Tetsuro Matsuzawa

Japan Monkey Centre, Inuyama-chō, Gifu, Japan

Are you Tetsuro Matsuzawa?

Claim your profile

Publications (169)649.48 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We are in a new epoch, the Anthropocene, and research into our closest living relatives, the great apes, must keep pace with the rate that our species is driving change. While a goal of many studies is to understand how great apes behave in natural contexts, the impact of human activities must increasingly be taken into account. This is both a challenge and an opportunity, which can importantly inform research in three diverse fields: cognition, human evolution, and conservation. No long-term great ape research site is wholly unaffected by human influence , but research at those that are especially affected by human activity is particularly important for ensuring that our great ape kin survive the Anthropocene. Understanding the human–ape interface A primary goal of many field studies of animal behaviour is to obtain data on behaviour in the ecological contexts in which that behaviour is presumed to have evolved. Hence, for many research questions, scientists rightly seek to study populations in places remote from dense human settlements and minimally disturbed by human activities. While many researchers have thereby focused little attention on human impacts, the scale of impacts at many sites is now substantial enough that they should be explicitly taken into account. Given that great apes (here also referred to as apes) reproduce slowly and require natural forest for food and shelter, impacts such as hunting and
    Trends in Ecology & Evolution 04/2015; · 15.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We are in a new epoch, the Anthropocene, and research into our closest living relatives, the great apes, must keep pace with the rate that our species is driving change. While a goal of many studies is to understand how great apes behave in natural contexts, the impact of human activities must increasingly be taken into account. This is both a challenge and an opportunity, which can importantly inform research in three diverse fields: cognition, human evolution, and conservation. No long-term great ape research site is wholly unaffected by human influence, but research at those that are especially affected by human activity is particularly important for ensuring that our great ape kin survive the Anthropocene. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Trends in Ecology & Evolution 04/2015; DOI:10.1016/j.tree.2015.02.002 · 15.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We are in a new epoch, the Anthropocene, and research into our closest living relatives, the great apes, must keep pace with the rate that our species is driving change. While a goal of many studies is to understand how great apes behave in natural contexts, the impact of human activities must increasingly be taken into account. This is both a challenge and an opportunity, which can importantly inform research in three diverse fields: cognition, human evolution, and conservation. No long-term great ape research site is wholly unaffected by human influence , but research at those that are especially affected by human activity is particularly important for ensuring that our great ape kin survive the Anthropocene. Understanding the human–ape interface A primary goal of many field studies of animal behaviour is to obtain data on behaviour in the ecological contexts in which that behaviour is presumed to have evolved. Hence, for many research questions, scientists rightly seek to study populations in places remote from dense human settlements and minimally disturbed by human activities. While many researchers have thereby focused little attention on human impacts, the scale of impacts at many sites is now substantial enough that they should be explicitly taken into account. Given that great apes (here also referred to as apes) reproduce slowly and require natural forest for food and shelter, impacts such as hunting and
    Trends in Ecology & Evolution 04/2015; · 15.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We are in a new epoch, the Anthropocene, and research into our closest living relatives, the great apes, must keep pace with the rate that our species is driving change. While a goal of many studies is to understand how great apes behave in natural contexts, the impact of human activities must increasingly be taken into account. This is both a challenge and an opportunity, which can importantly inform research in three diverse fields: cognition, human evolution, and conservation. No long-term great ape research site is wholly unaffected by human influence , but research at those that are especially affected by human activity is particularly important for ensuring that our great ape kin survive the Anthropocene. Understanding the human–ape interface A primary goal of many field studies of animal behaviour is to obtain data on behaviour in the ecological contexts in which that behaviour is presumed to have evolved. Hence, for many research questions, scientists rightly seek to study populations in places remote from dense human settlements and minimally disturbed by human activities. While many researchers have thereby focused little attention on human impacts, the scale of impacts at many sites is now substantial enough that they should be explicitly taken into account. Given that great apes (here also referred to as apes) reproduce slowly and require natural forest for food and shelter, impacts such as hunting and
    Trends in Ecology & Evolution 04/2015; · 15.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Stone tool use by wild chimpanzees of West Africa offers a unique opportunity to explore the evolutionary roots of technology during human evolution. However, detailed analyses of chimpanzee stone artifacts are still lacking, thus precluding a comparison with the earliest archaeological record. This paper presents the first systematic study of stone tools used by wild chimpanzees to crack open nuts in Bossou (Guinea-Conakry), and applies pioneering analytical techniques to such artifacts. Automatic morphometric GIS classification enabled to create maps of use wear over the stone tools (anvils, hammers, and hammers/ anvils), which were blind tested with GIS spatial analysis of damage patterns identified visually. Our analysis shows that chimpanzee stone tool use wear can be systematized and specific damage patterns discerned, allowing to discriminate between active and passive pounders in lithic assemblages. In summary, our results demonstrate the heuristic potential of combined suites of GIS techniques for the analysis of battered artifacts, and have enabled creating a referential framework of analysis in which wild chimpanzee battered tools can for the first time be directly compared to the early archaeological record.
    PLoS ONE 03/2015; DOI:10.1371/journal.pone.0121613 · 3.53 Impact Factor
  • Source
    American Journal of Primatology 01/2015; 77:319-329. · 2.14 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We discovered a lethal hemorrhagic syndrome arising from severe thrombocytopenia in Japanese macaques kept at the Primate Research Institute, Kyoto University. Extensive investigation identified that simian retrovirus type 4 (SRV-4) was the causative agent of the disease. SRV-4 had previously been isolated only from cynomolgus macaques in which it is usually asymptomatic. We consider that the SRV-4 crossed the so-called species barrier between cynomolgus and Japanese macaques, leading to extremely severe acute symptoms in the latter. Infectious agents that cross the species barrier occasionally amplify in virulence, which is not observed in the original hosts. In such cases, the new hosts are usually distantly related to the original hosts. However, Japanese macaques are closely related to cynomolgus macaques, and can even hybridize when given the opportunity. This lethal outbreak of a novel pathogen in Japanese macaques highlights the need to modify our expectations about virulence with regards crossing species barriers.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Induced pluripotent stem cells (iPSCs) are potentially valuable cell sources for disease models and future therapeutic applications; however, inefficient generation and the presence of integrated transgenes remain as problems limiting their current use. Here, we developed a new Sendai virus vector, TS12KOS, which has improved efficiency, does not integrate into the cellular DNA, and can be easily eliminated. TS12KOS carries KLF4, OCT3/4, and SOX2 in a single vector and can easily generate iPSCs from human blood cells. Using TS12KOS, we established iPSC lines from chimpanzee blood, and used DNA array analysis to show that the global gene-expression pattern of chimpanzee iPSCs is similar to those of human embryonic stem cell and iPSC lines. These results demonstrated that our new vector is useful for generating iPSCs from the blood cells of both human and chimpanzee. In addition, the chimpanzee iPSCs are expected to facilitate unique studies into human physiology and disease.
    PLoS ONE 12/2014; 9(12):e113052. DOI:10.1371/journal.pone.0113052 · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To examine the evolutional origin of representational drawing, two experiments directly compared the drawing behavior of human children and chimpanzees. The first experiment observed free drawing after model presentation, using imitation task. From longitudinal observation of humans (N = 32, 11–31 months), the developmental process of drawing until the emergence of shape imitation was clarified. Adult chimpanzees showed the ability to trace a model, which was difficult for humans who had just started imitation. The second experiment, free drawing on incomplete facial stimuli, revealed the remarkable difference between two species. Humans (N = 57, 6–38 months) tend to complete the missing parts even with immature motor control, whereas chimpanzees never completed the missing parts and instead marked the existing parts or traced the outlines. Cognitive characteristics may affect the emergence of representational drawings.
    Child Development 11/2014; 85(6). DOI:10.1111/cdev.12319 · 4.92 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Chimpanzees are renowned for their use of foraging tools in harvesting social insects and some populations use tools to prey on aggressive army ants (Dorylus spp.). Tool use in army ant predation varies across chimpanzee study sites with differences in tool length, harvesting technique, and army ant species targeted. However, surprisingly little is known about the detailed ecology of army ant predation. We studied army ant predation by chimpanzees (Pan troglodytes verus) at the Seringbara study site in the Nimba Mountains, Guinea (West Africa), over 10 years (2003–2013). We investigated chimpanzee selectivity with regards to army ant prey species. We assessed the temporal variation in army ant-feeding and examined whether army ant predation was related to rainfall or ripe fruit availability. Moreover, we examined whether chimpanzees showed selectivity regarding plant species used for tool manufacture, as well as the relationship between tool species preference and tool collection distance. Lastly, we measured tool properties and investigated the use of tool sets and composite tools in army ant predation. Seringbara chimpanzees preyed on one army ant species (D. nigricans) more often than expected based on encounter rates, which may be explained by the overlap in altitudinal distribution between chimpanzees and D. nigricans. Army ant predation was not related to rainfall or fruit availability. Chimpanzees were selective in their choice of tool materials and collected their preferred tool species (Alchornea hirtella) from greater distances than they did other species. Lastly, Seringbara chimpanzees used both tool sets and composite tools (tree perch) in army ant predation. Tool types (dig vs. dip) differed in width and strength, but not length. Tool composites were found at 40% of ant-feeding sites. Our study sheds new light on the ecology of army ant predation and provides novel insights into chimpanzee selection of army ant prey and tool species. Am. J. Primatol. © 2014 Wiley Periodicals, Inc.
    American Journal of Primatology 10/2014; 77(3). DOI:10.1002/ajp.22347 · 2.14 Impact Factor
  • Mariska E Kret, Masaki Tomonaga, Tetsuro Matsuzawa
    [Show abstract] [Hide abstract]
    ABSTRACT: Group-living typically provides benefits to individual group members but also confers costs. To avoid incredulity and betrayal and allow trust and cooperation, individuals must understand the intentions and emotions of their group members. Humans attend to other's eyes and from gaze and pupil-size cues, infer information about the state of mind of the observed. In humans, pupil-size tends to mimic that of the observed. Here we tested whether pupil-mimicry exists in our closest relative, the chimpanzee (P. troglodytes). We conjectured that if pupil-mimicry has adaptive value, e.g. to promote swift communication of inner states and facilitate shared understanding and coordination, pupil-mimicry should emerge within but not across species. Pupillometry data was collected from human and chimpanzee subjects while they observed images of the eyes of both species with dilating/constricting pupils. Both species showed enhanced pupil-mimicry with members of their own species, with effects being strongest in humans and chimpanzee mothers. Pupil-mimicry may be deeply-rooted, but probably gained importance from the point in human evolution where the morphology of our eyes became more prominent. Humans' white sclera surrounding the iris, and the fine muscles around their eyes facilitate non-verbal communication via eye signals.
    PLoS ONE 08/2014; 9(8):e104886. DOI:10.1371/journal.pone.0104886 · 3.53 Impact Factor
    This article is viewable in ResearchGate's enriched format
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Knowledge of the context and development of playful expressions in chimpanzees is limited because research has tended to focus on social play, on older subjects, and on the communicative signaling function of expressions. Here we explore the rate of playful facial and body expressions in solitary and social play, changes from 12-to 15-months of age, and the extent to which social partners match expressions, which may illuminate a route through which context influences expression. Naturalistic observations of seven chimpanzee infants (Pan troglodytes) were conducted at Chester Zoo, UK (n = 4), and Primate Research Institute, Japan (n = 3), and at two ages, 12 months and 15 months. No group or age differences were found in the rate of infant playful expressions. However, modalities of playful expression varied with type of play: in social play, the rate of play faces was high, whereas in solitary play, the rate of body expressions was high. Among the most frequent types of play, mild contact social play had the highest rates of play faces and multi-modal expressions (often play faces with hitting). Social partners matched both infant play faces and infant body expressions, but play faces were matched at a significantly higher rate that increased with age. Matched expression rates were highest when playing with peers despite infant expressiveness being highest when playing with older chimpanzees. Given that playful expressions emerge early in life and continue to occur in solitary contexts through the second year of life, we suggest that the play face and certain body behaviors are emotional expressions of joy, and that such expressions develop additional social functions through interactions with peers and older social partners.
    Frontiers in Psychology 07/2014; 5. DOI:10.3389/fpsyg.2014.00741 · 2.80 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The capacity for strategic thinking about the payoff-relevant actions of conspecifics is not well understood across species. We use game theory to make predictions about choices and temporal dynamics in three abstract competitive situations with chimpanzee participants. Frequencies of chimpanzee choices are extremely close to equilibrium (accurate-guessing) predictions, and shift as payoffs change, just as equilibrium theory predicts. The chimpanzee choices are also closer to the equilibrium prediction, and more responsive to past history and payoff changes, than two samples of human choices from experiments in which humans were also initially uninformed about opponent payoffs and could not communicate verbally. The results are consistent with a tentative interpretation of game theory as explaining evolved behavior, with the additional hypothesis that chimpanzees may retain or practice a specialized capacity to adjust strategy choice during competition to perform at least as well as, or better than, humans have.
    Scientific Reports 06/2014; 4:5182. DOI:10.1038/srep05182 · 5.08 Impact Factor
  • Source
    Primate Research 01/2014; 30(1):147-156. DOI:10.2354/psj.30.009
  • Source
    Christopher Flynn Martin, Dora Biro, Tetsuro Matsuzawa
    [Show abstract] [Hide abstract]
    ABSTRACT: We report on the development of a novel shared touch-panel apparatus for examining a diverse range of topics in great ape social cognition and interaction. Our apparatus-named the Arena System-is composed of a single multitouch monitor that spans across two separate testing booths, so that individuals situated in each booth have tactile access to half of the monitor and visual access to the whole monitor. Additional components of the system include a smart-film barrier able to restrict visual access between the booths, as well as two automated feeding devices that dispense food rewards to the subjects. The touch-panel, smart-film, and feeders are controlled by a PC that is also responsible for running the experimental tasks. We present data from a pilot behavioral game theory study with two chimpanzees in order to illustrate the efficacy of our method, and we suggest applications for a range of topics including animal social learning, coordination, and behavioral economics. The system enables fully automated experimental procedures, which means that no human participation is needed to run the tasks. The novel use of a touch-panel in a social setting allows for a finer degree of data resolution than do the traditional experimental apparatuses used in prior studies on great ape social interaction.
    Behavior Research Methods 12/2013; 46(3). DOI:10.3758/s13428-013-0418-y · 2.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An intracranial arachnoid cyst was detected in a 32-year-old, 44.6-kg, female chimpanzee at the Primate Research Institute, Kyoto University. Magnetic resonance imaging (MRI) and computed tomography (CT) were performed and the cognitive studies in which she participated were reviewed. MRI revealed that the cyst was present in the chimpanzee's right occipital convexity, and was located in close proximity to the posterior horn of the right lateral ventricle without ventriculomegaly. CT confirmed the presence of the cyst and no apparent signs indicating previous skull fractures were found. The thickness of the mandible was asymmetrical, whereas the temporomandibular joints and dentition were symmetrical. She showed no abnormalities in various cognitive studies since she was 3 years old, except a different behavioural pattern during a recent study, indicating a possible visual field defect. Detailed cognitive studies, long-term observation of her physical condition and follow-up MRI will be continued.
    Primates 09/2013; 55(1). DOI:10.1007/s10329-013-0384-0 · 1.40 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An adult male chimpanzee living in a captive social group at the Primate Research Institute of Kyoto University developed acute tetraparesis. He was paralyzed and received intensive care and veterinary treatment as previously reported in Miyabe-Nishiwaki et al. (J Med Primatol 39:336-346, 2010). The behavioral recovery of the chimpanzee was longitudinally monitored using an index of upright posture between 0 and 41 months after the onset of tetraparesis. Four phases were identified during the course of behavioral recovery. During Phase 0 (0-13 months), the chimpanzee remained lying on his back during the absence of human caretakers. An increase in upright posture occurred in Phase I (14-17 months), then remained at a stable level of around 50-70 % in Phase II (18-29 months). During Phases I and II, the subject's small treatment cage represented a spatial limitation. Thus, behavioral recovery was mainly mediated by arm muscle strengthening caused by raising the body trunk with the aid of materials attached to the cage walls as environmental enrichment. When the chimpanzee was moved to a larger rehabilitation room in Phase III (30-41 months), the percentage of upright posture constantly exceeded 80 %, except in the 40th month when he injured his ankle and was inactive for several days. The enlargement of the living space had a positive effect on behavioral recovery by increasing the types of locomotion exhibited by the subject, including the use of legs during walking. Rehabilitation works were applied in face-to-face situations which enabled the use of rehabilitation methods used in humans. The process of behavioral recovery reported in this study provides a basic data set for planning future rehabilitation programs and for comparisons with further cases of physical disability in non-human primates.
    Primates 05/2013; DOI:10.1007/s10329-013-0358-2 · 1.40 Impact Factor
  • Source
  • Yuko Hattori, Masaki Tomonaga, Tetsuro Matsuzawa
    [Show abstract] [Hide abstract]
    ABSTRACT: Humans actively use behavioral synchrony such as dancing and singing when they intend to make affiliative relationships. Such advanced synchronous movement occurs even unconsciously when we hear rhythmically complex music. A foundation for this tendency may be an evolutionary adaptation for group living but evolutionary origins of human synchronous activity is unclear. Here we show the first evidence that a member of our closest living relatives, a chimpanzee, spontaneously synchronizes her movement with an auditory rhythm: After a training to tap illuminated keys on an electric keyboard, one chimpanzee spontaneously aligned her tapping with the sound when she heard an isochronous distractor sound. This result indicates that sensitivity to, and tendency toward synchronous movement with an auditory rhythm exist in chimpanzees, although humans may have expanded it to unique forms of auditory and visual communication during the course of human evolution.
    Scientific Reports 03/2013; 3:1566. DOI:10.1038/srep01566 · 5.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Developmental prolongation is thought to contribute to the remarkable brain enlargement observed in modern humans (Homo sapiens). However, the developmental trajectories of cerebral tissues have not been explored in chimpanzees (Pan troglodytes), even though they are our closest living relatives. To address this lack of information, the development of cerebral tissues was tracked in growing chimpanzees during infancy and the juvenile stage, using three-dimensional magnetic resonance imaging and compared with that of humans and rhesus macaques (Macaca mulatta). Overall, cerebral development in chimpanzees demonstrated less maturity and a more protracted course during prepuberty, as observed in humans but not in macaques. However, the rapid increase in cerebral total volume and proportional dynamic change in the cerebral tissue in humans during early infancy, when white matter volume increases dramatically, did not occur in chimpanzees. A dynamic reorganization of cerebral tissues of the brain during early infancy, driven mainly by enhancement of neuronal connectivity, is likely to have emerged in the human lineage after the split between humans and chimpanzees and to have promoted the increase in brain volume in humans. Our findings may lead to powerful insights into the ontogenetic mechanism underlying human brain enlargement.
    Proceedings of the Royal Society B: Biological Sciences 02/2013; 280(1753):20122398. DOI:10.1098/rspb.2012.2398 · 5.29 Impact Factor

Publication Stats

3k Citations
649.48 Total Impact Points

Institutions

  • 2015
    • Japan Monkey Centre
      Inuyama-chō, Gifu, Japan
  • 1981–2015
    • Kyoto University
      • Primate Research Institute
      Kioto, Kyōto, Japan
  • 2012
    • University of Cambridge
      • Leverhulme Centre for Human Evolutionary Studies
      Cambridge, England, United Kingdom
  • 2011
    • Charité Universitätsmedizin Berlin
      • Department of Psychiatry and Psychotherapy
      Berlin, Land Berlin, Germany
  • 2010
    • Kyoto Prefectural University
      • Graduate School of Life and Environmental Sciences
      Kyoto, Kyoto-fu, Japan
    • University of Oxford
      • Department of Zoology
      Oxford, ENG, United Kingdom
  • 2009–2010
    • New University of Lisbon
      • Department of Anthropology
      Caparica, Distrito de Setubal, Portugal
    • National Research Council
      • Institute of Cognitive Sciences and Technologies ISTC
      Roma, Latium, Italy
    • Centro em Rede de Investigação em Antropologia
      Lisboa, Lisbon, Portugal
  • 2008
    • University of Coimbra
      • Faculdade de Ciências e Tecnologia
      Coimbra, Distrito de Coimbra, Portugal
  • 2002–2008
    • Nagoya University
      • Graduate School of Environmental Studies
      Nagoya-shi, Aichi-ken, Japan
  • 2007
    • Universiteit Utrecht
      • Division of Behavioural Biology
      Utrecht, Provincie Utrecht, Netherlands
  • 2001–2005
    • University of Stirling
      • Department of Psychology
      Stirling, SCT, United Kingdom
  • 2004
    • The University of Shiga Prefecture
      • School of Human Cultures
      Hikone, Shiga, Japan
  • 2003
    • Rutgers, The State University of New Jersey
      • Department of Anthropology
      New Brunswick, NJ, United States
  • 1997
    • Kwansei Gakuin University
      Nishinomiya, Hyōgo, Japan
  • 1992
    • Osaka University of Human Sciences
      Ōsaka, Ōsaka, Japan