estimated with two nest count methods ranged between 0.14 and 0.65 chimpanzee/km(2) ...	2014	25099739
'adoption' by maternal siblings in wild chimpanzees.	the adoption of unrelated orphaned infants is something chimpanzees and humans have in common. providing parental care has fitness implications for both the adopter and orphan, and cases of adoption have thus been cited as evidence for a shared origin of an altruistic behaviour. we provide new data on adoptions in the free-living sonso chimpanzee community in uganda, together with an analysis of published data from other long-term field sites. as a default pattern, we find that orphan chimpanzee ...	2014	25084521
hunter-gatherer inter-band interaction rates: implications for cumulative culture.	our species exhibits spectacular success due to cumulative culture. while cognitive evolution of social learning mechanisms may be partially responsible for adaptive human culture, features of early human social structure may also play a role by increasing the number potential models from which to learn innovations. we present interview data on interactions between same-sex adult dyads of ache and hadza hunter-gatherers living in multiple distinct residential bands (20 ache bands; 42 hadza bands ...	2014	25047714
modular structure facilitates mosaic evolution of the brain in chimpanzees and humans.	different brain components can evolve in a coordinated manner or they can show divergent evolutionary trajectories according to a mosaic pattern of variation. understanding the relationship between these brain evolutionary patterns, which are not mutually exclusive, can be informed by the examination of intraspecific variation. our study evaluates patterns of brain anatomical covariation in chimpanzees and humans to infer their influence on brain evolution in the hominin clade. we show that chim ...	2014	25047085
unraveling recombination rate evolution using ancestral recombination maps.	recombination maps of ancestral species can be constructed from comparative analyses of genomes from closely related species, exemplified by a recently published map of the human-chimpanzee ancestor. such maps resolve differences in recombination rate between species into changes along individual branches in the speciation tree, and allow identification of associated changes in the genomic sequences. we describe how coalescent hidden markov models are able to call individual recombination events ...	2014	25043668
hypothesis: brain size and skull shape as criteria for a new hominin family tree.	today, gorillas and chimpanzees live in tropical forests, where acid soils do not favor fossilization. it is thus widely believed that there are no fossils of chimpanzees or gorillas. however, four teeth of a 0.5-million-year (ma)-old chimpanzee were discovered in the rift valley of kenya (mcbrearty and jablonski, 2005), and a handful of teeth of a 10-ma-old gorilla-like creature were found in ethiopia (suwa et al., 2007), close to the major sites of homo discoveries. these discoveries indicate ...	2014	25041944
characterization of a genogroup i sapovirus isolated from chimpanzees in the republic of congo.	sapoviruses, which are members of the caliciviridae family, are small nonenveloped viruses known to infect a large spectrum of mammalian hosts. we report here the first complete genome sequences of two genogroup i sapoviruses isolated from fecal samples from chimpanzees living in the tchimpounga sanctuary, republic of congo.	2014	25035327
suitable habitats for endangered frugivorous mammals: small-scale comparison, regeneration forest and chimpanzee density in kibale national park, uganda.	landscape patterns and chimpanzee (pan troglodytes schweinfurthii) densities in kibale national park show important variation among communities that are geographically close to one another (from 1.5 to 5.1 chimpanzees/km2). anthropogenic activities inside the park (past logging activities, current encroachment) and outside its limits (food and cash crops) may impact the amount and distribution of food resources for chimpanzees (frugivorous species) and their spatial distribution within the park. ...	2014	25033459
recombination in the human pseudoautosomal region par1.	the pseudoautosomal region (par) is a short region of homology between the mammalian x and y chromosomes, which has undergone rapid evolution. a crossover in the par is essential for the proper disjunction of x and y chromosomes in male meiosis, and par deletion results in male sterility. this leads the human par with the obligatory crossover, par1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. however, the mechanism by which this obli ...	2014	25033397
uncovering adaptive evolution in the human lineage.	the recent increase in human polymorphism data, together with the availability of genome sequences from several primate species, provides an unprecedented opportunity to investigate how natural selection has shaped human evolution.	2014	25030307
chimpanzee intelligence is heritable.	the role that genes play in human intelligence or iq has remained a point of significant scientific debate dating back to the time of galton [1]. it has now become increasingly clear that iq is heritable in humans, but these effects can be modified by nongenetic mechanisms [2-4]. in contrast to human iq, until recently, views of learning and cognition in animals have largely been dominated by the behaviorist school of thought, originally championed by watson [5] and skinner [6]. a large body of ...	2014	25017206
the meanings of chimpanzee gestures.	chimpanzees' use of gesture was described in the first detailed field study [1, 2], and natural use of specific gestures has been analyzed [3-5]. however, it was systematic work with captive groups that revealed compelling evidence that chimpanzees use gestures to communicate in a flexible, goal-oriented, and intentional fashion [6-8], replicated across all great ape species in captivity [9-17] and chimpanzees in the wild [18, 19]. all of these aspects overlap with human language but are apparen ...	2014	24998524
chimpanzee isotopic ecology: a closed canopy c3 template for hominin dietary reconstruction.	the most significant hominin adaptations, including features used to distinguish and/or classify taxa, are critically tied to the dietary environment. stable isotopic analyses of tooth enamel from hominin fossils have provided intriguing evidence for significant c4/cam (crassulacean acid metabolism) resource consumption in a number of plio-pleistocene hominin taxa. relating isotopic tooth signatures to specific dietary items or proportions of c3 versus c4/cam plants, however, remains difficult a ...	2014	24993419
chimpanzees (pan troglodytes verus) and their mammalian sympatriates: mt. assirik, niokolo-koba national park, senegal.	in intact, mosaic ecosystems, chimpanzees are sympatric with a wide range of other mammals, which may be predators, prey, or competitors. we delve beyond the nominal data of species lists to interval-level data on 35 medium-bodied and large-bodied mammals encountered at a hot, dry, and open field site in far west africa. frequency of encounter, habitat where found, and number of individuals encountered are analysed for species for which enough data were accumulated. further, we compare findings ...	2014	24990446
the importance of social play network for infant or juvenile wild chimpanzees at mahale mountains national park, tanzania.	along with social grooming and food sharing, social play is considered to be an affiliative interaction among wild chimpanzees. however, infant, juvenile, and adolescent animals engage in social play more frequently than adult animals, while other affiliative interactions occur more commonly between adults. we studied the social play of well-habituated and individually identified wild chimpanzees of the m group in mahale mountains national park, tanzania over two research periods in 2010 and 201 ...	2014	24990324
chimpanzee-specific endogenous retrovirus generates genomic variations in the chimpanzee genome.	endogenous retroviruses (ervs), eukaryotic transposable elements, exist as proviruses in vertebrates including primates and contribute to genomic changes during the evolution of their host genomes. many studies about ervs have focused on the elements residing in the human genome but only a few studies have focused on the elements which exist in non-human primate genomes. in this study, we identified 256 chimpanzee-specific endogenous retrovirus copies (ptervs: pan troglodyte endogenous retroviru ...	2014	24987855
scanning electron microscopy of the hair medulla of orangutan, chimpanzee, and man.		2014	24985515
age-related effects in the neocortical organization of chimpanzees: gray and white matter volume, cortical thickness, and gyrification.	among primates, humans exhibit the most profound degree of age-related brain volumetric decline in particular regions, such as the hippocampus and the frontal lobe. recent studies have shown that our closest living relatives, the chimpanzees, experience little to no volumetric decline in gray and white matter over the adult lifespan. however, these previous studies were limited with a small sample of chimpanzees of the most advanced ages. in the present study, we sought to further test for poten ...	2014	24983715
a universal genomic coordinate translator for comparative genomics.	genomic duplications constitute major events in the evolution of species, allowing paralogous copies of genes to take on fine-tuned biological roles. unambiguously identifying the orthology relationship between copies across multiple genomes can be resolved by synteny, i.e. the conserved order of genomic sequences. however, a comprehensive analysis of duplication events and their contributions to evolution would require all-to-all genome alignments, which increases at n2 with the number of avail ...	2014	24976580
the apparent enhancement of cpg transversions in primate lineage is a consequence of multiple replacements.	we claim that the apparently enhanced cpg transversions in the form cpg to cpc/gpg or to apg/cpt are caused by the hypermutable cpg to cpa/tpg transition. the nucleotide replacement counts obtained from the human/chimpanzee/gorilla/orangutan sequence alignments representing the replacements due to the evolutionary species divergence and the results of 1000 genomes project that provide us with the differences due to the intraspecies diversification were analyzed to estimate the ratio of cpg versu ...	2014	24969749
spontaneous leiomyomas of the gastroesophageal junction in a chimpanzee (pan troglodytes).	a 49-y-old, female chimpanzee presented with a history of cardiac failure. postmortem examination revealed lesions consistent with congestive heart failure and 2 incidental, round, firm, pale-tan intramural nodules (diameter, 2 cm) in the stomach at the gastroesophageal junction (gej). histologically, the gej nodules were diagnosed as benign spindle-cell tumors. immunohistochemical evaluation revealed neoplastic cells diffusely labeled with α-smooth muscle actin and vimentin, multifocally labele ...	2014	24956216
taï chimpanzees anticipate revisiting high-valued fruit trees from further distances.	the use of spatio-temporal memory has been argued to increase food-finding efficiency in rainforest primates. however, the exact content of this memory is poorly known to date. this study investigated what specific information from previous feeding visits chimpanzees (pan troglodytes verus), in taï national park, côte d'ivoire, take into account when they revisit the same feeding trees. by following five adult females for many consecutive days, we tested from what distance the females directed t ...	2014	24950721
ape duos and trios: spontaneous cooperation with free partner choice in chimpanzees.	the purpose of the present study was to push the boundaries of cooperation among captive chimpanzees (pan troglodytes). there has been doubt about the level of cooperation that chimpanzees are able to spontaneously achieve or understand. would they, without any pre-training or restrictions in partner choice, be able to develop successful joint action? and would they be able to extend cooperation to more than two partners, as they do in nature? chimpanzees were given a chance to cooperate with mu ...	2014	24949236
variability in premolar and molar root number in a modern population of pan troglodytes verus.	while teeth are the most common fossil remains for hominoids, little is known of the tooth root morphology in primates. with the exception of modern humans, the variability of the number of roots within a species is scarcely documented and not conclusively quantified. this lack of knowledge hinders the interpretation of observed evolutionary trends, such as the reduction of the number of roots of premolars within the hominins. here, we present the first quantification of the variability of the n ...	2014	24948571
chimpanzee update.		2014	24937921
translating the immunogenicity of prime-boost immunization with chad63 and mva me-trap from malaria naive to malaria-endemic populations.	to induce a deployable level of efficacy, a successful malaria vaccine would likely benefit from both potent cellular and humoral immunity. these requirements are met by a heterologous prime-boost immunization strategy employing a chimpanzee adenovirus vector followed by modified vaccinia ankara (mva), both encoding the pre-erythrocytic malaria antigen me-thrombospondin-related adhesive protein (trap), with high immunogenicity and significant efficacy in uk adults. we undertook two phase 1b open ...	2014	24930599
from cultural traditions to cumulative culture: parameterizing the differences between human and nonhuman culture.	diverse species exhibit cultural traditions, i.e. population-specific profiles of socially learned traits, from songbird dialects to primate tool-use behaviours. however, only humans appear to possess cumulative culture, in which cultural traits increase in complexity over successive generations. theoretically, it is currently unclear what factors give rise to these phenomena, and consequently why cultural traditions are found in several species but cumulative culture in only one. here, we addre ...	2014	24928150
nonhuman genetics. strong male bias drives germline mutation in chimpanzees.	germline mutation determines rates of molecular evolution, genetic diversity, and fitness load. in humans, the average point mutation rate is 1.2 × 10(-8) per base pair per generation, with every additional year of father's age contributing two mutations across the genome and males contributing three to four times as many mutations as females. to assess whether such patterns are shared with our closest living relatives, we sequenced the genomes of a nine-member pedigree of western chimpanzees, p ...	2014	24926018
analysis of joint force and torque for the human and non-human ape foot during bipedal walking with implications for the evolution of the foot.	the feet of apes have a different morphology from those of humans. until now, it has merely been assumed that the morphology seen in humans must be adaptive for habitual bipedal walking, as the habitual use of bipedal walking is generally regarded as one of the most clear-cut differences between humans and apes. this study asks simply whether human skeletal proportions do actually enhance foot performance during human-like bipedalism, by examining the influence of foot proportions on force, torq ...	2014	24925580
estimation of the ancestral effective population sizes of african great apes under different selection regimes.	reliable estimates of ancestral effective population sizes are necessary to unveil the population-level phenomena that shaped the phylogeny and molecular evolution of the african great apes. although several methods have previously been applied to infer ancestral effective population sizes, an analysis of the influence of the selective regime on the estimates of ancestral demography has not been thoroughly conducted. in this study, three independent data sets under different selective regimes we ...	2014	24925265
synchrony and motor mimicking in chimpanzee observational learning.	cumulative tool-based culture underwrote our species' evolutionary success, and tool-based nut-cracking is one of the strongest candidates for cultural transmission in our closest relatives, chimpanzees. however the social learning processes that may explain both the similarities and differences between the species remain unclear. a previous study of nut-cracking by initially naïve chimpanzees suggested that a learning chimpanzee holding no hammer nevertheless replicated hammering actions it wit ...	2014	24923651
novel h3k4me3 marks are enriched at human- and chimpanzee-specific cytogenetic structures.	human and chimpanzee genomes are 98.8% identical within comparable sequences. however, they differ structurally in nine pericentric inversions, one fusion that originated human chromosome 2, and content and localization of heterochromatin and lineage-specific segmental duplications. the possible functional consequences of these cytogenetic and structural differences are not fully understood and their possible involvement in speciation remains unclear. we show that subtelomeric regions--regions t ...	2014	24916972
a group-specific arbitrary tradition in chimpanzees (pan troglodytes).	social learning in chimpanzees has been studied extensively and it is now widely accepted that chimpanzees have the capacity to learn from conspecifics through a multitude of mechanisms. very few studies, however, have documented the existence of spontaneously emerged traditions in chimpanzee communities. while the rigour of experimental studies is helpful to investigate social learning mechanisms, documentation of naturally occurring traditions is necessary to understand the relevance of social ...	2014	24916739
evolutionary origin and human-specific expansion of a cancer/testis antigen gene family.	cancer/testis (ct) antigens are encoded by germline genes and are aberrantly expressed in a number of human cancers. interestingly, ct antigens are frequently involved in gene families that are highly expressed in germ cells. here, we presented an evolutionary analysis of the ctage (cutaneous t-cell-lymphoma-associated antigen) gene family to delineate its molecular history and functional significance during primate evolution. comparisons among human, chimpanzee, gorilla, orangutan, macaque, mar ...	2014	24916032
spatial relationship between the mental foramen and mandibular developing teeth in modern humans, chimpanzees, and hamadryas baboons.	the mental foramen (mf) of adult human mandibles is characterized by its high position and posterosuperior opening orientation, compared with that of nonhuman primates. in this study, to examine when and how such interspecies variations in mf position/orientation are manifested in the context of dental development, positional relationships between the mf and nearby forming teeth (dc, dm1, c, p3) were assessed using ct-scanned growth-series mandibles of the following three species with various mf ...	2014	24913892
dietary history contributes to enterotype-like clustering and functional metagenomic content in the intestinal microbiome of wild mice.	understanding the origins of gut microbial community structure is critical for the identification and interpretation of potential fitness-related traits for the host. the presence of community clusters characterized by differences in the abundance of signature taxa, referred to as enterotypes, is a debated concept first reported in humans and later extended to other mammalian hosts. in this study, we provide a thorough assessment of their existence in wild house mice using a panel of evaluation ...	2014	24912178
analysis of candidate genes for lineage-specific expression changes in humans and primates.	runx2, a gene involved in skeletal development, has previously been shown to be potentially affected by positive selection during recent human evolution. here we have used antibody-based proteomics to characterize potential differences in expression patterns of runx2 interacting partners during primate evolution. tissue microarrays consisting of a large set of normal tissues from human and macaque were used for protein profiling of 50 runx2 partners with immunohistochemistry. eleven proteins (ar ...	2014	24911366
sex differences in wild chimpanzee behavior emerge during infancy.	the role of biological and social influences on sex differences in human child development is a persistent topic of discussion and debate. given their many similarities to humans, chimpanzees are an important study species for understanding the biological and evolutionary roots of sex differences in human development. in this study, we present the most detailed analyses of wild chimpanzee infant development to date, encompassing data from 40 infants from the long-term study of chimpanzees at gom ...	2014	24911160
reduced binding of human antibodies to cells from ggta1/cmah ko pigs.	xenotransplantation using genetically modified pig organs could solve the donor organ shortage problem. two inactivated genes that make humans unique from pigs are ggta1 and cmah, the products of which produce the carbohydrate epitopes, agal and neu5gc that attract preformed human antibody. when the ggta1 and cmah genes were deleted in pigs, human antibody binding was reduced in preliminary analysis. we analyzed the binding of human igm and igg from 121 healthy human serum samples for binding to ...	2014	24909344