Showing papers on "Primate published in 2011"

Cross-Species Transmission of a Novel Adenovirus Associated with a Fulminant Pneumonia Outbreak in a New World Monkey Colony

Abstract: Adenoviruses are DNA viruses that naturally infect many vertebrates, including humans and monkeys, and cause a wide range of clinical illnesses in humans Infection from individual strains has conventionally been thought to be species-specific Here we applied the Virochip, a pan-viral microarray, to identify a novel adenovirus (TMAdV, titi monkey adenovirus) as the cause of a deadly outbreak in a closed colony of New World monkeys (titi monkeys; Callicebus cupreus) at the California National Primate Research Center (CNPRC) Among 65 titi monkeys housed in a building, 23 (34%) developed upper respiratory symptoms that progressed to fulminant pneumonia and hepatitis, and 19 of 23 monkeys, or 83% of those infected, died or were humanely euthanized Whole-genome sequencing of TMAdV revealed that this adenovirus is a new species and highly divergent, sharing <57% pairwise nucleotide identity with other adenoviruses Cultivation of TMAdV was successful in a human A549 lung adenocarcinoma cell line, but not in primary or established monkey kidney cells At the onset of the outbreak, the researcher in closest contact with the monkeys developed an acute respiratory illness, with symptoms persisting for 4 weeks, and had a convalescent serum sample seropositive for TMAdV A clinically ill family member, despite having no contact with the CNPRC, also tested positive, and screening of a set of 81 random adult blood donors from the Western United States detected TMAdV-specific neutralizing antibodies in 2 individuals (2/81, or 25%) These findings raise the possibility of zoonotic infection by TMAdV and human-to-human transmission of the virus in the population Given the unusually high case fatality rate from the outbreak (83%), it is unlikely that titi monkeys are the native host species for TMAdV, and the natural reservoir of the virus is still unknown The discovery of TMAdV, a novel adenovirus with the capacity to infect both monkeys and humans, suggests that adenoviruses should be monitored closely as potential causes of cross-species outbreaks

Primate Prefrontal Cortex Evolution: Human Brains Are the Extreme of a Lateralized Ape Trend

Abstract: The prefrontal cortex is commonly associated with cognitive capacities related to human uniqueness: purposeful actions towards higher-level goals, complex social information processing, introspection, and language. Comparative investigations of the prefrontal cortex may thus shed more light on the neural underpinnings of what makes us human. Using histological data from 19 anthropoid primate species (6 apes including humans and 13 monkeys), we investigate cross-species relative size changes along the anterior (prefrontal) and posterior (motor) axes of the cytoarchitectonically defined frontal lobe in both hemispheres. Results reveal different scaling coefficients in the left versus right prefrontal hemisphere, suggest that the primary factor underlying the evolution of primate brain architecture is left hemispheric prefrontal hyperscaling, and indicate that humans are the extreme of a left prefrontal ape specialization in relative white to grey matter volume. These results demonstrate a neural adaptive shift distinguishing the ape from the monkey radiation possibly related to a cognitive grade shift between (great) apes and other primates.

Macaque cytochromes P450: nomenclature, transcript, gene, genomic structure, and function.

Abstract: Monkeys, especially macaques, including cynomolgus (Macaca fascicularis) and rhesus monkeys (Macaca mulatta), are frequently used in drug metabolism studies due to their evolutionary closeness to humans. Recently, numerous cytochrome P450 (P450 or CYP) cDNAs have been identified and characterized in cynomolgus and rhesus monkeys and were named by the P450 Nomenclature Committee. However, recent advances in genome analysis of cynomolgus and rhesus monkeys revealed that some monkey P450s are apparently orthologous to human P450s and thus need to be renamed corresponding to their human orthologs. In this review, we focus on the P450s identified in cynomolgus and rhesus monkeys and present an overview of the identity and functional characteristics of each P450 cDNA in the CYP1-4 families. Information on the Japanese monkey (Macaca fuscata), African green monkey (Cercopithecus aethiops), and marmoset (Callithrix jacchus), primate species used in some drug metabolism studies, are also included. We compared the ...

The development of small primate models for aging research.

Abstract: Nonhuman primate (NHP) aging research has traditionally relied mainly on the rhesus macaque. But the long lifespan, low reproductive rate, and relatively large body size of macaques and related Old World monkeys make them less than ideal models for aging research. Manifold advantages would attend the use of smaller, more rapidly developing, shorter-lived NHP species in aging studies, not the least of which are lower cost and the ability to do shorter research projects. Arbitrarily defining "small" primates as those weighing less than 500 g, we assess small, relatively short-lived species among the prosimians and callitrichids for suitability as models for human aging research. Using the criteria of availability, knowledge about (and ease of) maintenance, the possibility of genetic manipulation (a hallmark of 21st century biology), and similarities to humans in the physiology of age-related changes, we suggest three species--two prosimians (Microcebus murinus and Galago senegalensis) and one New World monkey (Callithrix jacchus)--that deserve scrutiny for development as major NHP models for aging studies. We discuss one other New World monkey group, Cebus spp., that might also be an effective NHP model of aging as these species are longer-lived for their body size than any primate except humans.

Patterns of mineral lick visitation by spider monkeys and howler monkeys in Amazonia: are licks perceived as risky areas?

Abstract: Mineral licks—also known as “salados,” “saladeros,” or “collpas”—are specific sites in tropical and temperate ecosystems where a large diversity of mammals and birds come regularly to feed on soil. Although the reasons for vertebrate geophagy are not completely understood, animals are argued to obtain a variety of nutritional and health benefits from the ingestion of soil at mineral licks. We studied the temporal patterns of mineral lick use by white-bellied spider monkey (Ateles belzebuth) and red howler monkey (Alouatta seniculus) in a lowland rain forest in Amazonian Ecuador. Using camera and video traps at four different mineral licks, combined with behavioral follows of one group of spider monkeys, we documented rates of mineral lick visitation by both primate species and the relative frequency and intensity of mineral lick use by spider monkeys. On the basis of 1,612 days and 888 nights of mineral lick monitoring, we found that A. belzebuth and A. seniculus both visit mineral licks frequently throughout the year (on average ∼14% of days for both species), and mineral lick visitation was influenced by short-term environmental conditions (e.g. sunny and dry weather). For spider monkeys, the area surrounding the lick was also the most frequently and most intensively used region within the group's home range. The fact that spider monkeys spent long periods at the lick area before coming to the ground to obtain soil, and the fact that both species visited the lick preferentially during dry sunny conditions (when predator detectability is presumed to be relatively high) and visited simultaneously more often than expected by chance, together suggest that licks are indeed perceived as risky areas by these primates. We suggest that howler and spider monkeys employ behavioral strategies aimed at minimizing the probability of predation while visiting the forest floor at risky mineral lick sites. Am. J. Primatol. 73:386–396, 2011. © 2010 Wiley-Liss, Inc.

Influence of the landscape matrix on the abundance of arboreal primates in fragmented landscapes

Abstract: Composition of the landscape matrix of surrounding forest fragments is thought to be critically important to the survival of arboreal primates because it offers structures that help the animals move between fragments and other foraging sites. However, little is known about the composition of the matrix used by these animals. The aim of this study was to quantitatively assess the importance of the landscape matrix and its effects on primate abundance, using black howler monkeys (Alouatta pigra) living in a landscape fragmented by the expansion of agriculture and pastures for livestock in southeastern Mexico. In 2008, a complete census of the monkeys was carried out across the 2000-ha landscape matrix, and for every site where we observed monkeys, we recorded canopy height, tree basal area, food-source abundance, and distance to the nearest fragment. A total of 244 howler monkeys, distributed among 48 groups (including six solitary males) were counted in the matrix. Mean troop size was 5.6 ± 2.8 individuals, and the mode was three individuals. The highest number of troops and greatest howler monkey abundance were recorded in the isolated trees, the eucalyptus plantation, and orchards. A generalized linear model revealed that monkey abundance tended to be higher in matrix elements with higher canopy height, greater food availability, and closest to rainforest fragments. These results suggest that it is necessary to take into account the many elements of the landscape when drawing up conservation and habitat management plans, particularly in order to establish connectivity among the fragments and elements of the matrix with native trees.

Primate population dynamics over 32.9 years at Ngogo, Kibale National Park, Uganda.

Abstract: We present census data for eight primate species spanning 32.9 years along the same transect at Ngogo, Kibale National Park, Uganda, demonstrating major changes in the composition of the primate community. Correlated with an estimated decline of ∼89% in the red colobus population was an increase in encounter rates with chimpanzee parties. Our data, along with the unusually high rates of predation by chimpanzees on red colobus at Ngogo and the fact that the chimpanzee community at Ngogo is the largest ever recorded, support the conclusion that the red colobus decline was caused primarily by chimpanzee predation. This seems to be the first documented case of predation by one nonhuman primate causing the population decline in another. We evaluated disease and interspecific competition as other possible causes of the red colobus decline, but judged them to be relatively insignificant compared with predation by chimpanzees. Notable changes in encounter rates with other primate species may have resulted from forest expansion. Those for mangabeys, redtails, and black and white colobus increased significantly. Encounter rates increased for l'Hoest's monkeys too, but the increased sightings may have been an artifact of increased habituation. Sightings of blue monkey and baboon groups declined. There was no significant change in encounter rates for all species combined. The Ngogo primate community seemed to be in a nonequilibrium state, changing from one dominated by two species, a folivore (red colobus) and a frugivorous omnivore (redtails), to one dominated by three species of frugivorous omnivores (redtails, mangabeys, and chimpanzees). This study demonstrates the importance of long-term monitoring in understanding population dynamics and the role of intrinsic variables in shaping the species composition of a community. Am. J. Primatol. 73:997–1011, 2011. © 2011 Wiley-Liss, Inc.

Impact of intrasexual selection on sexual dimorphism and testes size in the Mexican howler monkeys Alouatta palliata and A. pigra

Abstract: One of the goals of physical anthropology and primatology is to understand how primate social sys- tems influence the evolution of sexually selected traits. Howler monkeys provide a good model for studying sex- ual selection due to differences in social systems between related species. Here, we examine data from the sister howler monkey species Alouatta palliata and A. pigra inhabiting southeastern Mexico and northern Guatemala. We use a resampling approach to analyze differences in sexual dimorphism of body and canine size. In addition, we compare testes size as a way of gauging the intensity of sperm competition in both species. Morphometric data were collected from wild-caught individuals, including body mass and length, and dental data were obtained from casts from wild individuals and from museum speci- mens. Although A. pigra individuals are larger than their A. palliata counterparts, we find that both species exhibit similar levels of sexual dimorphism for all of the variables considered. Testicular volume results indicate that A. pal- liata male testes are on average twice as large as those of A. pigra males, suggesting more intense sperm competi- tion in the former species. Our study shows that A. pigra is not highly sexually dimorphic as was once thought, and testes size differences suggest the need for a clearer understanding of howler monkey social systems. Am J Phys Anthropol 146:179-187, 2011. V C 2011 Wiley-Liss, Inc.

The TRIM5 Gene Modulates Penile Mucosal Acquisition of Simian Immunodeficiency Virus in Rhesus Monkeys

Abstract: There is considerable variability in host susceptibility to human immunodeficiency virus type 1 (HIV-1) infection, but the host genetic determinants of that variability are not well understood. In addition to serving as a block for cross-species retroviral infection, TRIM5 was recently shown to play a central role in limiting primate immunodeficiency virus replication. We hypothesized that TRIM5 may also contribute to susceptibility to mucosal acquisition of simian immunodeficiency virus (SIV) in rhesus monkeys. We explored this hypothesis by establishing 3 cohorts of Indian-origin rhesus monkeys with different TRIM5 genotypes: homozygous restrictive, heterozygous permissive, and homozygous permissive. We then evaluated the effect of TRIM5 genotype on the penile transmission of SIVsmE660. We observed a significant effect of TRIM5 genotype on mucosal SIVsmE660 acquisition in that no SIV transmission occurred in monkeys with only restrictive TRIM5 alleles. In contrast, systemic SIV infections were initiated after preputial pocket exposures in monkeys that had at least one permissive TRIM5 allele. These data demonstrate that host genetic factors can play a critical role in restricting mucosal transmission of a primate immunodeficiency virus. In addition, we used our understanding of TRIM5 to establish a novel nonhuman primate penile transmission model for AIDS mucosal pathogenesis and vaccine research.

Primates of West Africa : a field guide and natural history

Abstract: West Africa, from the coast of Senegal to Lake Chad and Cameroon's Sanaga River, is home to 60 primate species and subspecies, 46 of which occur nowhere else. They range from the nocturnal angwantibo, pottos, and galagos, to the mangabeys, baboons, and the drill, to guenons and colobus monkeys. In addition, no less than three of the great apes are restricted to this region, including two chimpanzees and the Cross River gorilla. This comprehensive guide provides a brief introduction to the region, its topography, climate, vegetation, native peoples and history, and includes as well essays on the classification and evolutionary history of the region's primates, and a review of conservation activities and primate field research projects since the 1960s. The bulk of the book is dedicated to accounts for each primate species and subspecies, providing information not only on their identifying features and geographic distributions, but also on their natural history -- their populations and habitats, locomotion, vocalizations, activity patterns, diets and feeding, ranging, and social behaviors.

Rhesus Monkeys See Who They Hear: Spontaneous Cross-Modal Memory for Familiar Conspecifics

Abstract: Rhesus monkeys gather much of their knowledge of the social world through visual input and may preferentially represent this knowledge in the visual modality. Recognition of familiar faces is clearly advantageous, and the flexibility and utility of primate social memory would be greatly enhanced if visual memories could be accessed cross-modally either by visual or auditory stimulation. Such cross-modal access to visual memory would facilitate flexible retrieval of the knowledge necessary for adaptive social behavior. We tested whether rhesus monkeys have cross-modal access to visual memory for familiar conspecifics using a delayed matching-to-sample procedure. Monkeys learned visual matching of video clips of familiar individuals to photographs of those individuals, and generalized performance to novel videos. In crossmodal probe trials, coo-calls were played during the memory interval. The calls were either from the monkey just seen in the sample video clip or from a different familiar monkey. Even though the monkeys were trained exclusively in visual matching, the calls influenced choice by causing an increase in the proportion of errors to the picture of the monkey whose voice was heard on incongruent trials. This result demonstrates spontaneous cross-modal recognition. It also shows that viewing videos of familiar monkeys activates naturally formed memories of real monkeys, validating the use of video stimuli in studies of social cognition in monkeys.

Tail growth tracks the ontogeny of prehensile tail use in capuchin monkeys (Cebus albifrons and C. apella)

Abstract: Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH 44272KEY WORDS tails; growth; bending strengthABSTRACT Physical anthropologists have devotedconsiderable attention to the structure and function ofthe primate prehensile tail. Nevertheless, previous mor-phological studies have concentrated solely on adults, de-spite behavioral evidence that among many primatetaxa, including capuchin monkeys, infants and juvenilesuse their prehensile tails during a greater number andgreater variety of positional behaviors than do adults. Inthis study, we track caudal vertebral growth in a mixedlongitudinal sample of white-fronted and brown capu-chin monkeys (Cebus albifrons and Cebus apella). Wehypothesized that young capuchins would have relativelyrobust caudal vertebrae, affording them greater tailstrength for more frequent tail-suspension behaviors.Our results supported this hypothesis. Caudal vertebralbending strength (measured as polar section modulus atmidshaft) scaled to body mass with negative allometry,while craniocaudal length scaled to body mass with posi-tive allometry, indicating that infant and juvenile capu-chin monkeys are characterized by particularly strongcaudal vertebrae for their body size. These findings com-plement previous results showing that long bonestrength similarly scales with negative ontogenetic al-lometry in capuchin monkeys and add to a growing bodyof literature documenting the synergy between postcra-nial growth and the changing locomotor demands ofmaturing animals. Although expanded morphometricdata on tail growth and behavioral data on locomotordevelopment are required, the results of this study sug-gest that the adult capuchin prehensile-tail phenotypemay be attributable, at least in part, to selection onjuvenile performance, a possibility that deserves furtherattention. Am J Phys Anthropol 146:465–473, 2011.

Characterization of opsin gene alleles affecting color vision in a wild population of titi monkeys (Callicebus brunneus)

Abstract: The color vision of most platyrrhine primates is determined by alleles at the polymorphic X-linked locus coding for the opsin responsible for the middle- to long-wavelength (M/L) cone photopigment. Females who are heterozygous at the locus have trichromatic vision, whereas homozygous females and all males are dichromatic. This study characterized the opsin alleles in a wild population of the socially monogamous platyrrhine monkey Callicebus brunneus (the brown titi monkey), a primate that an earlier study suggests may possess an unusual number of alleles at this locus and thus may be a subject of special interest in the study of primate color vision. Direct sequencing of regions of the M/L opsin gene using feces-, blood-, and saliva-derived DNA obtained from 14 individuals yielded evidence for the presence of three functionally distinct alleles, corresponding to the most common M/L photopigment variants inferred from a physiological study of cone spectral sensitivity in captive Callicebus.

RESEARCH ARTICLE Characterization of Opsin Gene Alleles Affecting Color Vision in a Wild Population of Titi Monkeys (Callicebus brunneus)

Abstract: The color vision of most platyrrhine primates is determined by alleles at the polymorphic X-linked locus coding for the opsin responsible for the middle- to long-wavelength (M/L) cone photopigment. Females who are heterozygous at the locus have trichromatic vision, whereas homozygous females and all males are dichromatic. This study characterized the opsin alleles in a wild population of the socially monogamous platyrrhine monkey Callicebus brunneus (the brown titi monkey), a primate that an earlier study suggests may possess an unusual number of alleles at this locus and thus may be a subject of special interest in the study of primate color vision. Direct sequencing of regions of the M/L opsin gene using feces-, blood-, and saliva-derived DNA obtained from 14 individuals yielded evidence for the presence of three functionally distinct alleles, corresponding to the most common M/L photopigment variants inferred from a physiological study of cone spectral sensitivity in captive Callicebus. Am. J. Primatol. 73:189–196, 2011. r 2010 Wiley-Liss, Inc.

Cyto-, myelo- and chemoarchitecture of the prefrontal cortex of the Cebus monkey

Abstract: According to several lines of evidence, the great expansion observed in the primate prefrontal cortex (PfC) was accompanied by the emergence of new cortical areas during phylogenetic development. As a consequence, the structural heterogeneity noted in this region of the primate frontal lobe has been associated with diverse behavioral and cognitive functions described in human and non-human primates. A substantial part of this evidence was obtained using Old World monkeys as experimental model; while the PfC of New World monkeys has been poorly studied. In this study, the architecture of the PfC in five capuchin monkeys (Cebus apella) was analyzed based on four different architectonic tools, Nissl and myelin staining, histochemistry using the lectin Wisteria floribunda agglutinin and immunohistochemistry using SMI-32 antibody. Twenty-two architectonic areas in the Cebus PfC were distinguished: areas 8v, 8d, 9d, 12l, 45, 46v, 46d, 46vr and 46dr in the lateral PfC; areas 11l, 11m, 12o, 13l, 13m, 13i, 14r and 14c in the orbitofrontal cortex, with areas 14r and 14c occupying the ventromedial corner; areas 32r, 32c, 25 and 9m in the medial PfC, and area 10 in the frontal pole. This number is significantly higher than the four cytoarchitectonic areas previously recognized in the same species. However, the number and distribution of these areas in Cebus were to a large extent similar to those described in Old World monkeys PfC in more recent studies. The present parcellation of the Cebus PfC considerably modifies the scheme initially proposed for this species but is in line with previous studies on Old World monkeys. Thus, it was observed that the remarkable anatomical similarity between the brains of genera Macaca and Cebus may extend to architectonic aspects. Since monkeys of both genera evolved independently over a long period of time facing different environmental pressures, the similarities in the architectonic maps of PfC in both genera are issues of interest. However, additional data about the connectivity and function of the Cebus PfC are necessary to evaluate the possibility of potential homologies or parallelisms.

Morphological Correlates of the Grooming Claw in Distal Phalanges of Platyrrhines and Other Primates: A Preliminary Study

Abstract: Grooming claws are present on the second pedal digits of strepsirhines and on the second and third pedal digits of tarsiers. However, their presence in New World monkeys is often overlooked. As such, the absence of a grooming claw is generally considered an anthropoid synapomorphy. This study utilizes a quantitative multivariate analysis to define grooming claw morphology and document its presence in platyrrhine monkeys. Our results show that owl monkeys possess grooming claws similar to those of strepsirhines, while titi monkeys possess grooming claw-like morphology. Therefore, we conclude that anthropoids are not clearly united by the absence of a grooming claw. Furthermore, due to their presence in three major primate clades, we infer that it is likely that a grooming claw was present on the second pedal digit of the ancestor of living primates. Therefore, we advise the reassessment of fossil adapids in light of the anatomical correlates described here. This should increase resolution on the homology and polarity of grooming claw morphology, and, therefore, will help provide a sharper picture of primate evolution.

No Evidence for Natural Selection on Endogenous Borna-Like Nucleoprotein Elements after the Divergence of Old World and New World Monkeys

Abstract: Endogenous Borna-like nucleoprotein (EBLNs) elements were recently discovered as non-retroviral RNA virus elements derived from bornavirus in the genomes of various animals. Most of EBLNs appeared to be defective, but some of primate EBLN-1 to -4, which appeared to be originated from four independent integrations of bornavirus nucleoprotein (N) gene, have retained an open reading frame (ORF) for more than 40 million years. It was therefore possible that primate EBLNs have encoded functional proteins during evolution. To examine this possibility, natural selection operating on all ORFs of primate EBLN-1 to -4 was examined by comparing the rates of synonymous and nonsynonymous substitutions. The expected number of premature termination codons in EBLN-1 generated after the divergence of Old World and New World monkeys under the selective neutrality was also examined by the Monte Carlo simulation. As a result, natural selection was not identified for the entire region as well as parts of ORFs in the pairwise analysis of primate EBLN-1 to -4 and for any branch of the phylogenetic trees for EBLN-1 to -4 after the divergence of Old World and New World monkeys. Computer simulation also indicated that the absence of premature termination codon in the present-day EBLN-1 does not necessarily support the maintenance of function after the divergence of Old World and New World monkeys. These results suggest that EBLNs have not generally encoded functional proteins after the divergence of Old World and New World monkeys.

Activity budget and behavioural patterns of free-ranging yellow-tailed woolly monkeys Oreonax flavicauda (Mammalia: Primates), at La Esperanza, northeastern Peru

Abstract: The critically endangered yellow-tailed woolly monkey (Oreonax flavicauda ) is endemic to the cloud forests of north-eastern Peru and one of the least studied of all primate species. We conducted fifteen months of group follows using focal animal sampling techniques to gather the first behavioural data on free ranging O. flavicauda. Group follows took place in an area of disturbed primary and regenerating secondary forest near the village of La Esperanza, Amazonas department. Yellow-tailed woolly monkey activity budgets at La Esperanza average: 29.8% feeding, 26.3% resting, 29.0% travelling, 2.3% in social and 12.8% in other activities. Significant differences were observed in the frequency of behaviours between age/sex classes as well as on temporal scales. Our findings are similar to those of other woolly monkey species although yellow-tailed woolly monkeys were found to be more vocally active then other species. We recommend further study of this species at other sites with different forest types to better understand its behavioural ecology and conservation needs. Particular emphasis should be given to studying this species at different altitudes.

RESEARCH ARTICLE Patterns of Mineral Lick Visitation by Spider Monkeys and Howler Monkeys in Amazonia: Are Licks Perceived as Risky Areas?

Abstract: Mineral licks—also known as ‘‘salados,’’ ‘‘saladeros,’’ or ‘‘collpas’’—are specific sites in tropical and temperate ecosystems where a large diversity of mammals and birds come regularly to feed on soil. Although the reasons for vertebrate geophagy are not completely understood, animals are argued to obtain a variety of nutritional and health benefits from the ingestion of soil at mineral licks. We studied the temporal patterns of mineral lick use by white-bellied spider monkey (Ateles belzebuth) and red howler monkey (Alouatta seniculus) in a lowland rain forest in Amazonian Ecuador. Using camera and video traps at four different mineral licks, combined with behavioral follows of one group of spider monkeys, we documented rates of mineral lick visitation by both primate species and the relative frequency and intensity of mineral lick use by spider monkeys. On the basis of 1,612 days and 888 nights of mineral lick monitoring, we found that A. belzebuth and A. seniculus both visit mineral licks frequently throughout the year (on average 14% of days for both species), and mineral lick visitation was influenced by short-term environmental conditions (e.g. sunny and dry weather). For spider monkeys, the area surrounding the lick was also the most frequently and most intensively used region within the group’s home range. The fact that spider monkeys spent long periods at the lick area before coming to the ground to obtain soil, and the fact that both species visited the lick preferentially during dry sunny conditions (when predator detectability is presumed to be relatively high) and visited simultaneously more often than expected by chance, together suggest that licks are indeed perceived as risky areas by these primates. We suggest that howler and spider monkeys employ behavioral strategies aimed at minimizing the probability of predation while visiting the forest floor at risky mineral lick sites. Am. J. Primatol. 73:386–396, 2011. r 2010 Wiley-Liss, Inc.

Proboscis monkeys (nasalis larvatus (wurmb, 1787)) have unusually high-pitched vocalizations

Abstract: According to qualitative descriptions, proboscis monkeys have high frequency vocalizations, but no technical analysis of the calls is available because the species is rare, diffi cult to study in the fi eld, and few zoological institutions have breeding populations. Here we analyse the high pitch vocalizations of captive proboscis monkeys in the Singapore Zoological Gardens. The monkeys produce very high frequency tonal vocalizations ranging from 1.4 kHz to 6.8 kHz. The calls are produced during acts of aggression or used as alarm calls and the pitch is higher than expected based on a comparative study for such a large primate. We discuss that the high frequency may be an adaptation for predator avoidance (crocodiles) and/or communication in dense vegetation.

Physical intuitions about support relations in monkeys (Macaca fuscata) and apes (Pan troglodytes).

Abstract: Nonhuman primates, like humans, have demonstrated various physical intuitions. Cacchione and Krist (2004) examined chimpanzees’ intuitions about support relations with the violation-of-expectation task. They reported that the chimpanzees possessed intuitions about support, but their intuitions differed from those of humans in part; they were sensitive to “contact/no-contact” and “amount of contact” but not “type of contact” rule. To further explore intuitions about support in nonhuman primates, we conducted similar experiments on monkeys (Japanese monkeys) and apes (chimpanzees). In three experiments, we presented physically possible and impossible events of different support relations to the participants and measured their looking times. The results reveal that the chimpanzees and monkeys detect the violations of “contact/no-contact” and “amount of contact” but not “type of contact” variable. Therefore, the apes and monkeys possess similar intuitions; however, these intuitions differ in part from those of humans. The present study provides new and corroborative evidence of intuitions about support in nonhuman primates. However, this again leads to the question of distinctive understanding about support relations among primate species.