Publications

preference transitivity and symbolic representation in capuchin monkeys (cebus apella).	can non-human animals comprehend and employ symbols? the most convincing empirical evidence comes from language-trained apes, but little is known about this ability in monkeys. tokens can be regarded as symbols since they are inherently non-valuable objects that acquire an arbitrarily assigned value upon exchange with an experimenter. recent evidence suggested that capuchin monkeys, which diverged from the human lineage 35 million years ago, can estimate, represent and combine token quantities. ...	2008	18545670
the effects of adenosine a2a receptor antagonists on haloperidol-induced movement disorders in primates.	adenosine and dopamine interact within the striatum to control striatopallidal output and globus pallidus gaba release. manipulating striatal adenosine transmission via blockade of the a2a receptor subtype can compensate for the reduced dopamine activity within the striatum that underlies movement disorders such as antipsychotic-induced extrapyramidal syndrome (eps) and parkinson's disease (pd). preclinical studies in the rat have demonstrated that adenosine a2a receptor antagonists can attenuat ...	2008	18594798
number and topography of cones, rods and optic nerve axons in new and old world primates.	to better understand the evolution of spatial and color vision, the number and spatial distributions of cones, rods, and optic nerve axon numbers were assessed in seven new world primates (cebus apella, saimiri ustius, saguinus midas niger, alouatta caraya, aotus azarae, calllithrix jacchus, and callicebus moloch). the spatial distribution and number of rods and cones was determined from counts of retinal whole mounts. optic axon number was determined from optic nerve sections by electron micros ...	2008	18598400
natural plasmodium infections in brazilian wild monkeys: reservoirs for human infections?	four hundred and forty-eight samples of total blood from wild monkeys living in areas where human autochthonous malaria cases have been reported were screened for the presence of plasmodium using microscopy and pcr analysis. samples came from the following distinct ecological areas of brazil: atlantic forest (n=140), semideciduous atlantic forest (n=257) and cerrado (a savannah-like habitat) (n=51). thick and thin blood smears of each specimen were examined and plasmodium infection was screened ...	2008	18620330
the effects of fur rubbing on the social behavior of tufted capuchin monkeys.	fur rubbing has often been attributed as a social as well as a medicinal function in capuchin monkeys, yet to date there have been no studies investigating the effects of fur rubbing on subsequent group dynamics. here, we report for the first time how social group cohesion is affected by fur rubbing in tufted capuchin monkeys. fifteen captive capuchins were each observed six times for 45 min, three times following the provision of materials typically used for fur rubbing (onion) and three times ...	2008	18626908
sex differences in play behavior in juvenile tufted capuchin monkeys (cebus apella).	according to the motor training hypothesis, play behavior in juvenile primates improves motor skills that are required in later adult life. sex differences in juvenile play behavior can therefore be expected when adult animals assume distinct sexually dimorphic roles. tufted capuchin monkeys show sexually dimorphic levels of physical antagonism in both inter- and intra-group encounters. accordingly, it can be predicted that juvenile capuchins also show sex differences in social play behavior. to ...	2008	18668302
reproductive parameters of a captive colony of capuchin monkeys (cebus apella) from 1984 to 2006.	this paper presents the results of a demographic analysis of 22 years of data recorded on a colony of tufted capuchin monkeys (cebus apella) in captivity at the cnr primate centre (rome, italy). information is provided on reproduction, sex ratio, inter-birth interval (ibi), seasonality, and body weight. from 1984 to 2006, 46 live births were recorded. there were births in almost all months of the year, but a higher frequency was observed during spring and summer (71.1%). the sex ratio was 1:1 m: ...	2008	18696009
giving is self-rewarding for monkeys.	helping and sharing among humans is often motivated by empathy and accompanied by a sense of satisfaction. to determine whether similar self-rewarding mechanisms may underpin assistance among nonhuman primates, eight female brown capuchin monkeys (cebus apella) underwent testing in a simple choice paradigm. paired with a partner, subjects could select either a "selfish" option that rewarded only themselves, or a "prosocial" option that rewarded both of them. subjects systematically favored the p ...	2008	18757730
ontogeny of manipulative behavior and nut-cracking in young tufted capuchin monkeys (cebus apella): a perception-action perspective.	how do capuchin monkeys learn to use stones to crack open nuts? perception-action theory posits that individuals explore producing varying spatial and force relations among objects and surfaces, thereby learning about affordances of such relations and how to produce them. such learning supports the discovery of tool use. we present longitudinal developmental data from semifree-ranging tufted capuchin monkeys (cebus apella) to evaluate predictions arising from perception-action theory linking man ...	2008	19046151
[complex behavior forms in the lower monkeys in the process of identification of quantitative signs of visual stimuli].	complex behavior forms and the ability of monkeys to recognize and to compare by identity the two-dimensional images and three-dimensional objects of various colors in the amount from 5 to 9 were studied. the study was carried out on two species of the lower monkeys of different levels of phylogenetic development: on rhesus monkeys (macaca mulatta) and on brown capuchins (cebus apella). it has been established that the representatives of the studied monkey species are able to differentiate large ...	2008	18767561
cortical development in brown capuchin monkeys: a structural mri study.	relative to other primates, cebus monkeys display unusually fast postnatal brain growth and motor skill development. the neonatal capuchin brain, at approximately 29-34 g, is a smaller proportion of the adult brain weight (c. 50%) than is the brain of other primates except humans and great apes. here we describe, from a cross-sectional sample, brain development in 29 brown capuchin monkeys (cebus apella) using high-resolution structural magnetic resonance images, focusing on growth patterns in t ...	2008	18805494
evolutionary modifications of human milk composition: evidence from long-chain polyunsaturated fatty acid composition of anthropoid milks.	brain growth in mammals is associated with increased accretion of long-chain polyunsaturated fatty acids (lcpufa) in brain phospholipids. the period of maximum accumulation is during the brain growth spurt. humans have a perinatal brain growth spurt, selectively accumulating docosahexaenoic acid (dha) and other lcpufa from the third trimester through the second year of life. the emphasis on rapid postnatal brain growth and lcpufa transfer during lactation has led to the suggestion that human mil ...	2008	18809203
helping behaviour and regard for others in capuchin monkeys (cebus apella).	altruism is an evolutionary puzzle. to date, much debate has focused on whether helping others without regard to oneself is a uniquely human behaviour, with a variety of empirical studies demonstrating a lack of altruistic behaviour in chimpanzees even when the demands of behaving altruistically seem minimal. by contrast, a recent experiment has demonstrated that chimpanzees will help a human experimenter to obtain an out-of-reach object, irrespective of whether or not they are offered a reward ...	2008	18812309
food competition in a semi-free-ranging cebus apella group.	the competitive regime faced by individuals is fundamental to modelling the evolution of social organization. in this paper, we assess the relative importance of contest and scramble food competition on the social dynamics of a provisioned semi-free-ranging cebus apella group (n = 18). individuals competed directly for provisioned and clumped foods. effects of indirect competition were apparent with individuals foraging in different areas and with increased group dispersion during periods of low ...	2008	18824860
endowment effect in capuchin monkeys.	in humans, the capacity for economically rational choice is constrained by a variety of preference biases: humans evaluate gambles relative to arbitrary reference points; weigh losses heavier than equally sized gains; and demand a higher price for owned goods than for equally preferred goods that are not yet owned. to date, however, fewer studies have examined the origins of these biases. here, we review previous work demonstrating that human economic biases such as loss aversion and reference d ...	2008	18840573
quality before quantity: rapid learning of reverse-reward contingency by capuchin monkeys (cebus apella).	capuchin monkeys (cebus apella) were tested on a reverse-reward task involving different quantities of the same food, or an identical quantity of different foods. all monkeys tested first on the qualitative version spontaneously mastered the task, whereas only one of four spontaneously mastered the quantitative version. no monkey reached criterion when the tasks were switched, although almost all did so following remedial procedures after the study. the results suggest that (a) qualitative rever ...	2008	19014269
[occurrence of infection leishmania spp. and toxoplasma gondii in monkeys (cebus apella) from campo grande, ms].	the aim of this study was research antibodies from infection by leishmania spp. and toxoplasma gondii in nonhuman primates (hnp) and compare the techniques of reaction of indirect immunofluorescence (ifat) and modified agglutination test (mat) for the search of t. gondii. fourteen adults monkeys (cebus apella) were examined, from the centre for rehabilitation of wild animals (cras) from campo grande, ms. the research of anti- leishmania spp. was performed by ifat and research of anti-t. gondii w ...	2008	20059866
technical note: dental microwear textures of "phase i" and "phase ii" facets.	the power stroke of mastication has been traditionally divided into two parts, one which precedes centric occlusion, and the other which follows it-"phase i" and "phase ii," respectively. recent studies of primate mastication have called into question the role of phase ii in food processing, as they have found little muscle activity or accompanying bone strain following centric occlusion. that said, many researchers today look to phase ii facets to relate diet to patterns of dental microwear. th ...	2008	18785631
why do captive tufted capuchins (cebus apella) urine wash?	urine washing (uw) has been observed in numerous species of prosimians and new world monkeys. the functional significance of uw in cebidae, specifically, cebus apella, has not been determined. the objective of our study was to test two major hypotheses related to the function of uw: (1) uw functions as a thermoregulatory mechanism, and (2) uw functions as a means of social communication related to (a) territoriality, (b) sexual encounters, or (c) intragroup aggression/agitation. we collected foc ...	2008	17708538
karyological diagnosis of cebus (primates, platyrrhini) in captivity: detection of hybrids and management program applications.	genetic data are very important for conservation programs in wild population as well as in captive conditions. primates in zoos or breeding centers are often maintained in groups without geographic origin or genetic heritage information. these lead to the incorrect assignment of species and introduce an artificial reproductive barrier, which in turn constitutes inadequate management of the colonies. a karyological analysis of specimens from a primate reproduction center, considered as cebus apel ...	2008	17719190
capuchin monkeys (cebus apella) succeed in a test of quantity conservation.	nonhuman animals demonstrate a number of impressive quantitative skills such as counting sets of items, comparing sets on the basis of the number of items or amount of material, and even responding to simple arithmetic manipulations. in this experiment, capuchin monkeys were presented with a computerized task designed to assess conservation of discrete quantity. monkeys first were trained to select from two horizontal arrays of stimuli the one with the larger number of items. on some trials, aft ...	2008	17549530
symmetrical gaits of cebus apella: implications for the functional significance of diagonal sequence gait in primates.	quadrupedal locomotion of primates is distinguished from the quadrupedalism of many other mammals by several features, including a diagonal sequence (ds) footfall used in symmetrical gaits. this presumably unique feature of primate locomotion has been attributed to an ancestral adaptation for cautious arboreal quadrupedalism on thin, flexible branches. however, the functional significance of ds gait remains largely hypothetical. the study presented here tests hypotheses about the functional sign ...	2008	18155128
histological findings following the use of a space-making device for bone reformation and implant integration in the maxillary sinus of primates.	previous studies have shown that membrane elevation results in predictable bone formation in the maxillary sinus provided that implants can be placed as tent poles. in situations with an extremely thin residual crest which impairs implant placement, it is possible that a space-making device can be used under the sinus membrane to promote bone formation prior to placement of implants.	2009	19392856
intimate social behavior in infant interactions in cebus apella.	the development and individual stability of three intimate social behaviors (lipsmacking, carrying attempts, and facial inspection) were examined for 43 group-housed cebus apella infants from birth to 2 years of age. occurrence of these behaviors was scored from 10-min videotape samples recorded three times a week over that time. frequency of lipsmacking and carrying attempts by adult males, adult females, and juveniles were all highest in early months and decreased to low levels by the end of t ...	2009	18925645
fallback foraging as a way of life: using dietary toughness to compare the fallback signal among capuchins and implications for interpreting morphological variation.	the genus cebus is one of the best extant models for examining the role of fallback foods in primate evolution. cebus includes the tufted capuchins, which exhibit skeletal features for the exploitation of hard and tough foods. paradoxically, these seemingly "specialized" taxa belong to the most ubiquitous group of closely related primates in south america, thriving in a range of different habitats. this appears to be a consequence of their ability to exploit obdurate fallback foods. here we comp ...	2009	19890863
jaw-muscle fiber architecture in tufted capuchins favors generating relatively large muscle forces without compromising jaw gape.	tufted capuchins (sensu lato) are renowned for their dietary flexibility and capacity to exploit hard and tough objects. cebus apella differs from other capuchins in displaying a suite of craniodental features that have been functionally and adaptively linked to their feeding behavior, particularly the generation and dissipation of relatively large jaw forces. we compared fiber architecture of the masseter and temporalis muscles between c. apella (n=12) and two "untufted" capuchins (c. capucinus ...	2009	19875148
cranial suture morphology and its relationship to diet in cebus.	cranial sutures are complex morphological structures. four cebus species (c. albifrons, c. apella, c. capucinus, c. olivaceus) are used here to test the hypothesis that sagittal suture complexity is enhanced in animals that eat materially challenging foods. these primates are ideal for such comparative studies because they are closely related and some are known to exhibit differences in the material properties of the foods they ingest and masticate. specifically, cebus apella is notable among me ...	2009	19833377
'unwilling' versus 'unable': capuchin monkeys' (cebus apella) understanding of human intentional action.	a sensitivity to the intentions behind human action is a crucial developmental achievement in infants. is this intention reading ability a unique and relatively recent product of human evolution and culture, or does this capacity instead have roots in our non-human primate ancestors? recent work by call and colleagues (2004) lends credence to the latter hypothesis, providing evidence that chimpanzees are also sensitive to human intentions. specifically, chimpanzees remained in a testing area lon ...	2009	19840049
[diversity of wild and domestic mammal's intestinal helminths from the caatinga of the parque nacional serra da capivara, southeast of piauí, brazil].	biodiversity studies allow ecosystem assessment and monitoring of environmental changes and impacts. parasite diversity could reflect the host/ parasite coevolutionary process and the environment changes that permit the loss, gain or maintenance of species. this survey used species/morphotypes of helminths eggs found in feces from seven wild mammal species (the groups dasypodidae and large cats, and tamandua tetradactyla, cebus apella, alouatta caraya, cerdocyon thous, pecari tajacu) and from tw ...	2009	20040186
effects of platelet-rich plasma on healing of alveolar socket: split-mouth histological and histometric evaluation in cebus apella monkeys.	the prediction of implant treatment is directly influenced by the quality of the remaining bone after tooth extraction.	2009	20139568
synteny of human chromosomes 14 and 15 in the platyrrhines (primates, platyrrhini).	in order to study the intra- and interspecific variability of the 14/15 association in platyrrhini, we analyzed 15 species from 13 genera, including species that had not been described yet. the dna libraries of human chromosomes 14 and 15 were hybridized to metaphases of alouatta guariba clamitans, a. caraya, a. sara, ateles paniscus chamek, lagothrix lagothricha, brachyteles arachnoides, saguinus midas midas, leontopithecus chrysomelas, callimico goeldii, callithrix sp., cebus apella, aotus nig ...	2009	21637455
grooming, rank, and agonistic support in tufted capuchin monkeys.	studies investigating the relation between allogrooming and social rank in capuchin monkeys (genus cebus) have yielded inconsistent results. in this study, we investigated the relation between grooming, agonistic support, aggression and social rank in a captive group of tufted capuchin monkeys (c. apella). differently from most previous studies, we based our analyses on a relatively large database and studied a group with known genealogical relationships. tufted capuchin females did not exchange ...	2009	19025780
the psychological organization of "uncertainty" responses and "middle" responses: a dissociation in capuchin monkeys (cebus apella).	some studies of nonhuman animals' metacognitive capacity encourage competing low-level, behavioral descriptions of trial-decline responses by animals in uncertainty-monitoring tasks. to evaluate the force of these behavioral descriptions, the authors presented 6 capuchin monkeys (cebus apella) with 2 density discrimination tasks between sparse and dense stimuli. in one task, difficult trials with stimuli near the middle of the density continuum could be declined through an "uncertainty" response ...	2009	19594282
behavior patterns of southern bearded sakis (chiropotes satanas) in the fragmented landscape of eastern brazilian amazonia.	the endangered but poorly studied southern bearded saki, chiropotes satanas, faces extremes of habitat fragmentation throughout its geographic range in eastern amazonia. this article focuses on the behavior of the members of two groups--a large one (30-34 members) in continuous forest (home range=69 ha) and a much smaller one (7 members) on a 17-ha man-made island--at the tucuruí reservoir on the tocantins river. quantitative behavioral data were collected through scan and all-events sampling. b ...	2009	18850586
ricinus communis biocompatibility histological study in the nose of cebus apella monkeys.	bone tissue lesions can be caused by congenital and acquired factors, and result in nasal deformities with cosmetic and functional repercussion. surgical treatment in these cases frequently requires complex reconstructions and the use of biomaterials. the polyurethane derived from castor beans (ricinus communis) has a favorable formulation in terms of ease of processing, flexibility, no emission of toxic vapors and low cost. nonetheless, despite favorable results, studies about the use of castor ...	2009	19649483
rod bipolar cells in the retina of the capuchin monkey (cebus apella): characterization and distribution.	rod bipolar cells in cebus apella monkey retina were identified by an antibody against the alpha isoform of protein kinase c (pkcalpha), which has been shown to selectively identify rod bipolars in two other primates and various mammals. vertical sections were used to confirm the identity of these cells by their characteristic morphology of dendrites and axons. their topographic distribution was assessed in horizontal sections; counts taken along the dorsal, ventral, nasal, and temporal quadrant ...	2009	19709465
folivory or fruit/seed predation for mesopithecus, an earliest colobine from the late miocene of eurasia?	here we compare dental microwear textures from specimens of the fossil genus mesopithecus (cercopithecidae, colobinae) from the late miocene of eastern europe with dental microwear textures from four extant primate species with known dietary differences. results indicate that the dental microwear textures of mesopithecus differ from those of extant leaf eaters alouatta palliata and trachypithecus cristatus and instead resemble more closely those of the occasional hard-object feeders cebus apella ...	2009	19733899
postconflict behaviour in brown capuchin monkeys (cebus apella).	postconflict affiliation has been mostly studied in old world primates, and we still lack comparative research to understand completely the functional value of reconciliation. cebus species display great variability in social characteristics, thereby providing a great opportunity for comparative studies. we recorded 190 agonistic interactions and subsequent postconflict behaviour in a captive group of brown capuchin monkeys (cebus apella). only 26.8% of these conflicts were reconciled. reconcili ...	2009	19923844
in-group conformity sustains different foraging traditions in capuchin monkeys (cebus apella).	decades of research have revealed rich cultural repertoires encompassing multiple traditions in wild great apes, a picture crucially complemented by experimental simulations with captive apes. studies with wild capuchin monkeys, the most encephalized simian species, have indicated a new world convergence on these cultural phenomena, involving multiple traditions and tool use. however, experimental studies to date are in conflict with such findings in concluding that capuchins, like other monkeys ...	2009	19924242
spider monkeys (ateles geoffroyi) and capuchin monkeys (cebus apella) follow gaze around barriers: evidence for perspective taking?	gaze following is an adaptive skill that might have been selected in social species, such as many nonhuman primates, to obtain information about food location, predators, and social interactions. the authors investigated the ability of spider monkeys (ateles geoffroyi) and capuchin monkeys (cebus apella) to follow the gaze of a human around barriers and the presence of "looking back" behavior. in the 1st experiment, a human looked to a target location inside the testing room, whereas in the 2nd ...	2009	19929105
monkeys recognize the faces of group mates in photographs.	nonhuman primates possess a highly developed capacity for face recognition, which resembles the human capacity both cognitively and neurologically. face recognition is typically tested by having subjects compare facial images, whereas there has been virtually no attention to how they connect these images to reality. can nonhuman primates recognize familiar individuals in photographs? such facial identification was examined in brown or tufted capuchin monkeys (cebus apella), a new world primate, ...	2009	19966230
primate community of the tropical rain forests of saracá-taqüera national forest, pará, brazil.	brazil is the richest country in the world in terms of primate species and the amazonian rain forest is one of the richest biomes containing 15 (ca. 90%) of the neotropical primate genera. although considered key elements in conservation strategies, there is only anecdotal information on primates for several protected areas within the region. here we present new data on the community composition of the primates in the saracá-taqüera national forest (429,600 ha), an actively mined, bauxite rich a ...	2009	19967179
pharmacokinetics and pharmacodynamics of interferon beta 1a in cebus apella.	recombinant human interferon (hifn beta) is indicated for the treatment of multiple sclerosis. its effect presents species restriction, thus lacking biological activity on most mammals. although there have been previous studies of the pharmacology of inf beta in old world primates, no data exists on new world primates. therefore, we explored its effect on cebus apella, a new world monkey, describing the pharmacology of this molecule when injected by subcutaneous route in this species.	2009	19054274
navigating two-dimensional mazes: chimpanzees (pan troglodytes) and capuchins (cebus apella sp.) profit from experience differently.	we examined whether navigation is impacted by experience in two species of nonhuman primates. five chimpanzees (pan troglodytes) and seven capuchin monkeys (cebus apella) navigated a cursor, using a joystick, through two-dimensional mazes presented on a computer monitor. subjects completed 192 mazes, each one time. each maze contained one to five choices, and in up to three of these choices, the correct path required moving the cursor away from the euclidean direction toward the goal. some subje ...	2009	19148688
does inequity aversion depend on a frustration effect? a test with capuchin monkeys (cebus apella).	brosnan and de waal (nature 425:297-299, 2003) reported that if a witness monkey saw a model monkey receive a high-value food, the witness was more inclined to reject a previously acceptable, but low-value food. later work demonstrated that this alleged inequity aversion might be due to frustration induced by switching subjects from their role as models receiving a high-value food to the role of witnesses receiving a low-value food. in the present study, pairs of female capuchins exchanged a tok ...	2009	19184138
social facilitation of exploratory foraging behavior in capuchin monkeys (cebus apella).	much of the research on animal social learning focuses on complex cognitive functions such as imitation and emulation. when compelling evidence for such processes is not forthcoming, simpler processes are often assumed but rarely directly tested for. in this study we address the phenomenon of social facilitation, whereby the presence of a feeding conspecific is hypothesized to affect the motivation and behavior of the subject, elevating the likelihood of exploration and discovery in relation to ...	2009	19235756
tufted capuchin monkeys (cebus apella) spontaneously use visual but not acoustic information to find hidden food items.	foraging choices in tufted capuchins monkeys are guided by perceptual, cognitive, and motivational factors, but little is known about how these factors might interact. the present study investigates how different types of sensory information affect capuchins' ability to locate hidden food. in two experiments, capuchins were presented with two cups, one baited and one empty. monkeys were given visual, acoustic, or acoustic-visual information related to the baited cup, the empty cup, or both baite ...	2009	19236142
the relative use of proximity, shape similarity, and orientation as visual perceptual grouping cues in tufted capuchin monkeys (cebus apella) and humans (homo sapiens).	recent experimental results suggest that human and nonhuman primates differ in how they process visual information to assemble component parts into global shapes. to assess whether some of the observed differences in perceptual grouping could be accounted for by the prevalence of different grouping factors in different species, we carried out 2 experiments designed to evaluate the relative use of proximity, similarity of shape, and orientation as grouping cues in humans (homo sapiens) and capuch ...	2009	19236145
metamemory in tufted capuchin monkeys (cebus apella).	whereas evidence for metacognition by nonhuman primates has been obtained in great apes and old world monkeys, it is weaker in new world monkeys. for instance, capuchin monkeys may fail to recognize their own knowledge of the location of invisible bait. in the present study, we tested whether tufted capuchin monkeys would flexibly change their behavior in a delayed matching-to-sample (dmts) test depending upon the strength of their memory trace of the sample. in experiment 1, two monkeys were te ...	2009	19242741
interspecific primate associations in amazonian flooded and unflooded forests.	stable associations between two or more primate species are a prominent feature of neotropical forest vertebrate communities and many studies have addressed their prevalence, and their costs and benefits. however, little is known about the influence of different habitat types on the frequency, seasonality, and composition of mixed-species groups in amazonian forest primates. here we examine the features of interspecific primate groups in a large mosaic of flooded (várzea and igapó) and unflooded ...	2009	19242777
is the positive c-kit immunostaining associated with the presence of cells analogous to the intersticial cells of cajal in the ciliary muscle?	interstitial cells of cajal were identified in the gastrointestinal tract of several species, with close relation to the enteric nervous system. since it was recognized that interstitial cells of cajal express the gene product of c-kit, we performed immunohistochemistry for c-kit protein in ciliary muscle specimens of monkeys' eyes.	2009	19347121
a comparative study of corpus callosum size and signal intensity in capuchin monkeys (cebus apella) and chimpanzees (pan troglodytes).	the evolution of corpus callosum (cc) was integral to the development of higher cognitive processes and hemispheric specialization. an examination of cc morphology and organization across different primate species will further our understanding of the evolution of these specified functions. using magnetic resonance imaging (mri) as a non-invasive technique to measure cc size and to approximate the degree of myelination in the corpus callosum, we report differences in cc morphology and organizati ...	2009	19356692
[study of capability for recognition of complex visual stimuli of different quantities in the lower monkeys].	capability of monkeys for identification of quantitative signs has been studied at recognition and comparison of two- and three-dimensional objects in quantities from 1 to 8. the work was carried out on two species of the low monkeys: rhesus macaque (macaca mulatta) and brown capuchins (cebus apella). the studied representatives of the monkeys have been established to be able to differentiate planar images and casts of cherries in various quantity combinations from 1 to 8 and to identify identic ...	2009	19370996
face recognition in capuchin monkeys (cebus apella).	primates live in complex social groups that necessitate recognition of the individuals with whom they interact. in humans, faces provide a visual means by which to gain information such as identity, allowing us to distinguish between both familiar and unfamiliar individuals. the current study used a computerized oddity task to investigate whether a new world primate, cebus apella, can discriminate the faces of in-group and out-group conspecifics based on identity. the current study, improved on ...	2009	19450022
developmental sources of conservation and variation in the evolution of the primate eye.	conserved developmental programs, such as the order of neurogenesis in the mammalian eye, suggest the presence of useful features for evolutionary stability and variability. the owl monkey, aotus azarae, has developed a fully nocturnal retina in recent evolution. description and quantification of cell cycle kinetics show that embryonic cytogenesis is extended in aotus compared with the diurnal new world monkey cebus apella. combined with the conserved mammalian pattern of retinal cell specificat ...	2009	19451636
suppression of ovulation by a synthetic progestin in the capuchin monkey.	from the limited research in new world monkeys it is not clear whether they are as sensitive to the antiovulatory effects of synthetic progestins as noted in human beings. we examined whether levonorgestrel prevented ovulation in the capuchin monkey.	2009	19470082
monkeys crying wolf? tufted capuchin monkeys use anti-predator calls to usurp resources from conspecifics.	the use of 'tactical deception' is argued to have been important in the cognitive evolution of the order primates, but systematic studies of active deception in wild non-human primates are scant. this study tests whether wild tufted capuchin monkeys (cebus apella nigritus) use alarm calls in a functionally deceptive manner to usurp food resources. if capuchins use alarm calls 'deceptively', it was predicted that false alarms should be: (i) given by subordinates more than by dominants, (ii) more ...	2009	19493903
picture processing in tufted capuchin monkeys (cebus apella).	although pictures are frequently used in place of real objects to investigate various aspects of cognition in different non-human species, there is little evidence that animals treat pictorial stimuli as representations of the real objects. in the present study, we carried out four experiments designed to assess picture processing in tufted capuchin monkeys (cebus apella), using a simultaneous matching-to-sample (mts) task. the results of the first three experiments indicate that capuchins are a ...	2009	19501136
sylvian fissure asymmetry in capuchin monkeys (cebus apella).	asymmetries of the sylvian fissure (sf) are believed to reflect an enlargement of the posterior temporal lobe, particularly a region that corresponds to part of wernicke's area in humans. in nonhuman primates the homologue to the region may be involved in the discrimination and processing of species-specific vocalisations. as capuchin monkeys are large-brained, socially complex primates with a rich vocal repertoire, it was hypothesised that they would display asymmetry of the sf. we used high-re ...	2009	18759195
an assessment of memory awareness in tufted capuchin monkeys (cebus apella).	humans, apes, and rhesus monkeys demonstrate memory awareness by collecting information when ignorant and acting immediately when informed. in this study, five capuchin monkeys searched for food after either watching the experimenter bait one of four opaque tubes (seen trials), or not watching (unseen trials). monkeys with memory awareness should look into the tubes before making a selection only on unseen trials because on seen trials they already know the location of the food. in experiment 1, ...	2009	18712532
quantity judgments of sequentially presented food items by capuchin monkeys (cebus apella).	recent assessments have shown that capuchin monkeys, like chimpanzees and other old world primate species, are sensitive to quantitative differences between sets of visible stimuli. in the present study, we examined capuchins' performance in a more sophisticated quantity judgment task that required the ability to form representations of food quantities while viewing the quantities only one piece at a time. in three experiments, we presented monkeys with the choice between two sets of discrete ho ...	2009	18670794
capuchin monkeys (cebus apella) respond to video images of themselves.	many studies have used mirror-image stimulation in attempts to find self-recognition in monkeys. however, very few studies have presented monkeys with video images of themselves; the present study is the first to do so with capuchin monkeys. six tufted capuchin monkeys were individually exposed to live face-on and side-on video images of themselves (experimental phase 1). both video screens initially elicited considerable interest. two adult males looked preferentially at their face-on image, wh ...	2009	18574604
tufted capuchin monkeys (cebus apella) show understanding of human attentional states when requesting food held by a human.	researchers have investigated to what extent non-human primates understand others' attentional states, as this ability is considered an important prerequisite for theory of mind. however, previous studies using food requesting tasks have failed to show that non-human primates attribute perception to others as a function of their attentional states. one possible reason is that food requesting tasks may require subjects not only to take into account an experimenter's attentional state but also to ...	2010	19517147
effects of follicular phase and oocyte-cumulus complexes quality on the protein profile and in vitro oocyte meiosis competence in cebus apella.	to study the protein profile of oocytes and cumulus cells from different sized follicles throughout the follicular phase and to asses the ability of oocytes to progress from the dictyate to metaphase ii (mii) stage.	2010	19560758
how to spend a token? trade-offs between food variety and food preference in tufted capuchin monkeys (cebus apella).	humans and non-human animals often choose among different alternatives by seeking variety. here we assessed whether variety-seeking, i.e. the tendency to look for diversity in services and goods, occurs in capuchin monkeys--south-american primates which--as humans--are omnivorous and susceptible to food monotony. capuchins chose between a variety-token, that allowed to select one among 10 different foods (one more-preferred and nine less-preferred) and a monotony-token, that--upon exchange with ...	2010	20026196
living together: behavior and welfare in single and mixed species groups of capuchin (cebus apella) and squirrel monkeys (saimiri sciureus).	there are potential advantages of housing primates in mixed species exhibits for both the visiting public and the primates themselves. if the primates naturally associate in the wild, it may be more educational and enjoyable for the public to view. increases in social complexity and stimulation may be enriching for the primates. however, mixed species exhibits might also create welfare problems such as stress from interspecific aggression. we present data on the behavior of single and mixed spec ...	2010	19790191
milk composition of captive tufted capuchins (cebus apella).	little is known about the milk composition of nonhuman primates, and it has never been examined in capuchin monkeys (genus cebus). this article reports on the macronutrient milk composition (fat, crude protein (cp), lactose, dry matter (dm), and total gross energy (ge)) of captive housed tufted capuchins (cebus apella) (n=8). c. apella milk averaged 5.22% fat, 2.40% cp, 6.94% lactose, 16.48% dm, and 0.89 kcal/g. fat was the most variable macronutrient and was significantly higher in samples coll ...	2010	19827136
capuchin monkeys (cebus apella) are sensitive to others' reward: an experimental analysis of food-choice for conspecifics.	the issue whether non-human primates have other-regarding preference and/or inequity aversion has been under debate. we investigated whether tufted capuchin monkeys are sensitive to others' reward in various experimental food sharing settings. two monkeys faced each other. the operator monkey chose one of two food containers placed between the participants, each containing a food item for him/herself and another for the recipient. the recipient passively received either high- or low-value food d ...	2010	19609580
searching in the middle-capuchins' (cebus apella) and bonobos' (pan paniscus) behavior during a spatial search task.	in this study we show that bonobos and capuchin monkeys can learn to search in the middle of a landmark configuration in a small-scale space. five bonobos (pan paniscus) and 2 capuchin monkeys (cebus apella) were tested in a series of experiments with the expansion test paradigm. the primates were trained to search in the middle of a 4- or 2-landmark configuration, and were then tested with the same configuration expanded. neither species searched in the middle of the expanded 4-landmark configu ...	2010	20141320
conditional copying fidelity in capuchin monkeys (cebus apella).	in the last two decades, it became largely accepted that monkeys show little, if any, copying fidelity. however, some recent studies have begun to challenge this notion. to explore reasons for such contrary findings, we designed a foraging apparatus so that in each of two experiments with capuchin monkeys (cebus apella), a model would demonstrate one of two alternative methods to obtain food. the apparatus had a v-shaped track on which a panel could be slid up left or right from the center to re ...	2010	20175594
the development of the basal ganglia in capuchin monkeys (cebus apella).	the basal ganglia are subcortical structures involved in the planning, initiation and regulation of movement as well as a variety of non-motor, cognitive and affective functions. capuchin monkeys share several important characteristics of development with humans, including a prolonged infancy and juvenile period, a long lifespan, and complex manipulative abilities. this makes capuchins important comparative models for understanding age-related neuroanatomical changes in these structures. here we ...	2010	20227397
a capuchin monkey (cebus apella) uses video to find food.	we examined the ability of capuchin monkeys to use video without immediate visual-kinaesthetic feedback as a source of information to guide their action in the 3-dimensional world. in experiment 1, 2 capuchins learned to retrieve food under 1 of 2 different objects in 1 cage after watching the experimenter hiding food under 1 of 2 replica objects while in another cage. information space and retrieval space were thus separate. the performance criterion was 71% first correct choices in blocks of 2 ...	2010	20357474
monkeys fail to reciprocate in an exchange task.	exchanges form the basis of human economies. animals too can engage in reciprocal interactions but they do not barter goods like humans, which raises the question of the abilities necessary for trading to occur. previous studies have shown that non-human primates can exchange food with human partners. here, we tested the ability of brown capuchin monkeys and tonkean macaques to reciprocate in a task requiring two conspecifics to exchange tokens in order to obtain rewards from an experimenter. we ...	2010	20473699
development of skilled detection and extraction of embedded prey by wild brown capuchin monkeys (cebus apella apella).	brown capuchin monkeys (cebus apella apella) in suriname forage on larvae enclosed within healthy bamboo stalks. we applied the searching versus handling dichotomy of optimal foraging models to highlight developmental processes contributing to foraging on embedded prey. larvae acquisition begins with search; selecting an appropriate stalk and locating the embedded larvae; followed by handling, ripping the stalk open, and extracting the larvae. although extraction behaviors were present at low ra ...	2010	20476819
delay of gratification in capuchin monkeys (cebus apella) and squirrel monkeys (saimiri sciureus).	in two separate series of experiments four capuchin monkeys (cebus apella) and four squirrel monkeys (saimiri sciureus) were given demonstration trials in which a human transferred six pieces of food, one by one, from out of each monkey's reach to within reach. on test trials the monkey could reach for the transferred food at any time, an action that ended the trial. therefore, it was in the monkey's interest to allow food items to accumulate before reaching for food. no capuchin monkey showed d ...	2010	20476820
hippocampus and dentate gyrus of the cebus monkey: architectonic and stereological study.	behavioral, electrophysiological, and anatomical assays of non-human primates have provided substantial evidence that the hippocampus and dentate gyrus are essential for memory consolidation. however, a single anatomical and stereological investigation of these regions has been done in new world primates to complement those assays. the aim of the present study was to describe the cyto-, myelo-, and histochemical architecture of the hippocampus and dentate gyrus, and to use the optical fractionat ...	2010	20558278
identity concept learning in matching-to-sample tasks by tufted capuchin monkeys (cebus apella).	the abstract concept of equivalence is considered one of the bases of higher-order cognition, and it has been the subject of considerable research in comparative cognition. this study examined the conditions under which tufted capuchin monkeys (cebus apella) are able to acquire an identity concept. six capuchin monkeys were trained to solve a visual matching-to-sample (mts) task on the basis of perceptual identity. the acquisition of the identity rule was inferred from the subject's ability to s ...	2010	20574839
the ontogeny of handling hard-to-process food in wild brown capuchins (cebus apella apella): evidence from foraging on the fruit of maximiliana maripa.	we examined age-related differences in wild brown capuchins' foraging efficiency and the food-processing behaviors directed toward maripa palm fruit (maximiliana maripa). a detailed comparison of the different foraging techniques showed that plucking the fruit from the infructescence constituted the main difficulty of this task. foraging efficiency tended to increase with age, with a threshold at which sufficient strength allowed immatures by the age of three to reach adult-level efficiency. you ...	2010	20575045
preladenant, a selective a(2a) receptor antagonist, is active in primate models of movement disorders.	parkinson's disease (pd) and extrapyramidal syndrome (eps) are movement disorders that result from degeneration of the dopaminergic input to the striatum and chronic inhibition of striatal dopamine d(2) receptors by antipsychotics, respectively. adenosine a(2a) receptors are selectively localized in the basal ganglia, primarily in the striatopallidal ("indirect") pathway, where they appear to operate in concert with d(2) receptors and have been suggested to drive striatopallidal output balance. ...	2010	20655910
dioctophyma renale (goeze, 1782) in the abdominal cavity of a capuchin monkey (cebus apella), brazil.	this study reports a case of parasitism by dioctophyma renale (goeze, 1762) encysted in the abdominal cavity of a capuchin monkey (cebus apella) coming from the centro nacional de primatas, brazil. the animal was sent to the veterinary clinic sector with an increase in abdominal volume and no occurrence of any other clinical signs. upon palpation, a movable circular mass with a diameter of approximately 10 cm was found. urinalysis, complete blood count and serum biochemistry were performed witho ...	2010	20691541
capuchins (cebus apella) can solve a means-end problem.	three capuchin monkeys (cebus apella) were tested on a 2-choice discrimination task designed to examine their knowledge of support, modeled after hauser, kralik, and botto-mahan's (1999) experiments with tamarins. this task involved a choice between 2 pieces of cloth, including 1 with a food reward placed on its surface, and a second cloth with the food reward next to its surface. after reliably solving the basic problem, the capuchins were tested with various alternations of the original food r ...	2010	20695658
the effect of environmental enrichment on the behavior of captive tufted capuchin monkeys (cebus apella).	the authors provided different forms of environmental enrichment to six old laboratory male tufted capuchin monkeys (cebus apella) and studied the behavior of the monkeys during a baseline period and during three enrichment periods. each observation period lasted 5 d, with an interval of 6 d between periods. during the first enrichment period, the authors provided buster cubes and wood cylinders with drilled holes filled with gum arabic. during the second enrichment period, monkeys were provided ...	2010	20729828
[genetic methods for the reintroduction of primates saguinus, aotus and cebus (primates: cebidae) seized in bogota, colombia].	primates are one of more confiscated taxa by the environmental authorities in bogota, colombia. during 2008, 133 monkeys were confiscated; samples from 115 of them were sequenced by the mitochondrial cythocrome oxidase ii gene (mtcoii) and 112 sequences obtained were of high quality. these sequences were compared with those obtained by our research group from individuals directly sampled in the field, with precise geographic origin. so, a more specific geographic area of the colombian territory ...	2010	20737854
can nonhuman primates use tokens to represent and sum quantities?	it is unclear whether nonhuman animals can use physical tokens to flexibly represent various quantities by combining token values. previous studies showed that chimpanzees (pan troglodytes) and a macaque (macaca mulatta) were only partly successful in tests involving sets of different-looking food containers representing different food quantities, while some capuchin monkeys (cebus apella) have shown greater success in tests involving sets of various concrete objects representing different food ...	2010	20836596
effects of cannabinoid cb(1) receptor agonism and antagonism on skf81297-induced dyskinesia and haloperidol-induced dystonia in cebus apella monkeys.	antipsychotic drugs may cause extrapyramidal symptoms (eps), such as dyskinesia and dystonia. these effects are believed to involve dysfunctional striatal dopamine transmission. patients with schizophrenia show increased prevalence of cannabis abuse and this has been linked to severity of eps. endocannabinoids modulate striatal dopamine activity via type 1 cannabinoid (cb(1)) receptors, and studies in rats and humans suggest beneficial effects of cb(1) ligands on eps. the present study explored ...	2010	21029743
chemical characterization of oligosaccharides in the milk of six species of new and old world monkeys.	human and great ape milks contain a diverse array of milk oligosaccharides, but little is known about the milk oligosaccharides of other primates, and how they differ among taxa. neutral and acidic oligosaccharides were isolated from the milk of three species of old world or catarrhine monkeys (cercopithecidae: rhesus macaque (macaca mulatta), toque macaque (macaca sinica) and hamadryas baboon (papio hamadryas)) and three of new world or platyrrhine monkeys (cebidae: tufted capuchin (cebus apell ...	2010	21127965
semen coagulum liquefaction, sperm activation and cryopreservation of capuchin monkey (cebus apella) semen in coconut water solution (cws) and tes-tris.	the objectives of the present study were to test the effect of coconut water solution and tes-tris on the seminal coagulum liquefaction, sperm activation in fresh diluted semen, and on the cryopreservation of semen from capuchin monkeys (cebus apella). semen was collected from six males by electro-ejaculation, diluted in tes-tris or coconut water solution (cws), and incubated at 35°c until the coagulated fraction of the semen was completely liquefied. in the experiment i, after liquefaction, sam ...	2010	21129865
can traditions emerge from the interaction of stimulus enhancement and reinforcement learning? an experimental model.	the study of social learning in captivity and behavioral traditions in the wild are two burgeoning areas of research, but few empirical studies have tested how learning mechanisms produce emergent patterns of tradition. studies have examined how social learning mechanisms that are cognitively complex and possessed by few species, such as imitation, result in traditional patterns, yet traditional patterns are also exhibited by species that may not possess such mechanisms. we propose an explicit m ...	2010	21135912
development of maze navigation by tufted capuchins (cebus apella).	theories of spatial navigation hypothesize that animals use vector or topological information to choose routes, often including detours, to move objects or themselves to goals. we assessed adult capuchin monkeys' (cebus apella) navigation through 192 virtual two-dimensional mazes that incorporated detour problems. six monkeys initially were significantly less likely to choose the correct paths when detours were required than when not. three of the six monkeys repeatedly practiced the 192 mazes t ...	2010	21138761
mitochondrial divergence between 2 populations of the hooded capuchin, cebus (sapajus) cay (platyrrhini, primates).	we analyzed the molecular divergence of 2 separate populations of cebus apella paraguayanus, recently considered a junior synonym of cebus cay, and estimated its time of separation from c. apella. cytochrome b dna from 23 c. cay from brazil and 9 from paraguay showed 24 haplotypes (20 and 4, respectively), accounting for 29 variable sites (19 transitions and 10 transversions), with 40.0%, 26.7%, and 33.0% replacements at first, second, and third codon positions, respectively. genetic distance be ...	2010	20056682
ontogeny of long bone geometry in capuchin monkeys (cebus albifrons and cebus apella): implications for locomotor development and life history.	studies of a diverse array of animals have found that young individuals often have robust bones for their body size (i.e. augmented cross-sectional dimensions), limiting fracture risk despite general musculoskeletal immaturity. however, previous research has focused primarily on precocial taxa (e.g. rodents, lagomorphs, bovids, goats and emu). in this study, we examined the ontogenetic scaling of humeral and femoral cross-sectional robusticity in a mixed-longitudinal sample of two slow-growing, ...	2010	19864273
cone photopigment variations in cebus apella monkeys evidenced by electroretinogram measurements and genetic analysis.	we investigated the color vision pattern in cebus apella monkeys by means of electroretinogram measurements (erg) and genetic analysis. based on erg we could discriminate among three types of dichromatic males. among females, this classification is more complex and requires additional genetic analysis. we found five among 10 possible different phenotypes, two trichromats and three dichromats. we also found that cebus present a new allele with spectral peak near 552nm, with the amino acid combina ...	2010	19883678
prey capture efficiency in brown capuchin monkeys (cebus apella) is influenced by sex and corpus callosum morphology.	the diet of capuchin monkeys consists largely of fruits, but these monkeys commonly prey upon insects and other invertebrates as well as vertebrates such as lizards, birds, and fish. capturing small fast-moving prey requires the ability to process complex visuospatial information such as motion detection, shape, and pursuit. here we report the results of an experimental investigation into whether capuchins display sex differences in prey capture efficiency, and whether these differences are asso ...	2010	20077465
gait dynamics of cebus apella during quadrupedalism on different substrates.	primates are distinguished from many mammals by emphasizing arboreal lifestyles. primate arboreal adaptations include specializations for enhancing balance and manipulative skills. compliant gait and diagonal sequence (ds) footfalls are hypothesized mechanisms for improving balance during arboreal quadrupedalism (aq), while simultaneously permitting vertical peak force reductions sustained by limbs, particularly forelimbs (fls). capuchin monkeys (cebus apella) are arboreally-adapted quadrupeds t ...	2010	20091854
image-based red cell counting for wild animals blood.	an image-based red blood cell (rbc) automatic counting system is presented for wild animals blood analysis. images with 2048×1536-pixel resolution acquired on an optical microscope using neubauer chambers are used to evaluate rbc counting for three animal species (leopardus pardalis, cebus apella and nasua nasua) and the error found using the proposed method is similar to that obtained for inter observer visual counting method, i.e., around 10%. smaller errors (e.g., 3%) can be obtained in regio ...	2010	21096766
behavioral and ecological consequences of sex-based differences in gustatory anatomy in cebus apella.	fungiform papillae (fps) are the only gustatory structures on the anterior tongue. taste buds (tbs), which are located in fps, house taste receptors. each tb has a taste pore (tp) by which tastants are transmitted. in humans, fp and tb densities correlate with taste sensitivity and food preferences. females have higher fp densities than males in homo, pan, and cebus. homo, pan, and cebus also have larger brains, slower ontogenetic development, and higher maternal investment in offspring compared ...	2011	22042744
experimental gastric carcinogenesis in cebus apella nonhuman primates.	the evolution of gastric carcinogenesis remains largely unknown. we established two gastric carcinogenesis models in new-world nonhuman primates. in the first model, acp03 gastric cancer cell line was inoculated in 18 animals. in the second model, we treated 6 animals with n-methyl-nitrosourea (mnu). animals with gastric cancer were also treated with canova immunomodulator. clinical, hematologic, and biochemical, including c-reactive protein, folic acid, and homocysteine, analyses were performed ...	2011	21811552
the influence of experimental manipulations on chewing speed during in vivo laboratory research in tufted capuchins (cebus apella).	even though in vivo studies of mastication in living primates are often used to test functional and adaptive hypotheses explaining primate masticatory behavior, we currently have little data addressing how experimental procedures performed in the laboratory influence mastication. the obvious logistical issue in assessing how animal manipulation impacts feeding physiology reflects the difficulty in quantifying mechanical parameters without handling the animal. in this study, we measured chewing c ...	2011	21469081
histological outcomes on the development of new space-making devices for maxillary sinus floor augmentation.	previous studies have pointed out that the mere elevation of the maxillary sinus membrane promotes bone formation without the use of augmentation materials.	2011	19681942
the instantaneous center of rotation of the mandible in nonhuman primates.	kinematic analyses of mandibular movement in humans demonstrate that the mandibular instantaneous center of rotation (icor) is commonly located near the level of the occlusal plane and varies in its position during a chewing sequence. few data are available regarding the location of the icor in nonhuman primates and it remains unclear how the position of the icor varies in association with mastication and/or gape behaviors. icor was quantified throughout the gape cycle in five species of nonhuma ...	2011	21622946