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accepting loss: the temporal limits of reciprocity in brown capuchin monkeys.delayed reciprocity is a potentially important mechanism for cooperation to occur. it is however rarely reported among animals, possibly because it requires special skills like the ability to plan a loss. we tested six brown capuchin monkeys (cebus apella) in such skills. subjects were studied in exchange tasks in which they had to retain a food item for a given time lag before returning it to an experimenter and obtaining a more desirable reward. experiments showed that the subjects could wait ...200616555785
bone reformation and implant integration following maxillary sinus membrane elevation: an experimental study in primates.recent clinical studies have described maxillary sinus floor augmentation by simply elevating the maxillary sinus membrane without the use of adjunctive grafting materials.200616681489
face processing limitation to own species in primates: a comparative study in brown capuchins, tonkean macaques and humans.most primates live in social groups which survival and stability depend on individuals' abilities to create strong social relationships with other group members. the existence of those groups requires to identify individuals and to assign to each of them a social status. individual recognition can be achieved through vocalizations but also through faces. in humans, an efficient system for the processing of own species faces exists. this specialization is achieved through experience with faces of ...200616690230
genetic diversity of oral fusobacterium nucleatum isolated from patients with different clinical conditions.the genetic diversity of 23 oral fusobacterium nucleatum isolated from 15 periodontal patients, eight from seven healthy subjects, nine from nine aids patients and two from two cebus apella monkeys were analyzed. ecori restricted the bacterial dna and 28 ribotypes grouped from a to j groups were obtained. isolates formed 24 ribotypes which were contained into a, b, c, d, e and f groups, and three reference strains and two clinical isolates of a. actinomycetemcomitans, and e. coli cdc formed four ...200616699623
self-control and tool use in tufted capuchin monkeys (cebus apella).self-control is defined as forgoing immediate gratification to obtain a greater reward. tool use may relate to self-control because both behaviors may require foresight and deliberate control over one's actions. the authors assessed 20 capuchin monkeys (cebus apella) for the ability to delay gratification in a tool task. subjects were given rod-shaped food items that could either be consumed immediately or be carried to an apparatus and used to extract a more preferred food. the authors found th ...200616719595
are capuchin monkeys (cebus apella) inequity averse?it has been reported that capuchin monkeys reject a less preferred food (lpf) when they see a partner capuchin receive a more preferred food (pf) for performing the same task. this behaviour was taken as evidence of 'inequity aversion', but an alternative hypothesis is that capuchins reject the lpf because of the mere presence of the pf. we tested this hypothesis in a paradigm, which consisted of presenting two different foods (one pf and one lpf) on a tray and allowing the capuchin to take only ...200616720395
molar microwear in praeanthropus afarensis: evidence for dietary stasis through time and under diverse paleoecological conditions.molar microwear fabrics in extant mammals vary with diet and, more particularly, the physical properties of the items that are consumed. praeanthropus afarensis is well represented in the fossil record over a prolonged and radiometrically controlled temporal span, and reasonably robust paleoecological reconstructions are available for the various localities from which it is known. we therefore examined molar microwear in this species to determine whether diet varied in relation to time or in res ...200616750841
immunohistochemical analysis of subcortical white matter astroglia of infant and adult primate brains, with a note on resident neurons.an immunohistochemical analysis of brain subcortical white matter astroglia from human (infant, adult) and adult monkey (cebus apella, macaca nemestrina) cases without any known neurological disease, is described. expression of synaptic vesicle-associated proteins, excitatory amino acid transporters (eaat1 and eaat2) and gabaa ralpha2 receptor produced coarse punctate labeling in human adult white matter astrocytes. a finer, generalized, punctate labeling was observed in human infants and adult ...200616765327
symmetry and transitivity of conditional relations in monkeys (cebus apella) and pigeons (columba livia).in experiment 1 six monkeys were tested with discriminative relations that were backward relative to their training in a 0-second conditional ("symbolic") matching procedure. although there was some indication of backward associations, the evidence was generally weak, and statistical evaluations did not reach conventional significance levels. unlike children, who show backward associations to the point of symmetry, monkeys and pigeons display at best only weak and transient backward associations ...198516812425
exchange, affiliation, and protective interventions in semifree-ranging brown capuchin monkeys (cebus apella).the "social intelligence" hypothesis proposes that intelligence evolved as a consequence of the need for behavioral maneuvering to deal with the complexities of social life. as a result, coalitions have received considerable attention. here we present the patterns of coalitionary behavior observed in a semifree-ranging group of cebus apella and explore the effects of kinship, spatial proximity, and rank. in contrast to descriptions of old world monkeys and to some descriptions of capuchins, kins ...200616847972
substrate optimization in nut cracking by capuchin monkeys (cebus apella).we conducted an experiment to examine the effect of substrate on the nut-cracking behavior of a group of semicaptive capuchin monkeys. we wanted to determine whether tufted capuchin monkeys were selective in choosing the substrate on which they pound nuts, and whether the choice of substrate affected the outcome. eight adult females and eight juveniles were provided with nuts in the outdoor facility. we found that 1) all adult females and three young capuchins succeeded in cracking nuts; 2) they ...200616892415
[presence of igm antibodies for leptospira interrogans in wild animals from tocantins state, 2002].four hundred and twenty-seven serum samples of wild animals were tested against 18 serovars of leptospira interrogans. of 286 samples of cebus apella, 46 (16.1%) were positive for the serovars pomona, brasiliensis, mini, swajizak, grippotyphosa, sarmin, fluminense, autumnalis, hebdomadis, guaratuba, javanica and icterohaemorrhagiae. of 82 samples of alouatta caraya, 2 (2.4%) were positive for the serovars mangus and fluminense. of 31 samples of nasua nasua, 4 (12.9%) were positive for the serova ...200616906258
dental microwear texture analysis: technical considerations.dental microwear analysis is commonly used to infer aspects of diet in extinct primates. conventional methods of microwear analysis have usually been limited to two-dimensional imaging studies using a scanning electron microscope and the identification of apparent individual features. these methods have proved time-consuming and prone to subjectivity and observer error. here we describe a new methodological approach to microwear: dental microwear texture analysis, based on three-dimensional surf ...200616908052
i know you are not looking at me: capuchin monkeys' (cebus apella) sensitivity to human attentional states.the present study asked whether capuchin monkeys recognize human attentional states. the monkeys requested food from the experimenter by extending an arm (pointing) toward the baited one of two transparent cups. on regular trials the experimenter gave the food immediately to the monkeys upon pointing but on randomly inserted test trials she ignored the pointing for 5 s during which she displayed different attentional states. the monkeys looked at the experimenter's face longer when she looked at ...200716944232
distribution of calbindin-28kd and parvalbumin in v1 in normal adult cebus apella monkeys and in monkeys with retinal lesions.several proteins have their normal patterns of distributions altered by monocular visual deprivation. we studied the distribution of the calcium-binding proteins calbindin-28kd (cb) and parvalbumin (pv) in v1 in normal adult cebus apella monkeys and in monkeys with monocular retinal lesions. in normal monkeys, the interblobs regions in layers 2/3 and the layer 4b are intensely labeled for cb, while pv reaction showed a complementary labeling pattern with a stronger staining in layers 4a, 4c and ...200616952336
hemorrhoids: an experimental model in monkeys.hemorrhoids are a matter of concern due to a painful outcome. we describe a simple, easy and reliable experimental model to produce hemorrhoids in monkeys.200616981041
how capuchin monkeys (cebus apella) quantify objects and substances.humans and nonhuman animals appear to share a capacity for nonverbal quantity representations. but what are the limits of these abilities? results of previous research with human infants suggest that the ontological status of an entity as an object or a substance affects infants' ability to quantify it. we ask whether the same is true for another primate species-the new world monkey cebus apella. we tested capuchin monkeys' ability to select the greater of two quantities of either discrete objec ...200617115863
the design, synthesis, and evaluation of organ-specific iron chelators.a series of iron chelators, three (s)-4,5-dihydro-2-(2-hydroxyphenyl)-4-methyl-4-thiazolecarboxylic acid (dadft) and three (s)-4,5-dihydro-2-(2-hydroxyphenyl)-4-thiazolecarboxylic acid (dadmdft) analogues are synthesized and assessed for their lipophilicity (log papp), iron-clearing efficiency (ice) in rodents and iron-loaded primates (cebus apella), toxicity in rodents, and organ distribution in rodents. the results lead to a number of generalizations useful in chelator design strategies. in ro ...200617125256
hand use by tufted capuchins (cebus apella) to extract a small food item from a tube: digit movements, hand preference, and performance.the aim of this study was to analyze the manual patterns used by tufted capuchin monkeys (cebus apella) to retrieve a small food item from a narrow tube, with special attention focused on the independent use of single fingers, fine digit movements, hand preference, and intermanual differences in the time it took the monkeys to obtain the food. the capuchins (n = 20) mainly used their forefinger to extract the food from the tube. the simultaneous use of the index and middle fingers occurred less ...200717146792
partner effects on food consumption in brown capuchin monkeys.it has been claimed that capuchin monkeys (cebus apella) show inequity aversion in relation to food rewards for a simple exchange task. however, other factors may affect the willingness of a monkey to consume foods of high or low value in the presence of a conspecific. in this study, pairs of monkeys were presented with unequally valued foods, but without any task-performance: they simply received the food under four experimental conditions. by looking at the rate of collection and consumption o ...200717146793
the capuchin, the howler, and the caatinga: seed dispersal by monkeys in a threatened brazilian forest.regeneration of the brazilian caatinga forest may be restricted by the naturally low diversity and density of fruit-eating animals, which has been aggravated by local faunal extinction induced by human activities. we made a preliminary evaluation of the potential seed-dispersal role of capuchin (cebus apella libidinosus) and howler monkeys (alouatta caraya) in serra da capivara national park. the monkeys dispersed at least 26 species. alouatta dispersed larger seeds than cebus, and the two speci ...200717146800
stone banging by wild capuchin monkeys: an unusual auditory display.primates often react to possible predators by using intimidation displays, although the occurrence of these displays is dependent on the risk of predation. functional explanations for these kinds of displays range from sexual selection to predator deterrence. the ability to respond to different predators can be socially acquired, and social traditions could explain population differences in response to the same potential predator. here i report wild groups of cebus apella libidinosus banging sto ...200717170555
cortisol response and ovarian hormones in juvenile and cycling female cebus monkeys: effect of stress and dexamethasone.we examined cortisol profiles in relation to ovarian hormones and their response to a repeated composite stressor with and without dexamethasone suppression. to evaluate the day-to-day changes in circulating cortisol relative to ovarian hormones, we subjected five adult female cebus apella monkeys daily to restraint, sedation, transport to a neighboring room for femoral venipuncture, and return to the cage throughout the menstrual cycle. the cortisol response to the repeated stressor for blood c ...200717177312
premorbid exercising in specific cognitive tasks prevents impairment of performance in parkinsonian monkeys.adult cebus apella monkeys were exposed to either one, two or four series of cognitive tasks that place a demand on working memory and inhibitory control (spatial delayed response and object retrieval detour), before administration of the neurotoxin 1-methyl-1-4-phenyl-1,2,3,6-tetrahydropyridine (mptp). following mptp treatment, monkeys receiving more than one series successfully reached criteria at delays similar to those attained during the pre-mptp stage for the spatial delayed response task ...200717196188
response toward novel stimuli in a group of tufted capuchins (cebus libidinosus) in brasília national park, brazil.we investigated responses toward novel foods and novel objects by wild capuchins that routinely exploit visitors' foods in brasília national park. given the capuchins' daily exposure to human foods and objects, we expected them to be more explorative toward novel foods and objects compared to capuchins that are not habituated to visitors. however, since the safety and palatability of potential foods have to be learned, we also expected the capuchins to be cautious about eating novel foods, as ha ...200717216622
the relationship between locomotor behavior and limb morphology in brown (cebus apella) and weeper (cebus olivaceus) capuchins.this study is a comparison of locomotor behavior and postcranial form in two species of capuchin monkey, the brown capuchin (cebus apella), and the weeper capuchin (cebus olivaceus). behavioral data from groups of wild c. apella and c. olivaceus in guyana were collected during the period of december 1999 through november 2000. postcranial variables including 40 measurements and three indices were taken from 43 adult and subadult specimens of c. apella and 14 adult and subadult specimens of c. ol ...200717253617
mark tests for mirror self-recognition in capuchin monkeys (cebus apella) trained to touch marks.in experiment 1, three capuchin monkeys (cebus apella) were exposed to a mirror in their home cage for 3 days and then given food treats for touching orange marks located on the surface of an experimental chamber. following training, a mirror was added to the chamber to see if the monkeys would use it to guide non-reinforced contacts with an orange mark on their foreheads that was only visible as a mirror reflection (mark test). two monkeys touched the head-mark more often with the mirror presen ...200717253635
effects of intra-nasally administered testosterone on sexual proceptive behavior in female capuchin monkeys (cebus apella).sexual dysfunction in the female has been associated with a decrease in androgen levels, which can be reversed by testosterone treatment, however, bearing the risk of adverse side effects. nasally administered testosterone could be an effective method for androgenic treatment avoiding the first-pass intestinal and hepatic metabolism and side effects. here we examined the effects of chronic intranasal administration of testosterone on sexual behavior in female capuchin monkeys (cebus apella) that ...200717280726
facial displays in young tufted capuchin monkeys (cebus apella): appearance, meaning, context and target.facial displays are important for communication, and their ontogeny has been studied primarily in chimpanzees and macaques. we investigated the ontogeny, communicative function and target of facial displays in cebus apella. our results show that facial displays are absent at birth and develop as infants grow older. lip-smacking appears first (at about 1 month of age), followed by scalp-lifting, relaxed open-mouth, silent bared-teeth, open-mouth silent bared-teeth displays and finally the open-mo ...200717303940
prolonged effects of intra-nasally administered testosterone on proceptive behavior in female capuchin monkeys (cebus apella).sexual dysfunction in the female has been associated with a decrease in androgen levels, which can be reversed by testosterone treatment, however, bearing the risk of adverse side effects. previously we found that intranasal application of testosterone led to an increase in proceptive behavior in female capuchin monkeys, which was still enhanced beyond treatment pointing to prolonged effects. here, we sought to replicate our previous findings and to further examine possible prolonged effects of ...200717306379
perineal urethrostomy in a brown capuchin monkey (cebus apella).a 14-yr-old male brown capuchin monkey (cebus apella) was presented to the veterinary teaching hospital of the hebrew university of jerusalem, israel, with stranguria. the history included distal urethral obstruction and a previous surgical attempt to create a urinary diversion through the perineum. a perineal urethrostomy was performed. in a 17-mo follow-up period, neither stranguria nor dysuria was observed, and the monkey's social behavior appeared normal. perineal urethrostomy appears to be ...200617312810
ocelot (leopardus pardalis) predation on primates in caratinga biological station, southeast brazil.this study demonstrates that ocelots (leopardus pardalis) extensively use primates as a food resource at the caratinga biological station (cbs) in southeast brazil. analysis of 60 fecal samples collected over 4 years revealed predation upon the brown howler monkey (alouatta guariba), the muriqui (brachyteles hypoxanthus), and the brown capuchin monkey (cebus apella). the most frequent items found in the fecal samples analyzed were calomys (n=16) and non-identified aves (n=15), followed by a. gua ...200717330310
token mediated tool exchange between tufted capuchin monkeys (cebus apella).three experiments were conducted to test whether a pair of tufted capuchin monkeys (cebus apella) could generalize their ability to exchange tokens and tool objects with a human experimenter to similar exchanges with a conspecific partner. monkeys were tested in side-by-side enclosures, one enclosure containing a tool-use apparatus and one or more token(s), and the other enclosure containing one or more tool object(s). the monkeys willingly transferred tokens and tools to a conspecific with litt ...200717345056
a comparative study of cytoarchitecture and serotonergic afferents in the suprachiasmatic nucleus of primates (cebus apella and callithrix jacchus) and rats (wistar and long evans strains).the suprachiasmatic nucleus, an essential diencephalic component of the circadian timing system, plays a role in the generation and modulation of behavioral and neuroendocrine rhythms in mammals. its cytoarchitecture, neurochemical and hodological characteristics have been investigated in various mammalian species, particularly in rodents. in most species, two subdivisions, based on these aspects and considered to reflect functional specialization within the nucleus, can be recognized. many stud ...200717382302
exploring the relationship between cerebellar asymmetry and handedness in chimpanzees (pan troglodytes) and capuchins (cebus apella).a comparative study of chimpanzee (pan troglodytes) and capuchin monkey (cebus apella) cerebellar asymmetry and its relationship to handedness was conducted. magnetic resonance images of the brain and behavioral data on a coordinated bimanual task were obtained from 16 chimpanzees and 11 capuchins. chimpanzees displayed a greater rightward bias of the posterior cerebellum and capuchins displayed a greater leftward bias of the anterior cerebellum. cerebellar asymmetries were significantly associa ...200717382360
progesterone, but not luteal estrogen, is required for the establishment of pregnancy in the new world monkey cebus apella.the aim of this study was to examine the requirement of luteal progesterone or luteal estrogen for the establishment of pregnancy in the cebus monkey and to test in a primate species the synergism between ru 486 and letrozole (ltz) found in rodents for inhibiting implantation. exposure of target tissues to either hormone was suppressed during the mid-luteal phase of mating cycles by subcutaneous administration of the antiprogestin (ru 486), the aromatase inhibitor ltz or the antiestrogen (ici 18 ...200717387700
cerebral petalias and their relationship to handedness in capuchin monkeys (cebus apella).cerebral asymmetries are thought to be associated with increased hemispheric specialization of function. we investigated cerebral petalias, the protrusion of one cerebral hemisphere relative to the other, and their relationship to lateralized behavior in capuchin monkeys (cebus apella). magnetic resonance images of the brain and behavioral data on a coordinated bimanual task were obtained from 13 capuchins. while a significant population-level left-frontal petalia was found, this was not related ...200717418285
experimental evidence for route integration and strategic planning in wild capuchin monkeys.both in captivity and the wild, primates are found to travel mostly to the nearest available resource, but they may skip over the closest resource and travel to more distant resources, which are often found to be more productive. this study examines the tradeoff between distance and reward in the foraging choices of one group of wild capuchin monkeys (cebus apella nigritus) using feeding platforms in large-scale foraging experiments conducted over four years. three feeding sites were arrayed in ...200717464518
pattern recognition in tufted capuchin monkeys (cebus apella): the role of the spatial organisation of stimulus parts.we report four experiments aimed at characterising the role played by the encoding of the spatial relationship between stimulus parts in pattern recognition in capuchin monkeys, as assessed by a matching to sample task. the results of the first experiment, which were also reliably replicated at different stages in the course of the study, indicated that the simultaneous rotation and/or translation of the four parts into which the stimuli were divided, but not a global rotation of the entire stim ...200717467068
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 ...200817549530
perception of the müller-lyer illusion in capuchin monkeys (cebus apella).visual illusions are formed by differences between the perception of one figure and its real physical characteristics. the müller-lyer illusion is the best known and most studied geometric illusion, consisting in the subject's judgment between two parallel lines that have the same size, one flanked with outward-pointing arrowheads, and the other with inward-pointing arrowheads. these arrowheads act as inductors that make the lines to be perceived as having different sizes, inward-pointing stimul ...200717586063
circadian cortisol secretion and circadian adrenal responses to acth are maintained in dexamethasone suppressed capuchin monkeys (cebus apella).we tested the hypothesis that the capuchin monkey adrenal (cebus apella) gland has oscillatory properties that are independent of adrenocorticotropic hormone (acth) by exploring under acth suppression by dexamethasone: (i) maintenance of a circadian rhythm of plasma cortisol and (ii) clock time dependency of plasma cortisol response to exogenous acth. the capuchin monkey had a clear acth and plasma cortisol rhythm. dexamethasone treatment resulted in low non-rhythmic acth levels and decreased co ...200817620278
scaling of neuron number and volume of the pulvinar complex in new world primates: comparisons with humans, other primates, and mammals.the lateral posterior nucleus and pulvinar (lp-pulvinar complex) are the principal thalamic nuclei associated with the elaborate development of the dorsal and ventral streams of the parietal cortex in primates. in humans, a novel site of origin for a subpopulation of pulvinar neurons has been observed, the ganglionic eminence of the telencephalon. this additional site of neuron origin has been proposed to contribute to the pulvinar's evolutionary expansion (letinic and rakic [2001] nat neurosci ...200717640049
lu 35-138 ((+)-(s)-3-{1-[2-(1-acetyl-2,3-dihydro-1h-indol-3-yl)ethyl]-3,6-dihydro-2h-pyridin-4-yl}-6-chloro-1h-indole), a dopamine d4 receptor antagonist and serotonin reuptake inhibitor: characterisation of its in vitro profile and pre-clinical antipsychotic potential.the present study describes the pharmacological profile of the putative antipsychotic drug lu 35-138 ((+)-(s)-3-{1-[2-(1-acetyl-2,3-dihydro-1h-indol-3-yl)ethyl]-3,6-dihydro-2h-pyridin-4-yl}-6-chloro-1h-indole). the in vitro receptor profile of lu 35-138 revealed high affinity (k(i)=5 nm) and competitive antagonism (k(b)=8 nm) at dopamine d(4) receptors combined with potent 5-ht uptake inhibition (ic(50)=3.2 nm) and moderate alpha(1)-adrenoceptor affinity (k(i)=45 nm). in vivo, lu 35-138 selectiv ...200717689529
repellent efficacy of formic acid and the abdominal secretion of carpenter ants (hymenoptera: formicidae) against amblyomma ticks (acari: ixodidae).formic acid is a substance produced by some ants for defense, trail marking, and recruitment. some animals are known to rub ants or other arthropods on parts of their plumage or fur to anoint themselves with released substances. a recent study with a semifree-ranging group of capuchin monkeys, cebus apella l., in the tietê ecological park, sao paulo, brazil, an area of occurrence of the tick species amblyomma cajennense (f.), revealed that "anting" with carpenter ants, camponotus rufipes f. (hym ...200717695031
do capuchin monkeys (cebus apella) use tokens as symbols?in the absence of language, the comprehension of symbols is difficult to demonstrate. tokens can be considered symbols since they arbitrarily stand for something else without having any iconic relation to their referent. we assessed whether capuchin monkeys (cebus apella) can use tokens as symbols to represent and combine quantities. our paradigm involved choices between various combinations of tokens a and b, worth one and three rewards, respectively. pay-off maximization required the assessmen ...200717698487
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 ...200817708538
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 ...200817719190
mineral trioxide aggregate as a root canal filling material in reimplanted teeth. microscopic analysis in monkeys.this study analyzed mineral trioxide aggregate (mta) as a root canal filling material for the immediate reimplantation of monkey teeth. four adult capuchin monkeys cebus apella were used, which had their maxillary and mandibular lateral incisors on both sides extracted and reimplanted after 15 min. during the extra-alveolar period, the teeth were kept in saline solution and after reimplantation retention was performed with a stainless steel wire and composite resin for 14 days. after 7 days, the ...200717803482
summation and quantity judgments of sequentially presented sets by capuchin monkeys (cebus apella).capuchin monkeys (cebus apella) were presented with two sets of food items, identical in food type but differing in number. animals selected one set and were permitted to consume their choice. set sizes ranged from 1 to 6 items. in experiment 1, each set was uncovered and recovered before a response was made, and the monkeys selected the larger set at high levels. experiment 2 presented sets that had both visible and nonvisible food items in them at the time of the response, thus requiring the m ...200817879377
allonursing in tufted capuchin monkeys (cebus nigritus): milk or pacifier?allonursing, the behaviour of females nursing offspring that are not their own, is relatively frequent in capuchin monkeys. using focal-animal sampling and ad libitum observations we describe the pattern of allonursing in a wild group of tufted capuchins, cebus nigritus (4 cohorts, 22 infants), at iguazú national park, north-eastern argentina, and test several hypotheses on the adaptive value of allonursing. during 2,351 contact hours with the group (including 4,207 focal-animal samples totalizi ...200817893441
consistency of hand preference across low-level and high-level tasks in capuchin monkeys (cebus apella).numerous studies investigating behavioral lateralization in capuchins have been published. although some research groups have reported a population-level hand preference, other researchers have argued that capuchins do not show hand preference at the population level. as task complexity influences the expression of handedness in other primate species, the purpose of this study was to collect hand preference data across a variety of high- and low-level tasks to evaluate how task complexity influe ...200817894405
food and token quantity discrimination in capuchin monkeys (cebus apella).quantity discrimination is adaptive in a variety of ecological contexts and different taxa discriminate stimuli differing in numerousness, both in the wild and in laboratory settings. quantity discrimination between object arrays has been suggested to be more demanding than between food arrays but, to our knowledge, the same paradigm has never been used to directly compare them. we investigated to what extent capuchin monkeys' relative numerousness judgments (rnjs) with food and token are alike. ...200817901990
food variety-seeking in tufted capuchin monkeys (cebus apella).variety-seeking is a central issue to consumer behaviour research and a phenomenon of crucial relevance, both for human and animal nutrition. variety-seeking increases the probability of nutrient adequacy in omnivores, and in humans it may also contribute to obesity epidemic by diversifying food selection and leading to excessive food intake. although variety-seeking has been extensively investigated in humans, little is known about most of the factors shaping variety-seeking in other species. c ...200817904595
ultrasonographic imaging of the reproductive tract and surgical recovery of oocytes in cebus apella (capuchin monkeys).two-dimensional real-time and doppler ultrasonography are valuable non-invasive methods to assess reproductive anatomy and physiology. in adult, postpubertal female cebus apella (capuchin monkeys), the objectives were to determine (1) uterine and ovarian dimensions, ovarian follicular dynamics, day of ovulation, and arterial blood flow of uterus and utero-ovarian ligament during the follicular phase of the menstrual cycle and (2) the number of oocytes aspirated from antral follicles at laparotom ...200717915305
copying without rewards: socially influenced foraging decisions among brown capuchin monkeys.an individual's foraging activity can be influenced by the choices made by nearby conspecifics. the interest shown in the location and characteristics of a feeding patch may depend on the feeding success of a conspecific there, a process that needs to be distinguished from choices guided by rewards to the observer itself. we investigated how rewards for both self and others influence the foraging choices of captive capuchin monkeys (cebus apella). thirteen adult capuchins observed familiar femal ...200717929373
observational learning from tool using models by human-reared and mother-reared capuchin monkeys (cebus apella).studies of wild capuchins suggest an important role for social learning, but experiments with captive subjects have generally not supported this. here we report social learning in two quite different populations of capuchin monkeys (cebus apella). in experiment 1, human-raised monkeys observed a familiar human model open a foraging box using a tool in one of two alternative ways: levering versus poking. in experiment 2, mother-raised monkeys viewed similar techniques demonstrated by monkey model ...200817968602
social diffusion of novel foraging methods in brown capuchin monkeys (cebus apella).it has been reported that wild capuchin monkeys exhibit several group-specific behavioural traditions. by contrast, experiments have found little evidence for the social learning assumed necessary to support such traditions. the present study used a diffusion chain paradigm to investigate whether a novel foraging task could be observationally learned by capuchins (cebus apella) and then transmitted along a chain of individuals. we used a two-action paradigm to control for independent learning. e ...200817971322
inequity responses of monkeys modified by effort.without joint benefits, joint actions could never have evolved. cooperative animals need to monitor closely how large a share they receive relative to their investment toward collective goals. this work documents the sensitivity to reward division in brown, or tufted, capuchin monkeys (cebus apella). in addition to confirming previous results with a larger subject pool, this work rules out several alternative explanations and adds data on effort sensitivity. thirteen adult monkeys exchanged toke ...200718000045
evidence of reciprocal connections between the dorsal raphe nucleus and the retina in the monkey cebus apella.possible connections between the retina and the raphe nuclei were investigated in the monkey cebus apella by intraocular injection of cholera toxin b subunit (ctb). ctb-positive fibers were seen in the lateral region of the dorsal raphe nucleus (dr) on the side contralateral to the injection, and a few labeled perikarya were observed in the lateral portion of the dr on the ipsilateral side. our findings suggest that direct and reciprocal connections between the retina and dr may exist in cebus a ...200818079059
generalization hypothesis of abstract-concept learning: learning strategies and related issues in macaca mulatta, cebus apella, and columba livia.the generalization hypothesis of abstract-concept learning was tested with a meta-analysis of rhesus monkeys (macaca mulatta), capuchin monkeys (cebus apella), and pigeons (columba livia) learning a same/different (s/d) task with expanding training sets. the generalization hypothesis states that as the number of training items increases, generalization from the training pairs will increase and could explain the subjects' accurate novel-stimulus transfer. by contrast, concept learning is learning ...200718085922
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 ...200818155128
effects of cyclosporin, phenytoin, and nifedipine on the synthesis and degradation of gingival collagen in tufted capuchin monkeys (cebus apella): histochemical and mmp-1 and -2 and collagen i gene expression analyses.the purpose of this experimental study was to evaluate the collagen fiber distribution histologically after phenytoin, cyclosporin, or nifedipine therapy and to correlate it with collagen i and matrix metalloproteinase (mmp)-1 and -2 gene expression levels.200818166100
an experimental analysis of ingestion rates in an omnivorous species.food intake is difficult to estimate under natural conditions. we investigated ingestion rates of 14 different food types in 26 captive capuchin monkeys (cebus apella). the procedure consisted in weighing a piece of food and using a two alternative choice tests to present food to the subject, alone in its cage. we recorded the food chosen and the time it took the subject to consume the food entirely. consumption time was converted into ingestion rates (g/s) for each food type. ingestion rates of ...200818186073
scream-embrace displays in wild black-horned capuchin monkeys.reintroduction of capuchin monkeys (cebus apella) into their social group in captivity can elicit sirena screams and embraces. captive scream-embrace displays are male biased, and females never perform sirena screams. one hypothesis is that scream-embrace displays serve a tension-reduction or reconciliatory function between males with conflicting interests. alternatively, these displays may function to maintain strong affiliative bonds between friendly male dyads. scream and/or embrace displays ...200818186458
blood biochemical indicators in young and adult cebus apella of both sexes.a frequent drawback in physiology of non-human primates is that normal values for a variety of indicators (haematological, biochemical and others) are scant.200818199067
hematological and plasma biochemical values for captive tufted capuchin monkeys (cebus apella).hematological and blood biochemical parameters are of great importance in medical and veterinary practice. unfortunately, normal reference range intervals for hematological and serum biochemical values in the tufted capuchin monkey (cebus apella) have seldom been reported. the study reported here is based on data from blood samples collected from 44 monkeys over an 8-year period. male and female data are displayed separately within two age categories: juveniles and adults, and effects for sex an ...200818203147
infanticide in black capuchin monkeys (cebus apella nigritus) in iguazú national park, argentina.we report here one observed and two potential cases of infanticide during a brief period of 1 month after a dominant male replacement in one group of black capuchin monkeys in iguazú national park, argentina. we also compile infant disappearances and demographic data in seven groups followed from 1-14 years. behavioral and molecular data showed that the probability that an infanticidal male would kill his own progeny is very low in this species. females that lost infants less than 6 months old h ...200818236410
monkeys (macaca mulatta and cebus apella) track, enumerate, and compare multiple sets of moving items.despite many demonstrations of numerical competence in nonhuman animals, little is known about how well animals enumerate moving stimuli. in this series of experiments, rhesus monkeys (macaca mulatta) and capuchin monkeys (cebus apella) performed computerized tasks in which they had to enumerate sets of stimuli. in experiment 1, rhesus monkeys compared two sets of moving stimuli. experiment 2 required comparisons of a moving set and a static set. experiment 3 included human participants and capu ...200818248115
reversible medetomidine/ketamine anesthesia in captive capuchin monkeys (cebus apella).medetomidine, an alpha(2)-adrenergic receptor agonist administered with ketamine, induces sedation/anesthesia in non-human primates in a dose-dependent, species-specific manner.200818269533
ordinal judgments of symbolic stimuli by capuchin monkeys (cebus apella) and rhesus monkeys (macaca mulatta): the effects of differential and nondifferential reward.ordinal learning was investigated in capuchin monkeys (cebus apella) and rhesus monkeys (macaca mulatta). in experiment 1, both species were presented with pairings of the arabic numerals 0 to 9. some monkeys were given food rewards equal to the value of the numeral selected and some were rewarded with a single pellet only for choosing the higher numeral within the pair. both species learned to select the larger numeral, but only rhesus monkeys that were differentially rewarded performed above c ...200818298281
associations between primates and other mammals in a central amazonian forest landscape.little information exists on mixed-species groups between primates and other mammals in neotropical forests. in this paper, we describe three such associations observed during an extensive large-vertebrate survey in central amazonia, brazil. mixed-species groups between a primate species and another mammal were observed on seven occasions between squirrel monkeys (saimiri cf. ustus) and either south american coatis (nasua nasua) or tayras (eira barbara) and between brown capuchins (cebus apella) ...200818306981
learning from others' mistakes in capuchin monkeys (cebus apella).we investigated whether tufted capuchin monkeys (cebus apella) learn from others' mistakes. we prepared three kinds of transparent containers having the same appearance: one that could be opened by the lid, one that could be opened from the bottom, and one that could be opened either way. using each of the first two one-way-open type containers, the monkeys were trained to copy the human demonstrator's action to open the container and obtain a piece of sweet potato contained therein. after this ...200818320243
distribution of neurofilament proteins in the lateral geniculate nucleus, primary visual cortex, and area mt of adult cebus monkeys.we investigated the distribution pattern of smi-32-immunopositive cells in the lateral geniculate nucleus (lgn) and in the primary (v1) and middle temporal (mt) cortical visual areas of the adult new world monkey cebus apella. in the lgn, the reaction for smi-32 labeled cells in both the magnocellular (m) and parvocellular (p) layers. however, the cellular label was heavier in m layers, which also showed a more intense labeling in the neuropil. in v1, the reaction showed a lamination pattern, wi ...200818383052
reference values for selected ophthalmic diagnostic tests of the capuchin monkey (cebus apella).to perform selected ophthalmic diagnostic tests in healthy capuchin monkeys (cebus apella) with the aim of establishing normal physiological reference values for this species.200818435663
[trichophyton simii in a "caí" monkey (cebus apella) colony in the province of corrientes, argentina.].the objective is to describe an outbreak of trichophyton simii in a cebus apella monkey colony in argentine. during summer, alopecic zones appeared on dorsal regions from head to base of the tail of the animals. the hair and skin of nine animals were streaked onto sabouraud dextrose with cloramphenicol and incubated at 25 degrees c. by the 10th day, white, filamentous colonies, which turned pale pink, developed from simples of four animals. microscopical examinations were carried out and, becaus ...199818473523
inferences about the location of food in capuchin monkeys (cebus apella) in two sensory modalities.the authors tested the ability of capuchin monkeys (cebus apella) to make inferences about hidden food. in experiment 1, we showed the content of 2 boxes, 1 of which was baited (visual condition, vc) or we shook both boxes producing noise from the baited box (auditory condition, ac). seven subjects (out of 8) were above chance in the vc, whereas only 1 was above chance in ac. during treatment, by manipulating empty and filled objects subjects experienced the relation between noise and content. w ...200818489231
analogical reasoning in a capuchin monkey (cebus apella).previous evidence has suggested that analogical reasoning (recognizing similarities among object relations when the objects themselves are dissimilar) is limited to humans and apes. this study investigated whether capuchin monkeys (cebus apella) can use analogical reasoning to solve a 3-dimensional search task. the task involved hiding a food item under 1 of 2 or 3 plastic cups of different sizes and then allowing subjects to search for food hidden under the cup of analogous size in their own se ...200818489232
attending to the outcome of others: disadvantageous inequity aversion in male capuchin monkeys (cebus apella).brosnan and de waal [nature 425:297-299, 2003] reported that capuchin monkeys responded negatively to unequal reward distributions between themselves and another individual when comparing their own rewards with that of their partner. it was suggested that social emotions provided the underlying motivation for such behavior and that this inequity aversion is specific to the social domain. however, alternative hypotheses such as the "frustration effect" or the "food expectation hypothesis" may pro ...200818521838
an efficient computerized testing method for the capuchin monkey (cebus apella): adaptation of the lrc-cts to a socially housed nonhuman primate species.even with advances in automated testing techniques, the capuchin monkey (cebus apella) can be a difficult species to test in the laboratory, given its social/behavioral tendencies and typical activity pattern. laboratories that maintain social colonies of capuchin monkeys are able to separate and test individuals, but the process can be very effortful and time consuming, and the resulting data can be modest in quantity. the present article describes procedures and apparatuses that were used to t ...200818522071
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. ...200818545670
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 ...200918574604
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 ...200818594798
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 ...200818598400
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 ...200818620330
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 ...200818626908
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 ...200818668302
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 ...200918670794
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: ...200818696009
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, ...200918712532
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 ...200818757730
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 ...200918759195
[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 ...200818767561
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 ...200818785631
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 ...200818805494
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 ...200818809203
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 ...200818812309
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 ...200818824860
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 ...200818840573
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 ...200918850586
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