| genomic analyses of bifidobacterium moukalabense reveal adaptations to frugivore/folivore feeding behavior. | despite the essential role of bifidobacterium in health-promoting gut bacteria in humans, little is known about their functions in wild animals, especially non-human primates. it is difficult to determine in vivo the function of bifidobacterium in wild animals due to the limited accessibility of studying target animals in natural conditions. however, the genomic characteristics of bifidobacterium obtained from the feces of wild animals can provide insight into their functionality in the gut. her ... | 2019 | 30987363 |
| from groups to communities in western lowland gorillas. | social networks are the result of interactions between individuals at different temporal scales. thus, sporadic intergroup encounters and individual forays play a central role in defining the dynamics of populations in social species. we assessed the rate of intergroup encounters for three western lowland gorilla ( gorilla gorilla gorilla) groups with daily observations over 5 years, and non-invasively genotyped a larger population over four months. both approaches revealed a social system much ... | 2019 | 30963928 |
| diagnosing cardiovascular disease in western lowland gorillas (gorilla gorilla gorilla) with brain natriuretic peptide. | cardiovascular disease is a leading cause of death in zoo-housed great apes, accounting for 41% of adult gorilla death in north american zoological institutions. obtaining a timely and accurate diagnosis of cardiovascular disease in gorillas is challenging, relying on echocardiography which generally requires anesthetic medications that may confound findings and can cause severe side effects in cardiovascularly compromised animals. the measurement of brain natriuretic peptide (bnp) has emerged a ... | 2019 | 30889217 |
| novelty response of wild african apes to camera traps. | temperament and personality research in humans and nonhuman animals measures behavioral variation in individual, population, or species-specific traits with implications for survival and fitness, such as social status, foraging, and mating success [1-5]. curiosity and risk-taking tendencies have been studied extensively across taxa by measuring boldness and exploration responses to experimental novelty exposure [3, 4, 6-15]. here, we conduct a natural field experiment using wildlife monitoring t ... | 2019 | 30880013 |
| index hopping on the illumina hiseqx platform and its consequences for ancient dna studies. | the high-throughput capacities of the illumina sequencing platforms and the possibility to label samples individually have encouraged wide use of sample multiplexing. however, this practice results in read misassignment (usually <1%) across samples sequenced on the same lane. alarmingly high rates of read misassignment of up to 10% were reported for lllumina sequencing machines with exclusion amplification chemistry. this may make use of these platforms prohibitive, particularly in studies that ... | 2019 | 30848092 |
| hominoid anterior teeth from the late oligocene site of losodok, kenya. | kamoyapithecus hamiltoni is a potential early hominoid species described from fragmentary dentognathic specimens from the oligocene site of losodok (turkana basin, northwestern kenya). other catarrhine dental materials have been recovered at losodok, but were not initially included in the kamoyapithecus hypodigm. here we present descriptions of the unpublished canine and incisor specimens from losodok, and revisit the published specimens in light of recent changes in understanding of hominoid an ... | 2019 | 30825982 |
| foraging in a social setting: a comparative analysis of captive gorillas and chimpanzees. | this study was designed to investigate the foraging behavior of zoo-housed western lowland gorillas (gorilla gorilla gorilla) and compare it with that of zoo-housed chimpanzees (pan trogloydytes) tested previously in a similar paradigm. specifically, we aimed to document how a group of zoo-housed gorillas foraged within a familiar environment to discover novel food sources and whether they sought out more preferred foods, even if they had to travel further to reach them, as they do in the wild. ... | 2019 | 30806863 |
| trabecular architecture of the great ape and human femoral head. | studies of femoral trabecular structure have shown that the orientation and volume of bone are associated with variation in loading and could be informative about individual joint positioning during locomotion. in this study, we analyse for the first time trabecular bone patterns throughout the femoral head using a whole-epiphysis approach to investigate how potential trabecular variation in humans and great apes relates to differences in locomotor modes. trabecular architecture was analysed usi ... | 2019 | 30793309 |
| hardly habitual: chimpanzees and gorillas show flexibility in their motor responses when presented with a causally-clear task. | in contrast to reports of wild primates, studies of captive primates' flexibility often reveal conservatism: individuals are unable to switch to new and more efficient strategies when task demands change. we propose that such conservatism might be a result of task design and hypothesize that conservatism might be linked to primates' lack of causal understanding in relation to experimental apparatuses. we investigated if chimpanzees (pan troglodytes) and western lowland gorillas (gorilla gorilla ... | 2019 | 30643700 |
| humeral anatomy of the knm-er 47000 upper limb skeleton from ileret, kenya: implications for taxonomic identification. | knm-er 47000 is a fossil hominin upper limb skeleton from the koobi fora formation, kenya (fwjj14e, area 1a) that includes portions of the scapula, humerus, ulna, and hand. dated to ∼1.52 ma, the skeleton could potentially belong to one of multiple hominin species that have been documented in the turkana basin during this time, including homo habilis, homo erectus, and paranthropus boisei. although the skeleton lacks associated craniodental material, the partial humerus (described here) preserve ... | 2019 | 30583842 |
| noninvasive western lowland gorilla's health monitoring: a decade of simian immunodeficiency virus surveillance in southern cameroon. | simian immunodeficiency virus (sivgor) causes persistent infection in critically endangered western lowland gorillas (gorilla gorilla gorilla) from west central africa. sivgor is closely related to chimpanzee and human immunodeficiency viruses (sivcpz and hiv-1, respectively). we established a noninvasive method that does not interfere with gorillas' natural behaviour to provide wildlife pathogen surveillance and health monitoring for conservation. a total of 1,665 geo-referenced fecal samples w ... | 2018 | 30519399 |
| recycling 115,369 mobile phones for gorilla conservation over a six-year period (2009-2014) at zoos victoria: a case study of 'points of influence' and mobile phone donations. | more than seven billion mobile phones are estimated to be in service globally, with more than a billion older phones likely to be retired. a major barrier to a sustainable circular economy for mobile phones is people's hoarding of their retired phones. old mobile phones may be refurbished for re-use or ultimately dismantled for possible extraction of elements, including 'conflict' metals such as coltan (containing elements tantalum and niobium), mined in eastern democratic republic of congo and ... | 2018 | 30517131 |
| behavioral changes following alterations in the composition of a captive bachelor group of western lowland gorillas (gorilla gorilla gorilla). | western lowland gorillas (gorilla gorilla gorilla) in zoos are housed in family or bachelor groups to maximize social opportunities. while wild bachelor groups are transient, all-male groups in zoos may be maintained for many years. captive bachelor groups need to be carefully monitored, particularly during periods of demographic transition, due to the possibility for escalating aggression. we examined behavioral changes in a bachelor group at the saint louis zoo following two significant altera ... | 2018 | 30371940 |
| variation in the social organization of gorillas: life history and socioecological perspectives. | a focus of socioecological research is to understand how ecological, social, and life history factors influence the variability of social organization within and between species. the genus gorilla exhibits variability in social organization with western gorilla groups being almost exclusively one-male, yet approximately 40% of mountain gorilla groups are multimale. we review five ultimate causes for the variability in social organization within and among gorilla populations: human disturbance, e ... | 2018 | 30325554 |
| an unexpected diversity of trypanosomatids in fecal samples of great apes. | charismatic great apes have been used widely and effectively as flagship species in conservation campaigns for decades. these iconic representatives of their ecosystems could also play a role as reservoirs of several zoonotic diseases. recently it was demonstrated that african great apes can host leishmania parasites (kinetoplastea: trypanosomatidae). given that this finding raised a strong negative reaction from leishmania experts and the subsequent discussion did not lead to a clear resolution ... | 2018 | 30225193 |
| long bone diaphyseal shape follows different ontogenetic trajectories in captive and wild gorillas. | a number of studies have demonstrated the ontogenetic plasticity of long bone diaphyseal structure in response to mechanical loading. captivity should affect mechanical loading of the limbs, but whether captive apes grow differently than wild apes has been debated. here, we compare captive and wild juvenile and adult gorilla to ascertain whether growth trajectories in cross-sectional diaphyseal shape are similar in the two environments. | 2018 | 30159891 |
| characteristics of gorilla-specific lactobacillus isolated from captive and wild gorillas. | lactic acid bacteria (lab) reside in a wide range of mammals, such as autochthonous intestinal bacteria. in this paper, we present the phenotypic and phylogenetic characteristics of gorilla-specific lab. lactobacillus gorillae-previously isolated from the wild and captive western lowland gorillas (gorilla gorilla gorilla)-were successfully isolated from wild mountain gorillas (gorilla gorilla beringei) in addition to other captive and wild western lowland gorillas. the strains from wild gorillas ... | 2018 | 30110987 |
| validating the use of a commercial enzyme immunoassay to measure oxytocin in unextracted urine and saliva of the western lowland gorilla (gorilla gorilla gorilla). | the neuroendocrine hormone oxytocin, which is an important physiological driver of social behavior and bonding, is increasingly being measured in conjunction with behavior to better understand primate sociality. to date no data are available on oxytocin concentrations within the genus gorilla; however, as a result of their close genetic relatedness to humans, and tolerance-based social system, gorilla represents an important group of study. the purpose of this study was to validate the measureme ... | 2018 | 30030689 |
| why human environments enhance animal capacities to use objects: evidence from keas (nestor notabilis) and apes (gorilla gorilla, pan paniscus, pongo abelii, pongo pygmaeus). | formal training programs, which can be called education, enhance cognition in human and nonhuman animals alike. however, even informal exposure to human contact in human environments can enhance cognition. we review selected literature to compare animals' behavior with objects among keas and great apes, the taxa that best allow systematic comparison of the behavior of wild animals with that of those in human environments such as homes, zoos, and rehabilitation centers. in all cases, we find that ... | 2018 | 30024236 |
| long-term group membership and dynamics in a wild western lowland gorilla population (gorilla gorilla gorilla) inferred using non-invasive genetics. | the social organization of a group-living animal is defined by a balance between group dynamic events such as group formation, group dissolution, and dispersal events and group stability in membership and over time. understanding these processes, which are relevant for questions ranging from disease transmission patterns to the evolution of polygyny, requires long-term monitoring of multiple social units over time. because all great ape species are long-lived and elusive, the number of studies o ... | 2018 | 30024040 |
| empirical selection between least-cost and current-flow designs for establishing wildlife corridors in gabon. | corridors are intended to increase species survival by abating landscape fragmentation resulting from the conversion of natural habitats into human-dominated matrices. conservation scientists often rely on 1 type of corridor model, typically the least-cost model or current-flow model, to construct a linkage design, and their choice is not usually based on theory or empirical evidence. we developed a method to empirically confirm whether corridors produced by these 2 models are used by target spe ... | 2019 | 30022531 |
| trabecular bone patterning in the hominoid distal femur. | in addition to external bone shape and cortical bone thickness and distribution, the distribution and orientation of internal trabecular bone across individuals and species has yielded important functional information on how bone adapts in response to load. in particular, trabecular bone analysis has played a key role in studies of human and nonhuman primate locomotion and has shown that species with different locomotor repertoires display distinct trabecular architecture in various regions of t ... | 2018 | 30002981 |
| management of respiratory complications in a western lowland gorilla (gorilla gorilla gorilla) born by cesarean section. | a female western lowland gorilla (gorilla gorilla gorilla) infant was delivered by cesarean section (c-section) to an 18-year-old primiparous dam after prolonged labor. the infant required resuscitation at birth and was hospitalized for management of pneumonia and associated respiratory distress secondary to the aspiration of meconium-stained amniotic fluid. the infant received nine days of intensive care with respiratory support, antibiotics, intravenous fluid therapy, anti-inflammatory drugs, ... | 2018 | 29974496 |
| trajectory analysis among african hominoids can provide insights into genetic and epigenetic influences during ontogeny. | prior examination of the ontogeny of hominoid talo-crural joint morphology using singular warp analysis suggested both a genetic and epigenetic signal during development. this question is examined using trajectory analysis and its implications for the hominin fossil record explored. | 2018 | 29968909 |
| visceral leishmaniasis in an infant gorilla (gorilla gorilla gorilla): clinical signs, diagnosis, and successful treatment with single-dose liposomal amphotericin b. | a 2-year-old captive gorilla (gorilla gorilla gorilla) was diagnosed with visceral leishmaniasis in brazil, and treated with a single dose of liposomal amphotericin b, which resulted in clinical cure. this is the first report of visceral leishmaniasis in gorillas, and the first reported liposomal amphotericin b treatment in great apes. | 2018 | 29956831 |
| comparing the sniffing behavior of great apes. | the importance of smell in humans is well established but we know little about it in regard to our closest relatives, the great apes, as systematic studies on their olfactory behavior are still lacking. olfaction has long been considered to be of lesser importance in hominids given their relatively smaller olfactory bulbs, fewer functional olfactory receptor genes than other species and absence of a functional vomeronasal organ. therefore, the aim of this study was to evaluate the use of olfacti ... | 2018 | 29756687 |
| stillbirth rates across three ape species in accredited american zoos. | stillbirths, or births of infants that died in the womb, represent a failure of the materno-feto-placental unit to maintain a suitable fetal environment. typical studies of nonhuman primate (nhp) stillbirth patterns are primarily descriptive and focus on macaques (genus macaca). thus, less is known about other nhp species and rarer still are studies that examine possible biological factors that influence stillbirth rates across taxa. to examine possible contributors to stillbirths in great apes, ... | 2018 | 29756650 |
| the first multi-zoo application of an allostatic load index to western lowland gorillas (gorilla gorilla gorilla). | vertebrate stress responses are highly adaptive biological functions, maximizing survival probability in life-threatening situations. however, experiencing repeated and/or chronic stressors can generate physiological dysregulation and lead to disease. because stress responses are multi-systemic and involve a wide range of physiological functions, identifying responses to stressors is best accomplished using integrated biomarker models. allostatic load, defined as the physiological dysregulation ... | 2018 | 29746855 |
| spatial representation of magnitude in humans (homo sapiens), western lowland gorillas (gorilla gorilla gorilla), and american black bears (ursus americanus). | the spatial-numerical association of response codes (snarc) effect is the tendency for humans to respond faster to relatively larger numbers on the left or right (or with the left or right hand) and faster to relatively smaller numbers on the other side. this effect seems to occur due to a spatial representation of magnitude either in occurrence with a number line (wherein participants respond to relatively larger numbers faster on the right), other representations such as clock faces (responses ... | 2018 | 29728786 |
| the interplay of prior experience and motivation in great ape problem-solving (gorilla gorilla, pan paniscus, pan troglodytes, and pongo abelii). | many primate species have a strong disposition to approach and manipulate objects in captivity. however, few studies have investigated what primates learn during free exploration of objects in the absence of rewards, and how previous problem-solving performance influences subsequent exploration. we confronted members of each of the four nonhuman great ape species (n = 25) with the collapsible platform task that required subjects to drop a stone inside a tube to collapse a platform and release a ... | 2018 | 29708360 |
| guns, germs, and trees determine density and distribution of gorillas and chimpanzees in western equatorial africa. | we present a range-wide assessment of sympatric western lowland gorillas gorilla gorilla gorilla and central chimpanzees pan troglodytes troglodytes using the largest survey data set ever assembled for these taxa: 59 sites in five countries surveyed between 2003 and 2013, totaling 61,000 person-days of fieldwork. we used spatial modeling to investigate major drivers of great ape distribution and population trends. we predicted density across each taxon's geographic range, allowing us to estimate ... | 2018 | 29707637 |
| dialium seed coprophagy in wild western gorillas: multiple nutritional benefits and toxicity reduction hypotheses. | unraveling the relationship between the unusual feeding behaviors and the nutritional intake of endangered species may provide crucial information for understanding species response to habitat unpredictable changes. primates occasionally re-ingest fruit seeds alongside ingestion of feces, a behavior called coprophagy. the nutritional benefit is one of the several non-mutual exclusive hypotheses proposed to explain this behavior. we investigated the ecological correlates of coprophagy in wild wes ... | 2018 | 29664132 |
| differences in play can illuminate differences in affiliation: a comparative study on chimpanzees and gorillas. | play behaviour reinforces social affiliation in several primate species, including humans. via a comparative approach, we tested the hypothesis that play dynamics in a group of lowland gorillas (gorilla gorilla gorilla) are different from those in a group of chimpanzees (pan troglodytes) as a reflection of their difference in social affiliation and agonistic support. we selected one group of lowland gorillas and one of chimpanzees, hosted at the zooparc de beauval (france), managed in a similar ... | 2018 | 29513696 |
| expression of concern: biologically validating the measurement of oxytocin in western lowland gorilla (gorilla gorilla gorilla) urine and saliva using a commercial enzyme immunoassay. | | 2018 | 29502326 |
| great ape walking kinematics: implications for hominoid evolution. | great apes provide a point of reference for understanding the evolution of locomotion in hominoids and early hominins. we assessed (1) the extent to which great apes use diagonal sequence, diagonal couplet gaits, like other primates, (2) the extent to which gait and posture vary across great apes, and (3) the role of body mass and limb proportions on ape quadrupedal kinematics. | 2018 | 29313896 |
| population-level assessment of genetic diversity and habitat fragmentation in critically endangered grauer's gorillas. | the critically endangered grauer's gorilla (gorilla beringei graueri) has experienced an estimated 77% population decline within a single generation. although crucial for informed conservation decisions, there is no clear understanding about population structure and distribution of genetic diversity across the species' highly fragmented range. we fill this gap by studying several core and peripheral grauer's gorilla populations throughout their distribution range. | 2018 | 29313894 |
| body signals used during social play in captive immature western lowland gorillas. | the play face is a well-established play signal in nonhuman primates that functions to invite play and convey a playful intent. however, recent evidence indicates that some species display repertoires of play signals that may have more specific meanings related to particular aspects of play. furthermore, previous studies have inconsistently categorized gorilla behaviors as play signals versus actual play. here we aim to identify behaviors displayed by two immature captive western lowland gorilla ... | 2018 | 29280023 |
| impact of stress on the gut microbiome of free-ranging western lowland gorillas. | exposure to stressors can negatively impact the mammalian gastrointestinal microbiome (gim). here, we used 454 pyrosequencing of 16s rrna bacterial gene amplicons to evaluate the impact of physiological stress, as evidenced by faecal glucocorticoid metabolites (fgcm; ng/g), on the gim composition of free-ranging western lowland gorillas (gorilla gorilla gorilla). although we found no relationship between gim alpha diversity (h) and fgcm levels, we observed a significant relationship between the ... | 2018 | 29205130 |
| food cleaning in gorillas: social learning is a possibility but not a necessity. | food cleaning is widespread in the animal kingdom, and a recent report confirmed that (amongst other behaviours) wild western lowland gorillas also show food cleaning. the authors of this report conclude that this behaviour, based on its distribution patterns, constitutes a potential candidate for culture. while different conceptualisations of culture exist, some more and some less reliant on behavioural form copying, all of them assign a special role to social learning processes in explaining p ... | 2017 | 29200437 |
| extant ape dental topography and its implications for reconstructing the emergence of early homo. | dental topography reflects diet accurately in several extant and extinct mammalian clades. however, dental topographic dietary reconstructions have high success rates only when closely related taxa are compared. given the dietary breadth that exists among extant apes and likely existed among fossil hominins, dental topographic values from many species and subspecies of great apes are necessary for making dietary inferences about the hominin fossil record. here, we present the results of one metr ... | 2017 | 29037413 |
| healed mid-shaft fracture of an early roman bovine femur. | we evaluated a healed fracture that was observed in the shaft of a bovine femur from an early roman settlement context at the site of wange, belgium. using external observation and x-ray images, the specimen is described, paying particular attention to displacement of the bone ends, shortening of the bone, and callus formation. similar fractures seen in femora of a modern derby's antelope (taurotragus derbianus) and of a modern eastern lowland gorilla (gorilla gorilla graueri) are described, and ... | 2015 | 29539477 |
| skeletal evidence of probable treponemal infection in free-ranging african apes. | the prevalence and patterning of inflammatory lesions of the skeleton were investigated in samples of chimpanzees (pan troglodytes troglodytes) and gorillas (gorilla gorilla gorilla) curated at the powell-cotton museum, birchington, uk. one hundred and two chimpanzees (42 adults and 60 subadults) and 126 gorillas (50 adults and 76 subadults) comprise the samples. twenty per cent of chimpanzees and 14% of gorillas were affected with a disseminated inflammatory skeletal condition caused by infecti ... | 2000 | 30545179 |
| spatial memory and foraging competition in captive western lowland gorillas (gorilla gorilla gorilla). | spatial memory and foraging competition were investigated in three mother/offspring pairs of western lowland gorillas,gorilla gorilla gorilla, using a naturalistic foraging task at the toronto zoo. sixteen permanent food sites were placed throughout the animals' enclosures. all of the sites were baited and a pair of animals was free to visit the sites and collect the food. five of the subjects collected the food with accuracy better than chance. most of the subjects visited the sites using a pat ... | 2000 | 30545167 |
| gorillas of bwindi-impenetrable forest and the virunga volcanoes: taxonomic implications of morphological and ecological differences. | based on their geographic proximity to the virunga volcanoes (≈ 25 km), the bwindi-impenetrable forest gorillas have been referred to the subspecies gorilla gorilla beringei. differences in anatomy, habitat, ecology, and behavior, however, suggest bwindi gorillas are distinct from those in the virungas. relative to virunga gorillas, bwindi gorillas live at lower elevations, in warmer temperatures, are much more arboreal, have longer day ranges and larger home ranges, and eat much more fruit and ... | 1996 | 31918511 |
| the acoustic features of gorilla double grunts and their relation to behavior. | mountain gorillas (gorilla gorilla beringei) give double-grunts to one another in a variety of situations, when feeding, resting, moving, or engaged in other kinds of social behavior. some double-grunts elicit double-grunts in reply whereas others do not. double-grunts are individually distinctive, and high-ranking animals give double-grunts at higher rates than others. there was no evidence, however, that the probability of eliciting a reply depended upon either the animals' behavior at the tim ... | 1994 | 31936924 |
| inter-group encounters and female transfer in mountain gorillas: influence of group composition on male behavior. | this paper examines the behaviors used by male gorillas (g. gorilla beringei) to influence female choice during inter-group encounters. encounters are related to the acquisition of females rather than to the defense of a group's range. data on 58 independent encounters confirms that encounters are generally aggressive, but that contact aggression is less frequent than previously reported. a high number of potential migrants in one of the groups involved, rather than the newness of either group, ... | 1993 | 31941180 |
| nonsocial behavior of captive infant gorillas. | frequencies of eight nonsocial behaviors (object contact, environmental exploration, mouthing, self-directed behavior, display behavior, solitary behavior, rest, and locomotion) were obtained for 20 infant lowland gorillas (gorilla gorilla gorilla) between 14 and 36 months of age. they lived in 13 groups in 10 zoological collections. approximately 12 hours of one-zero data were collected on each animal. behavioral data were analyzed with regard to the following independent variables: rearing his ... | 1992 | 31948168 |
| insect-eating by sympatric lowland gorillas (gorilla g. gorilla) and chimpanzees (pan t. troglodytes) in the lopé reserve, gabon. | sympatric populations of lowland gorillas (gorilla gorilla gorilla) and chimpanzees (pan troglodytes troglodytes) in the lopé reserve in central gabon consumed insects at similar average frequencies over a 7-year period (30% versus 31% feces contained insect remains). data came mostly from fecal analysis supplemented by observation and trail evidence. the weaver ant (oecophylla longinoda) was the species eaten most frequently by both gorillas and chimpanzees. other species of insects wore eaten ... | 1992 | 31941221 |
| composition of the diet of lowland gorillas at lopé in gabon. | this report describes the composition of the diet of lowland gorillas, gorilla gorilla gorilla, at lopé in central gabon. this population inhabits mature evergreen tropical forest and is not habituated to human observers. data were collected during 6 years of an ongoing long-term study, from feeding-trails and by direct observation, but mostly by fecal analysis. gorillas ate 182 plant foods from 134 species and 36 families. the fruit diet was diverse: 95 species were consumed, most with succulen ... | 1990 | 31963968 |
| pronucleus formation following in vitro fertilization of oocytes recovered from a gorilla (gorilla gorilla gorilla) with unilateral endometrioid adenocarcinoma of the ovary. | a 33-year-old, nonreproductive female gorilla was scheduled for ovariohysterectomy after diagnosing endometrioid adenocarcinoma of the right ovary; the contralateral ovary appeared small and inactive. follicular recruitment and maturation were stimulated on the left ovary using human menopausal gonadotropin and human chorionic gonadotropin therapy. three oocytes were recovered and inseminated using a thawed epididymal semen sample collected postmortem and cryopreserved. at 18 h postinsemination, ... | 1989 | 31964037 |
| environmental influences on mountain gorilla time budgets. | data on the time budgets of mountain gorillas (gorilla gorilla beringei) were collected during field studies in the virunga volcanoes region of rwanda and zaire. focal sampling was used to determine the proportion of time that individuals of different age/sex classes spent in several mutually exclusive activity states. the gorillas spent the majority of daylight hours feeding; most of the rest of the day was devoted to resting, with little time spent moving or engaged in social activity. the tim ... | 1988 | 31968891 |
| direct measurements of urinary estrone conjugates during the normal menstrual cycle of the gorilla (gorilla gorilla). | a direct immunoassay for urinary estrone conjugates (estrone sulfate and estrone glucuronide) was used to assess the preovulatory estrogen rise in normal gorilla menstrual cycles. immunoreactive estrone conjugates in samples concomitantly assessed for total estrogen immunoreactivity reflected similar profiles throughout the cycle; however, the speed and resolution of the direct assay for conjugates indicate this method to be more accurate in monitoring ovulation than the measurement of total imm ... | 1987 | 31973504 |
| physical and activity changes associated with pregnancy in captive lowland gorillas (gorilla gorilla gorilla). | the physical appearance and the behavior of five lowland gorilla females at two zoos were recorded before and during 14 pregnancies. whereas only the quality of changes associated with pregnancy had been described previously, in this study the behavior of the females was recorded quantitatively and evaluated statistically. all females at stuttgart showed distention of the abdomen three to four months before delivery and development of the breasts a few weeks before parturition. milk was produced ... | 1986 | 31979456 |
| observations on the ontogeny of feeding behavior in mountain gorillas (gorilla gorilla beringei). | this report describes observations on the ontogeny of food choice in mountain gorillas (gorilla gorilla beringei), made during a 17-month field study of mountain gorilla feeding ecology in the parc national des volcans, rwanda. data are presented on the feeding behavior of two infants observed from birth to the age of 8 months and on older infants and juveniles. this information is compared with data on the composition and diversity of the diets of young adults and adults in the same social grou ... | 1985 | 31986827 |
| improved method for artificial insemination in the great apes. | artificial insemination in the great apes has not achieved its potential as a tool in maintenance of the endangered captive population. three factors can influence the success rate of artificial insemination: sperm preparation, site of insemination, and timing of insemination. we have tried to optimize methods regarding these three steps. a modified method for insemination is described which has resulted in a 21% success rate (six term pregnancies from 29 inseminations) in the chimpanzee and whi ... | 1985 | 31986826 |
| nationwide census of gorilla (gorilla g. gorilla) and chimpanzee (pan t. troglodytes) populations in gabon. | a census was made of gorilla and chimpanzee populations throughout gabon between december 1980 and february 1983. the aim of the census was to estimate the total numbers of both species and describe their distributions. the method was based on nest counts from line transects which allowed the calculation of population densities of all individuals except suckling infants. fifteen types of habitat were recognized and defined in terms of their structural features. in the initial phase of the study ... | 1984 | 32160718 |
| movement patterns of a group of free-ranging mountain gorillas (gorilla gorilla beringei) and their relation to food availability. | relationships between the movement patterns of free-ranging mountain gorillas (gorilla gorilla beringei) and the abundance and distribution of foods in their home range were examined. during an 18-month field study, the ranging of one group of g. gorilla beringei was recorded on a 250 × 250 m grid system, from which measurements of frequency and duration of use, travel rate, and rate of revisitation of each quadrangle by the group were derived. food items were sampled in selected quadrangles thr ... | 1984 | 32131568 |
| composition and variability of mountain gorilla diets in the central virungas. | data are presented here on the feeding ecology of wild mountain gorillas (gorilla gorilla beringei) which were observed for approximately 2,400 hours over a 17-month period in the parc national des volcans, rwanda. aspects of the relationship between the composition, diversity, and temporal consistency of the gorillas' diet and spatial and temporal variability in food distribution patterns are described. mountain gorillas are folivores that show considerable specialization on plant parts, specie ... | 1984 | 32106635 |
| fertility in the male gorilla (gorilla gorilla): relationship to semen parameters and serum hormones. | circulating levels of steroid and protein hormones were measured in 17 adult male lowland gorillas (gorilla gorilla). the population included both fertile and infertile males as identified by previous siring of offspring and presence or absence of spermatozoa in the ejaculate obtained by rectal probe electrostimulation. correlations were sought between levels of testosterone, dihydrotestosterone, androstenedione, estrone, estradiol, progesterone, 170h-progesterone, dihydroepiandrosterone, lutein ... | 1982 | 32192241 |
| urinary immunoreactive estrogen and pregnanediol-3-glucuronide during the normal menstrual cycle of the female lowland gorilla (gorilla gorilla). | urine samples were taken daily during 22 menstrual cycles of six normal adult female gorillas. urine was analyzed for total immunoreactive estrogens (et) and pregnanediol-3-glucuronide (pdg) and indexed by creatinine (cr). an average cycle length of 32 ± 1 days (mean ± se) with a range of 25-42 days is reported. estrogen values range from 4 to 128 ng/mg cr and show a midcycle peak and a midluteal rise. pdg values range from 0.01 to 2.4 μg/mg cr and display a low, flat follicular phase followed b ... | 1982 | 31995900 |
| the development of infant play in a captive group of lowland gorillas (gorilla gorilla gorilla). | three infant gorillas born at the yerkes regional primate research center of emory university were studied during their first year and one-half of life for various aspects of behavior, including solitary and social play, using both focal animal and one-zero sampling. the appearance of play in these infants followed a developmental trend, beginning with mother-infant play, and followed by solitary play, and then social play among peers. mothers were initially very vigilant, repeatedly interruptin ... | 1981 | 31995947 |