| re-emergence of the leaf clip gesture during an alpha takeover affects variation in male chimpanzee loud calls. | loud calls are used by many species as long-distance signals for group defense, mate attraction, and inter- and intragroup spacing. chimpanzee loud calls, or pant hoots, are used in a variety of contexts including group coordination and during male contests. here, we observed an alpha male takeover in wild chimpanzees (pan troglodytes verus) during which the leaf clipping gesture re-emerged after disappearing for almost two years in this community. leaf clipping only occurred in males and was ob ... | 2018 | 29967740 |
| factors influencing bacterial microbiome composition in a wild non-human primate community in taï national park, côte d'ivoire. | microbiomes impact a variety of processes including a host's ability to access nutrients and maintain health. while host species differences in microbiomes have been described across ecosystems, little is known about how microbiomes assemble, particularly in the ecological and social contexts in which they evolved. we examined gut microbiome composition in nine sympatric wild non-human primate (nhp) species. despite sharing an environment and interspecific interactions, individuals harbored uniq ... | 2018 | 29955140 |
| chimpanzee quiet hoo variants differ according to context. | in comparative studies of evolution of communication, the function and use of animal quiet calls have typically been understudied, despite that these signals are presumably under selection like other vocalizations, such as alarm calls. here, we examine vocalization diversification of chimpanzee quiet 'hoos' produced in three contexts-travel, rest and alert-and potential pressures promoting diversification. previous playback and observational studies have suggested that the overarching function o ... | 2018 | 29892396 |
| unusual dental morphology in a chimpanzee: a case report utilizing cone-beam computed tomography. | this case report illustrates the teeth morphology of a chimpanzee and its anatomical variations. a well-preserved skull of a male pan troglodytes troglodyte chimpanzee was scanned using a cone-beam computed tomography machine. measurements included tooth and crown height, root length, root canal length and width (posterior teeth), and pulp cavity length (anterior teeth). nonmetrical parameters included number of canals and foramina per root of every root. interestingly, the mandibular central in ... | 2018 | 29865987 |
| chimpanzees consider humans' psychological states when drawing statistical inferences. | great apes have been shown to be intuitive statisticians: they can use proportional information within a population to make intuitive probability judgments about randomly drawn samples [1, j.e., j.c., j.h., e.h., and h.r., unpublished data]. humans, from early infancy onward, functionally integrate intuitive statistics with other cognitive domains to judge the randomness of an event [2-6]. to date, nothing is known about such cross-domain integration in any nonhuman animal, leaving uncertainty a ... | 2018 | 29861138 |
| is genetic drift to blame for testicular dysgenesis syndrome in semliki chimpanzees (pan troglodytes schweinfurthii)? | we present 3 likely cases of testicular dysgenesis syndrome (tds) within a community of chimpanzees (pan troglodytes schweinfurthii). we tested whether genetic drift may be the culprit, as a genetic cause has been suspected to account for tds among other wildlife. | 2018 | 29799118 |
| brain size growth in wild and captive chimpanzees (pan troglodytes). | despite many studies of chimpanzee brain size growth, intraspecific variation is under-explored. brain size data from chimpanzees of the taï forest and the yerkes primate research center enable a unique glimpse into brain growth variation as age at death is known for individuals, allowing cross-sectional growth curves to be estimated. because taï chimpanzees are from the wild but yerkes apes are captive, potential environmental effects on neural development can also be explored. previous researc ... | 2018 | 29797332 |
| morphological identification of hair recovered from feces for detection of cannibalism in eastern chimpanzees. | chimpanzees (pan troglodytes) are primarily frugivorous but consume a variable amount of meat from a variety of organisms, including other chimpanzees. cannibalism is rare, usually follows lethal aggression, and does not occur following natural deaths. while chimpanzee cannibalism has been documented at multiple sites, many instances of this behavior go unrecorded. identification of chimpanzee remains in feces, however, can provide indirect evidence of cannibalism. hair, in particular, typically ... | 2018 | 29788005 |
| the costs of living at the edge: seasonal stress in wild savanna-dwelling chimpanzees. | adaptations associated with shifting from a predominately forested habitat to a more open environment are considered a crucial step in hominin evolution. understanding how chimpanzees, one of our closest-living relatives, are exposed to the selection pressures associated with living in a relatively sparse, hot, and dry environment can inform us about the relative importance of potential environmental stressors involved in adaptations to drier environments. we investigated the extent to which chi ... | 2018 | 29685749 |
| structural and molecular study of the supraspinatus muscle of modern humans (homo sapiens) and common chimpanzees (pan troglodytes). | to analyze the muscle architecture and the expression pattern of the myosin heavy chain (myhc) isoforms in the supraspinatus of pan troglodytes and homo sapiens in order to identify differences related to their different types of locomotion. | 2018 | 29681126 |
| an evaluation of video cameras for collecting observational data on sanctuary-housed chimpanzees (pan troglodytes). | video cameras are increasingly being used to monitor captive animals in zoo, laboratory, and agricultural settings. this technology may also be useful in sanctuaries with large and/or complex enclosures. however, the cost of camera equipment and a lack of formal evaluations regarding the use of cameras in sanctuary settings make it challenging for facilities to decide whether and how to implement this technology. to address this, we evaluated the feasibility of using a video camera system to mon ... | 2018 | 29675871 |
| captive chimpanzees' manual laterality in tool use context: influence of communication and of sociodemographic factors. | understanding variations of apes' laterality between activities is a central issue when investigating the evolutionary origins of human hemispheric specialization of manual functions and language. we assessed laterality of 39 chimpanzees in a non-communication action similar to termite fishing that we compared with data on five frequent conspecific-directed gestures involving a tool previously exploited in the same subjects. we evaluated, first, population-level manual laterality for tool-use in ... | 2018 | 29665416 |
| captive chimpanzee (pan troglodytes) behavior as a function of space per animal and enclosure type. | space per animal, or animal density, and enclosure type are important elements of functionally appropriate captive environments (faces) for chimpanzees. the national institutes of health (nih) recommends that captive chimpanzees be maintained in areas of >250 ft2 /animal. several studies have investigated chimpanzee behavior in relation to space per animal, but only two studies have examined these variables while attempting to hold environmental complexity constant. both have found few, if any, ... | 2018 | 29575053 |
| chimpanzees prioritise social information over pre-existing behaviours in a group context but not in dyads. | how animal communities arrive at homogeneous behavioural preferences is a central question for studies of cultural evolution. here, we investigated whether chimpanzees (pan troglodytes) would relinquish a pre-existing behaviour to adopt an alternative demonstrated by an overwhelming majority of group mates; in other words, whether chimpanzees behave in a conformist manner. in each of five groups of chimpanzees (n = 37), one individual was trained on one method of opening a two-action puzzle box ... | 2018 | 29574554 |
| modeling habitat suitability for chimpanzees (pan troglodytes verus) in the greater nimba landscape, guinea, west africa. | tropical forests and the biodiversity within them are rapidly declining in the face of increasing human populations. resource management and conservation of endangered species requires an understanding of how species perceive and respond to their environments. species distribution modeling (sdm) is an appropriate tool for identifying conservation areas of concern and importance. in this study, sdm was used to identify areas of suitable chimpanzee (pan troglodytes verus) habitat within the greate ... | 2018 | 29524002 |
| tie one on: 'nest tying' by wild chimpanzees at bulindi-a variant of a universal great ape behavior? | with data accumulating from a growing pool of chimpanzee field studies, new behaviors as well as novel variants on common behaviors continue to be described. nest construction is a universal behavior in wild great apes. among chimpanzee populations, reported variation in nest building behavior mostly reflects environmental constraints. despite the ubiquity of nest making by chimpanzees, only ground nesting has been recognized as a behavioral variant, potentially determined by both environmental ... | 2018 | 29511901 |
| the effects of type i collagenase on the degelification of chimpanzee (pan troglodytes) semen plug and sperm quality. | semen from the chimpanzee species becomes a colloidal solid after ejaculation. the formation of this copulatory plug is believed to prevent additional spermatozoa of subsequent mating events from accessing the ova. however, this naturally preserved strategy hampers the processes for sperm preparation. in this study, we investigated whether collagenase can be used to degelify the semen plug and accelerate the semen liquefaction process in zoo captive chimpanzee species (pan troglodytes). | 2018 | 29482549 |
| chimpanzees (pan troglodytes) display limited behavioural flexibility when faced with a changing foraging task requiring tool use. | behavioural flexibility, the ability to alter behaviour in response to environmental feedback, and to relinquish previously successful solutions to problems, is a crucial ability in allowing organisms to adapt to novel environments and environmental change; it is essential to cumulative cultural change. to explore this ability in chimpanzees, 18 individuals (pan troglodytes) were presented with an artificial foraging task consisting of a tube partially filled with juice that could be reached by ... | 2018 | 29479495 |
| social network and dominance hierarchy analyses at chimpanzee sanctuary northwest. | different aspects of sociality bear considerable weight on the individual- and group-level welfare of captive nonhuman primates. social network analysis (sna) is a useful tool for gaining a holistic understanding of the dynamic social relationships of captive primate groups. gaining a greater understanding of captive chimpanzees through investigations of centrality, preferred and avoided relationships, dominance hierarchy, and social network diagrams can be useful in advising current management ... | 2018 | 29444112 |
| nocturnal behavior by a diurnal ape, the west african chimpanzee (pan troglodytes verus), in a savanna environment at fongoli, senegal. | i report on the nocturnal behavior of fongoli chimpanzees in a savanna mosaic during different seasons and lunar phases and test the hypothesis that hot daytime temperatures influence activity at night. i predicted that apes would be more active at night during periods of greater lunar illuminosity given diurnal primates' lack of visual specializations for low-light conditions and in dry season months when water scarcity exacerbated heat stress. | 2018 | 29417991 |
| gestural acquisition in great apes: the social negotiation hypothesis. | scientific interest in the acquisition of gestural signalling dates back to the heroic figure of charles darwin. more than a hundred years later, we still know relatively little about the underlying evolutionary and developmental pathways involved. here, we shed new light on this topic by providing the first systematic, quantitative comparison of gestural development in two different chimpanzee (pan troglodytes verus and pan troglodytes schweinfurthii) subspecies and communities living in their ... | 2019 | 29368287 |
| seasonal and inter-annual variation of malaria parasite detection in wild chimpanzees. | cross-sectional surveys of chimpanzee (pan troglodytes) communities across sub-saharan africa show large geographical variation in malaria parasite (plasmodium spp.) prevalence. the drivers leading to this apparent spatial heterogeneity may also be temporally dynamic but data on prevalence variation over time are missing for wild great apes. this study aims to fill this fundamental gap. | 2018 | 29347985 |
| the effects of social context and food abundance on chimpanzee feeding competition. | feeding competition is thought to play a role in primate social organization as well as cognitive evolution. for chimpanzees (pan troglodytes), social and ecological factors can affect competition, yet how these factors interact to affect feeding behavior is not fully understood; they can be difficult to disentangle in wild settings. this experiment investigated the differential effects of food quantity, the presence of a co-feeding partner, and the contestability of a food patch on feeding rate ... | 2018 | 29331042 |
| dna recovery from wild chimpanzee tools. | most of our knowledge of wild chimpanzee behaviour stems from fewer than 10 long-term field sites. this bias limits studies to a potentially unrepresentative set of communities known to show great behavioural diversity on small geographic scales. here, we introduce a new genetic approach to bridge the gap between behavioural material evidence in unhabituated chimpanzees and genetic advances in the field of primatology. the use of dna analyses has revolutionised archaeological and primatological ... | 2018 | 29298306 |
| savanna chimpanzee (pan troglodytes verus) nesting ecology at bagnomba (kedougou, senegal). | we studied the nesting behavior of the critically endangered west african chimpanzee (pan troglodytes verus). we assumed that the nesting data stemmed from a single, unhabituated community at the bagnomba hill site in the savanna-woodlands of southeastern senegal. the aim of this study was to examine chimpanzees' nesting habits in terms of the tree species utilized and sleeping nest heights. we recorded a total of 550 chimpanzee nests at bagnomba between january 2015 and december 2015. the chimp ... | 2018 | 29282580 |
| social relationship and hair cortisol level in captive male chimpanzees (pan troglodytes). | understanding how social relationships affect long-term stress is important because stress has a profound impact on the welfare of animals and social relationships often exert a strong influence on their stress responses. the purpose of this study was to investigate the relationship between social behaviors and long-term stress levels as assessed by hair cortisol (hc) concentration. the subjects were 11 chimpanzees living in an all-male group (divided into two sub-groups) in kumamoto sanctuary, ... | 2018 | 29247286 |
| changes in frontoparietotemporal connectivity following do-as-i-do imitation training in chimpanzees ( pan troglodytes). | human imitation is supported by an underlying "mirror system" principally composed of inferior frontal, inferior parietal, and superior temporal cortical regions. across primate species, differences in frontoparietotemporal connectivity have been hypothesized to explain phylogenetic variation in imitative abilities. however, if and to what extent these regions are involved in imitation in nonhuman primates is unknown. we hypothesized that "do as i do" (daid) imitation training would enhance whit ... | 2018 | 29211652 |
| zoonotic enterobacterial pathogens detected in wild chimpanzees. | infectious diseases including those acquired through direct or indirect contact with people and livestock threaten the survival of wild great apes. few studies have reported enterobacterial pathogens in chimpanzees. we used multiplex pcr to screen faeces of chimpanzees sharing a landscape with villagers and livestock in bulindi, uganda for salmonella spp., enterohemorrhagic escherichia coli (e. coli) and shigella spp./enteroinvasive e. coli. all three potentially zoonotic pathogens were detected ... | 2018 | 29192342 |
| testing differential use of payoff-biased social learning strategies in children and chimpanzees. | various non-human animal species have been shown to exhibit behavioural traditions. importantly, this research has been guided by what we know of human culture, and the question of whether animal cultures may be homologous or analogous to our own culture. in this paper, we assess whether models of human cultural transmission are relevant to understanding biological fundamentals by investigating whether accounts of human payoff-biased social learning are relevant to chimpanzees (pan troglodytes). ... | 2017 | 29187629 |
| the relationship between social play and developmental milestones in wild chimpanzees (pan troglodytes schweinfurthii). | social play is common among many group-living animals, but the benefits are not well understood. proposed benefits include increased muscle coordination as the result of increased locomotor versatility and development, and strengthened social bonds through interactions with like-aged individuals. in this study, we used 33 years of long-term behavioral data on infant chimpanzees in gombe national park, tanzania, to examine these potential benefits of social play, specifically how the percentage o ... | 2017 | 29168188 |
| novice chimpanzees cooperate successfully in the presence of experts, but may have limited understanding of the task. | despite many observations of cooperation in nature, laboratory studies often fail to find careful coordination between individuals who are solving a cooperative task. further, individuals tested are often naïve to cooperative tasks and there has been little exploration of partnerships with mixed expertise. in the current study, we examined acquisition of a cooperative pulling task in a group with both expert (n = 4) and novice (n = 11) chimpanzees (pan troglodytes). we used five measures of comp ... | 2018 | 29147914 |
| trade-offs in the production of animal vocal sequences: insights from the structure of wild chimpanzee pant hoots. | vocal sequences - utterances consisting of calls produced in close succession - are common phenomena in animal communication. while many studies have explored the adaptive benefits of producing such sequences, very little is known about how the costs and constraints involved in their production affect their form. here, we investigated this issue in the chimpanzee (pan troglodytes schweinfurthii) pant hoot, a long and structurally complex vocal sequence comprising four acoustically distinct phase ... | 2017 | 29142585 |
| the higher the farther: distance-specific referential gestures in chimpanzees (pan troglodytes). | referential signals, such as manual pointing or deictic words, allow individuals to efficiently locate a specific entity in the environment, using distance-specific linguistic and/or gestural units. to explore the evolutionary prerequisites of such deictic ability, the present study investigates the ability of chimpanzees to adjust their communicative signals to the distance of a referent. a food-request paradigm in which the chimpanzees had to request a close or distant piece of food on a table ... | 2017 | 29142043 |
| infanticide in chimpanzees: taphonomic case studies from gombe. | we present a study of skeletal damage to four chimpanzee (pan troglodytes) infanticide victims from gombe national park, tanzania. skeletal analysis may provide insight into the adaptive significance of infanticide by examining whether nutritional benefits sufficiently explain infanticidal behavior. the nutritional hypothesis would be supported if bone survivorship rates and skeletal damage patterns are comparable to those of monkey prey. if not, other explanations, such as the resource competit ... | 2018 | 29072310 |
| personality in the chimpanzees of gombe national park. | researchers increasingly view animal personality traits as products of natural selection. we present data that describe the personalities of 128 eastern chimpanzees (pan troglodytes schweinfurthii) currently living in or who lived their lives in the kasekela and mitumba communities of gombe national park, tanzania. we obtained ratings on 24 items from an established, reliable, well-validated questionnaire used to study personality in captive chimpanzee populations. ratings were made by former an ... | 2017 | 29064463 |
| the diet of open-habitat chimpanzees (pan troglodytes schweinfurthii) in the issa valley, western tanzania. | comparative data on the diets of extant primates inform hypotheses about hominin resource use. historically, data describing chimpanzee diets stem primarily from forest-dwelling communities, and we lack comparative data from chimpanzees that live in mosaic habitats that more closely resemble those reconstructed for plio-pleistocene hominins. we present data on the diet of a partially-habituated community of open habitat chimpanzees (pan troglodytes schweinfurthii) from the issa valley, western t ... | 2017 | 29037416 |
| chimpanzee vertebrate consumption: savanna and forest chimpanzees compared. | there is broad consensus among paleoanthropologists that meat-eating played a key role in the evolution of homo, but the details of where, when, and why are hotly debated. it has been argued that increased faunivory was causally connected with hominin adaptation to open, savanna habitats. if savanna-dwelling chimpanzees eat meat more frequently than do forest chimpanzees, it would support the notion that open, dry, seasonal habitats promote hunting or scavenging by hominoids. here we present obs ... | 2017 | 29037414 |
| limited evidence for third-party affiliation during development in wild chimpanzees (pan troglodytes schweinfurthii). | examining the ontogeny of conflict-mitigating behaviours in our closest living relatives is an important component of understanding the evolutionary origins of cooperation in our species. in this study, we used 26 years of data to investigate the emergence of third-party affiliation (tpa), defined as affiliative contact given to recipients of aggression by uninvolved bystanders (regardless of initiation), in wild immature eastern chimpanzees (pan troglodytes schweinfurthii) of gombe national par ... | 2017 | 28989757 |
| a newborn infant chimpanzee snatched and cannibalized immediately after birth: implications for "maternity leave" in wild chimpanzee. | this study reports on the first observed case of a wild chimpanzee infant being snatched immediately after delivery and consequently cannibalized by an adult male in the mahale mountains, tanzania. we demonstrate "maternity leave" from long-term data from the mahale m group and suggest that it functions as a possible counterstrategy of mother chimpanzees against the risk of infanticide soon after delivery. | 2018 | 28983906 |
| the development of feeding behavior in wild chimpanzees (pan troglodytes schweinfurthii). | primates have an extended period of juvenility before adulthood. although dietary complexity plays a prominent role in hypotheses regarding the evolution of extended juvenility, the development of feeding behavior is still poorly understood. indeed, few studies have investigated the timing and nature of feeding transitions in apes, including chimpanzees. we describe general patterns of feeding development in wild chimpanzees and evaluate predictions of the needing-to-learn hypothesis. | 2018 | 28949015 |
| heart rate and indirect blood pressure responses to four different field anesthetic protocols in wild-born captive chimpanzees (pan troglodytes). | limited data are available on hemodynamic responses to anesthetic protocols in wild-born chimpanzees (pan troglodytes). accordingly, this study characterized the heart rate (hr) and blood pressure responses to four anesthetic protocols in 176 clinically healthy, wild-born chimpanzees undergoing routine health assessments. animals were anesthetized with medetomidine-ketamine (mk) (n = 101), tiletamine-zolazepam (tz) (n = 30), tiletamine-zolazepam-medetomidine (tzm) (n = 24), or medetomidine-ketam ... | 2017 | 28920777 |
| risk sensitivity, phylogenetic reconstruction, and four chimpanzees. | sensitivity to variance, or risk, has been considered elementary to economic decision making, featured prominently in discussions of primate species-typical behaviors and phylogeny, and heralded as a challenge to deterministic foraging theory. most risk sensitivity studies involve dichotomous choices and small spatial scales, providing only limited bases for predicting how variance information might be used across contexts. we examined foraging risk-sensitivity in four chimpanzees (pan troglodyt ... | 2017 | 32549648 |
| morphology of the lingual papillae in the chimpanzee. | we microscopically examined the dorsal lingual surface of an adult chimpanzee (pan troglodytes). the tongue of the chimpanzee was about 13 cm long. filiform papillae were distributed over the entire dorsal surface of the lingual body. there were many fungiform papillae scattered among the filiform papillae. at the posterior end of the lingual body, a triangular arrangement of the vallate papillae, with the apex of the triangle directed posteriorly, was observed. the filiform papillae on the ling ... | 2017 | 29681589 |
| social scratch: another custom in wild chimpanzees? | chimpanzees (pan troglodytes schweinfurthii) in the mahale mountains national park, tanzania, scratch other individual's bodies while they groom them. this behavioral pattern of "social scratch" is another example of locality-specific social behavior, or custom, as it is not found in the gombe national park, tanzania, about 150 km north of mahale, nor has it been reported from any other sites of chimpanzee study. frequency of social scratch was correlated with frequency of social grooming, but n ... | 2000 | 30545176 |
| paternity determination, genetic characterization, and social correlates in a captive group of chimpanzees (pan troglodytes). | in this study we use genetic fingerprints based on highly polymorphic microsatellite loci for paternity identification, apply some descriptive genetic measures and test social correlates of reproductive success in a group of captive chimpanzees. using 6 microsatellites applied to 34 blood or muscle samples, we inferred sires for 16 offspring. mean allele-sharing values revealed an increase in genetic relatedness from founder animals to animals born in the colony. multi-dimensional scaling of gen ... | 2000 | 30545168 |
| ant dipping and meat eating by wild chimpanzees in the kalinzu forest, uganda. | new evidence of ant dipping and meat eating by chimpanzees was recorded in the kalinzu forest, uganda. we found stems and branches at the nests of driver ants,dorylus molestus, just after chimpanzees had left the spot. fecal samples also revealed that chimpanzees sometimes ate driver ants. the configuration of stems and branches and the condition of holes at the driver ant's nests suggested that chimpanzees used them as wands to dip for ants. the frequency of ant dipping and length of wands may ... | 2000 | 30545196 |
| functional parameters of chimpanzee (pan troglodytes) sperm from ejaculates collected by rectal probe electrostimulation and by artificial vagina. | this study compares functional parameters of sperm from ejaculates collected from 15 adult male chimpanzees using rectal probe electrostimulation (rpe) and from 10 adult male chimpanzees trained to use an artificial vagina (av). computer assisted motion analysis (cama) showed no significant differences in mean values for straight line velocity (vsl), linearity (lin), curvilinear velocity (vcl), and lateral head movement (alh) of sperm from ejaculates collected by rpe and by av. there was, howeve ... | 1996 | 31918494 |
| effect of liquefaction time on semen parameters in chimpanzee (pan troglodytes) ejaculates. | ejaculates were obtained from eight adult male chimpanzees trained to use an artificial vagina. spontaneously liquefied fractions were collected at 0-1, 1-2 and 2-4 h after ejaculation. the mean volumes of the spontaneously liquefied fractions did not differ significantly among the three fractions. the total number of sperm, the percentage of motile sperm and the percentage of live sperm decreased significantly (p < 0.005) between the 0-1 and 1-2 h fractions. citrate concentration and alpha-gluc ... | 1995 | 32005048 |
| model life table for captive chimpanzees. | mortality statistics from three captive populations of chimpanzees (pan troglodytes) were combined to generate standard model life tables for each sex in this species. the model is compared to an estimate of survivorship of a group of wild animals, and is applied to an incomplete data set to illustrate how the model may be used to extend estimates of mortality statistics to missing older ages. © 1995 wiley-liss, inc. | 1995 | 32005046 |
| relationship of chimpanzee leaf-swallowing to a tapeworm infection. | leaf-swallowing by chimpanzees pan troglodytes has been hypothesized to control parasites, but it has not yet been shown to be associated with specific parasitic infections. this report takes advantage of a tapeworm infestation among wild chimpanzees to examine whether leaf-swallowing was associated with the presence of tapeworms. leaf-swallowing was monitored over 6.5 years in two chimpanzee communities in kibale national park (uganda). in one community, tape-worms ?bertiella studeri were found ... | 1995 | 31936954 |
| drinking tools of wild chimpanzees at bossou. | use of drinking tools by wild chimpanzees (pan troglodytes) and the context in which the tools were used were studied at bossou, republic of guinea, west africa. during the middle to late dry season and early wet season liquids are available occasionally in the holes of trees. chimpanzees drank water or sap using a leaf (or fiber) as a sponge or spoon. when the chimpanzees were on the ground, they tended to use one of a few kinds of soft, hairless leaves, if they were available nearby. females, ... | 1995 | 31936951 |
| characteristics of chimpanzee (pan troglodytes) ejaculates collected by rectal probe electrostimulation and by artificial vagina. | this study compares characteristics of ejaculates collected from 16 adult male chimpanzees using rectal probe electrostimulation (rpe) and from 10 adult male chimpanzees trained to use an artificial vagina (av). ejaculate weight, semen volume, and sperm number were significantly lower (p < 0.01) and percentage liquefaction was significantly higher (p < 0.01) in ejaculates collected by rpe. percentages of motile sperm and of live sperm in semen did not differ significantly between the two collect ... | 1995 | 31924077 |
| sodium, potassium, and protein concentrations and 2d-sds-page of epididymal luminal and ejaculated seminal fluids of the adult chimpanzee (pan troglodytes). | the concentration of soluble protein and of sodium and potassium ions was estimated in chimpanzee caput epididymal luminal fluid, cauda epididymal luminal fluid, and ejaculated seminal fluid. protein concentration was 48.5 ± 1.5 μg/μl in caput fluid, 26.8 ± 2.0 μg/μl in cauda fluid, and 53.0 ± 7.9 μg/μl in seminal fluid. sodium concentration was 127.0 ± 7.0 mm in caput fluid, 34.5 ± 1.8 mm in cauda fluid, and 18.8 ± 1.8 mm in seminal fluid. potassium concentration was 58.0 ± 0.0 mm in caput flui ... | 1994 | 31936966 |
| semen characteristics of the adult male chimpanzee (pan troglodytes). | the chimpanzee, because of its similarities to the human, is especially valuable in studies of reproductive function. however, relatively little is known about the physiology of reproduction in the adult male chimpanzee. this study provides, for five adult male chimpanzees, baseline values for testicular volume without and with pressure and for cellular and biochemical characteristics of ejaculates collected by artificial vagina (av). there was no correlation between body weight and testicular v ... | 1993 | 31941187 |
| anogenital swelling in pregnant chimpanzees of gombe national park. | previous studies show that anogenital swelling patterns of pregnant chimpanzees in captivity are correlated with the female's age during pregnancy and are associated with changes in social behavior. the purpose of the present study was to investigate whether the anogenital swelling patterns of free-ranging pregnant chimpanzees resemble those reported for captive chimpanzees. we reviewed the records of 47 pregnancies experienced by 20 female chimpanzees living in gombe national park from 1975 to ... | 1993 | 31937004 |
| range use of the forest chimpanzees of kibale: implications for the understanding of chimpanzee social organization. | we contrast the range use patterns of male and female chimpanzees (pan troglodytes) based on repeated sightings over three years of 19 individuals in the kanyawara community of kibale forest reserve, uganda. depending on how home range size was calculated, male chimpanzees used an area that was 1.5 to 2 times greater than that of females. there was no difference between the sexes in whether their home ranges were used in a clumped or uniform fashion. however, males were more likely to be seen in ... | 1993 | 31936990 |
| male chimpanzee behavior in relation to female ano-genital swelling. | this study examined the relationships between male agonistic, affiliative, and sexual behaviors and female estrus condition in captive adolescent and young-adult chimpanzees (pan troglodytes). data on agonistic, affiliative, and sexual behaviors of 11 males living in three social groups were collected during daily 45 minute observations over a 5 month period. female estrus condition was assessed daily using the relative size of the female's ano-genital swelling. it was hypothesized that the pres ... | 1992 | 31948163 |
| abnormal behaviors, with a special focus on rocking, and reproductive competence in a large sample of captive chimpanzees (pan troglodytes). | chimpanzees (pan troglodytes) are endangered in the wild and may no longer be imported into the united states. of those animals presently in captivity, candidates for breeding programs must be identified to insure a self-sustaining captive population. some have suggested that poor reproductive performance might be linked to the performance of abnormal behaviors. in study 1, three institutions housing breeding colonies of chimpanzees (86 males, 103 females) surveyed their animals for abnormal beh ... | 1992 | 31948132 |
| chimpanzee genital swelling and its role in the pattern of sociosexual behavior. | behavioral observations were made on thirteen female and seven male adult group-living chimpanzees (pan troglodytes). the behavioral data were analyzed as a function of the day of the females' menstrual cycles to explore the possible interrelationship between genital swelling and sociosexual behavior of female chimpanzees. copulatory behavior was confined almost entirely to the period of genital swelling and the occurrence of male-to-female genital inspection (both female- and male-initiated) wa ... | 1992 | 31941218 |
| dna "fingerprinting" and the genetic management of a captive chimpanzee population (pan troglodytes). | dna fingerprinting probes are cloned sequences which simultaneously detect a large number of similar hypervariable loci in the target dna. the resulting highly polymorphic pattern visualized on an autoradiograph allows resolution of questions concerning individual identification and parentage. m13 bacteriophage has been used as a dna fingerprinting probe for paternity ascertainment among captive chimpanzees housed in multi-male groups as part of the national chimpanzee breeding and research prog ... | 1991 | 31952396 |
| national chimpanzee breeding program: primate research institute. | the primate research institute (pri) dedicated a colony of 81 proven breeders (60 females, 21 males) to the national chimpanzee breeding and research program (ncbrp). when possible, infants were left with their mothers for a minimum of 18 months. programs to define and reduce fetal wastage and neonatal mortality were implemented. pregnancies were diagnosed both by ria for serum chorionic gonadotropin and by ultrasound prior to day 30 of pregnancy. of 65 pregnancies detected by ultrasound and ria ... | 1991 | 31952388 |
| monitoring the ovarian cycles of pan troglodytes and p. paniscus: a comparative approach. | females of both species of chimpanzee, pan troglodytes and p. paniscus, exhibit conspicuous anogenital sex swellings that are useful external markers for assessing ovarian cyclicity. a new, quantitative method for describing these swelling cycles was refined during laboratory studies of four p. paniscus and nine p. troglodytes and was used to analyze variability in swelling patterns. clear-cut anatomical changes of the perineum were found to have both interindividual and interspecific reliabilit ... | 1991 | 31952385 |
| postpartum infertility in common chimpanzees. | the endocrine profile during normal postpartum amenorrhea in chimpanzees (pan troglodytes) closely resembles that of women, and its duration is similarly extended by nursing. however, when infant chimpanzees in our colony were removed at birth, excessively prolonged postpartum amenorrhea (7-26 months duration) occurred in 24% of cases. our endocrine studies indicate that such prolonged postpartum amenorrhea (ppam) is a pathological condition associated with chronically elevated serum prolactin l ... | 1991 | 31952381 |
| intestinal parasites of sympatric pan troglodytes and papio spp. at two sites: gombe (tanzania) and mt. assirik (senegal). | experimental and clinical parasitology need natural baselines or "controls". we present normative data intestinal parasite loads in two genera of african primates. wild pan troglodytes and papio spp. were studied at two sites: gombe in tanzania (p. anubis) and mt. assirik in senegal (p. papio). presence or absence of parasites, especially nematodes, was recorded from fecal specimens. gombe's primates were more often infected than were mt. assirik's. at gombe, but not at mt. assirik, chimpanzees ... | 1989 | 31968849 |
| uncertain availability of a preferred food affects choice in a captive group of chimpanzees (pan troglodytes). | food-choice was investigated in a social group of 16 chimpanzees (pan troglodytes) maintained in a large outdoor compound. three feeding stations located along the periphery of the compound were considered analogous to food patches. color-coded aluminum panels temporarily covered each feeding apparatus, with one color corresponding to nonpreferred food (commercial biscuits) available at two locations and other colors corresponding to the certain or uncertain availability of preferred food (orang ... | 1989 | 31968847 |
| features of meat digestion by captive chimpanzees (pan troglodytes). | the pronounced carnivory of many human populations contrasts sharply with feeding habits of other hominoidea. of extant great apes, only chimpanzees (pan spp.) actively seek out vertebrate prey, but meat is only a minor portion of their diet. some accounts suggest that wild chimpanzees digest prey inefficiently. to investigate the capacity of chimpanzees to digest meat, feeding trials were carried out on three captive chimpanzees (pan troglodytes) using a fixed amount of nonpurified diet with an ... | 1989 | 31964047 |
| improved methods for freeze preservation of chimpanzee sperm. | freeze preservation of human and nonhuman semen has been used effectively for a number of years; however, the application of freezing to preserve nonhuman primate sperm has been less successful. this study compares five freeze methods and various concentrations of the cryoprotectants glycerol and dimethylsulfoxide (dmso) for cryopreservation of chimpanzee (pan troglodytes) sperm. the different methods were compared using quantitative analysis of sperm function and, by an indirect measure of fert ... | 1989 | 31964027 |
| long-term retention of self-recognition by chimpanzees. | two young chimpanzees showed retention of self-recognition after 1 year without access to mirrors. a year earlier the animals were positive on the gallup dye test. one year later they were once again anesthetized, marked on the brow and ears, and following recovery, exposed individually to a large mirror. both demonstrated mirror-orientated mark-directed responses. time-sample observations of behavior toward the mirror further support self-recognition. the chimpanzee's self-awareness, as inferre ... | 1988 | 31968884 |
| social factors influencing choice of food source in a captive group of chimpanzees (pan troglodytes). | the influence of social factors, including social relationship, kinship, estrous cycle stage and hierarchical rank, on choice of a food source was studied in a group of 16 chimpanzees (pan troglodytes) maintained in a large, outdoor compound. the subjects chose among three feeding stations that were spatially separated and located along the periphery of the compound. one feeding station was associated with a preferred food (orange), and two stations contained a less-preferred food (commercial ch ... | 1988 | 31968878 |
| diet of wild chimpanzees (pan troglodytes verus) at mt. assirik, senegal: i. composition. | the composition of the diet of a savanna-living population of wild chimpanzees (pan troglodytes verus) at mt. assirik in senegal is presented. the study site had a prolonged dry season, high temperatures, and vegetation dominated by grasses. data came from direct observation, fecal specimens, and feeding traces; thus, strict criteria for acceptance of the indirect data were specified. composition of diet was given in terms of species and family of prey, parts eaten, life-form, type of habitat, a ... | 1988 | 31968861 |
| focal epithelial hyperplasia of the oral mucosa in two chimpanzees (pan troglodytes). | papillomas in the oral mucosa compatible with focal epithelial hyperplasia are reported in two chimpanzees. the lesions were studied by light and electron microscopy. virus particles were not observed. the literature dealing with focal epithelial hyperplasia in humans and other animals is reviewed. | 1986 | 31979497 |
| ontogeny of mirror behavior in two species of great apes. | mirror image reactions of two infant apes, a female chimpanzee (pan troglodytes) and a male orangutan (pongo pygmaeus), born at the zoo de vincennes and the jardin des plantes of paris, france, respectively, were studied and compared with those of children. self-recognition was also tested following 46.5 hours of mirror exposure by application of red marks on parts of the body invisible to the animal without the aid of the mirror. results indicated that the behavior of the two young apes followe ... | 1986 | 31979488 |
| social behavior and genital swelling in pregnant chimpanzees (pan troglodytes). | previous reports of increased sexual activity associated with genital swelling during chimpanzee pregnancy have suggested that the tumescent pregnant female may be regarded as a regularly cycling estrous female. analysis of additional data from seven pregnant and eight cycling females, however, indicated that tumescent pregnant females differed from cycling females in some social interactions with males. as in earlier reports, pregnant females were more receptive to male-initiated copulatory bou ... | 1986 | 31979487 |
| hand preference in a captive island group of chimpanzees (pan troglodytes). | morphological cerebral asymmetries in chimpanzee brains, similar to those found in humans, in whom they are associated with speech and handedness, suggest the possibility of functional lateralization in the chimpanzee. this possibility was investigated by examining hand preferences in an island group of five chimpanzees on a series of unimanual and bimanual tasks that are diagnostic of human hand and cerebral dominance. each subject was tested in a double compartment cage on three unimanual nons ... | 1986 | 31979471 |
| effect of solar eclipse on the behavior of a captive group of chimpanzees (pan troglodytes). | a captive group of chimpanzees, housed in an outdoor compound at the yerkes regional primate research center, was observed during the annular solar eclipse of may 30, 1984. the behavior of each animal was recorded using an instantaneous scan-sampling technique (altmann: behaviour 49:227-265, 1974). beginning 2 days prior to the eclipse and continuing through the day following the eclipse, data were collected from 1100 to 1300 hours daily. at 1214 hours on the day of the eclipse, when the sky beg ... | 1986 | 31979439 |
| tool use by wild chimpanzees (pan troglodytes) to obtain termites (macrotermes herus) in the mahale mountains, tanzania. | wild chimpanzees (pan troglodytes) used probes made of vegetation to fish for termites (macrotermes herus) in the mahale mountains of western tanzania. data on both the artefacts and behavior associated with their use were recorded over a 5-month period. the chimpanzees of one unit group, b group, were seen four times to use the tools to extract the insects from their mounds. a sample of 290 tools was collected and analyzed in terms of age, seasonality, length, width, class of raw materials, spe ... | 1985 | 31986794 |
| serum levels of gonadotropins and gonadal steroids, including testosterone, during the menstrual cycle of the chimpanzee (pan troglodytes). | the objective of this study was to expand the data on menstrual cycle serum hormone patterns in female common chimpanzees, both in terms of the number of cycles analyzed and by the addition of data on testosterone levels. samples were obtained from 11 unanesthetized animals trained for conscious blood withdrawal. lh, fsh, 17β-estradiol (e2), progesterone (p), and testosterone (t) were measured by radioimmunoassay, genital swelling was recorded, and menstrual blood was noted. concurrent midcycle ... | 1985 | 31979509 |
| the effect of peer separation in young chimpanzees (pan troglodytes). | ten chimpanzees (pan troglogytes), aged 18-24 months, housed without mothers as two dyads and two triads, were subjected to social separation. two issues were addressed: the effects of peer separation in chimpanzees; and differential responses by subjects living in dyads compared with those living in triads. chimpanzees that were alone during separation reacted with high levels of "protest" alternating with "despair" throughout the separation period. the continued presence of one cagemate, durin ... | 1983 | 31992011 |
| brief report: chimpanzees, tools, and termites: new record from gabon. | wild chimpanzees (pan troglodytes) in northeastern gabon use tools made of vegetation to obtain termites (macrotermes? nobilis) for food. they mostly use probes in termite fishing, as recorded elsewhere in eastern and far western africa. this is the first record of termite fishing by the central west african race of chimpanzees. there are signs that they also use stouter tools, perhaps to perforate the mounds of the termites. these new findings further complicate the status of material culture i ... | 1983 | 31991943 |
| brief report: differential oxidations of estradiol-17β by the chimpanzee in vivo. | the metabolism of estradiol-17β is primarily an oxidative process at either carbon-2 or carbon-16 in the human. the objective of this study was to determine the relative importance of these two oxygenation pathways in the chimpanzee. the rate of oxidation of estradiol-17β at each position was determined by measuring the release of tritium into body water from carbon-2 or carbon-16. [2-3h]-estradiol-17β or [16-3h]-estradiol-17β was injected intravenously into three adult male chimpanzees, and blo ... | 1983 | 31986865 |
| sexual behavior of captive chimpanzees (pan troglodytes): pregnant versus cycling females. | sexual behavior was observed in fifteen female and seven male captive adult chimpanzees over a period of three months. relative frequencies of successful and unsuccessful copulatory attempts were compared to levels of anogenital swelling and reproductive status. in addition, the data were analyzed in relation to three indicators of female primate sexuality: (1) proceptivity, indicated by female attempts at sexual interaction; (2) attractivity, indicated by male-initiated attempts; and (3) recept ... | 1982 | 31992001 |
| biochemical detection of fecal hematin as a test for meat eating in chimpanzees (pan troglodytes). | meat-eating by wild chimpanzees has been reported by a number of workers during the last two decades. direct observation probably underestimates the incidence, even though the behavior occurs relatively infrequently. in 1978, moreno-black suggested that fecal analysis over a long period of time is probably the most effective means to determine the incidence of this behavior in wild chimpanzees and other nonhuman primate groups. a method currently employed by a number of fieldworkers involves the ... | 1982 | 31991988 |
| a descriptive study of zoonotic disease risk at the human-wildlife interface in a biodiversity hot spot in south western uganda. | zoonotic diseases pose a significant health challenge at the human-wildlife interface, especially in sub-saharan africa where ecosystem services contribute significantly to local livelihoods and individual well-being. in uganda, the fragmented forests of hoima district, form part of a biodiversity and emerging infectious disease hotspot composed of communities with high dependency on these wildlife protected areas, unaware of the associated health risks. we conducted a cross-sectional mixed meth ... | 2021 | 33406074 |
| research and conservation in the greater gombe ecosystem: challenges and opportunities. | the study of chimpanzees in gombe national park, tanzania, started by jane goodall in 1960, provided pioneering accounts of chimpanzee behavior and ecology. with funding from multiple sources, including the jane goodall institute (jgi) and grants from private foundations and federal programs, the project has continued for sixty years, providing a wealth of information about our evolutionary cousins. these chimpanzees face two main challenges to their survival: infectious disease - including simi ... | 2020 | 33343005 |