Tetsuro Matsuzawa

Japan Monkey Centre, Inuyama-chō, Gifu, Japan

Are you Tetsuro Matsuzawa?

Claim your profile

Publications (202)707.29 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Despite intensive observation of nonhuman great apes during long-term field studies, observations of great ape births in the wild are rare. Research on wild chimpanzees (Pan troglodytes verus) at Bossou in the Republic of Guinea has been ongoing for 35 years, yet chimpanzee parturitions have been observed on only two occasions. Here we provide information regarding both chimpanzee births, with detailed information from the close observation of one. During this birth, the mother built a day nest in a tree before parturition. After giving birth, the mother consumed the placenta, and the other chimpanzees in her party gathered near her and her neonate. However, she did not share the placenta, and consumed it all herself. In the second observation, the mother also built a nest in a tree and subsequently gave birth. Thereafter, she shared the placenta with some individuals and consumed part of the placenta herself. Although maternal placentophagy is a ubiquitous behavior among the majority of non-human primates, observations of placenta sharing by wild primates are infrequent, and the proximate and ultimate explanations for the behavior remain unclear.
    No preview · Article · Jan 2016 · Primates
  • Source

    Preview · Article · Nov 2015 · Biology letters
  • Source
    Marine Levé · Cédric Sueur · Odile Petit · Tetsuro Matsuzawa · Satoshi Hirata
    [Show abstract] [Hide abstract]
    ABSTRACT: Many chimpanzees throughout the world are housed in captivity, and there is an increasing effort to recreate social groups by mixing individuals with captive origins with those with wild origins. Captive origins may entail restricted rearing conditions during early infant life, including, for example, no maternal rearing and a limited social life. Early rearing conditions have been linked with differences in tool-use behavior between captive- and wild-born chimpanzees. If physical cognition can be impaired by non-natural rearing, what might be the consequences for social capacities? This study describes the results of network analysis based on grooming interactions in chimpanzees with wild and captive origins living in the Kumamoto Sanctuary in Kumamoto, Japan. Grooming is a complex social activity occupying up to 25 % of chimpanzees' waking hours and plays a role in the emergence and maintenance of social relationships. We assessed whether the social centralities and roles of chimpanzees might be affected by their origin (captive vs wild). We found that captive- and wild-origin chimpanzees did not differ in their grooming behavior, but that theoretical removal of individuals from the network had differing impacts depending on the origin of the individual. Contrary to findings that non-natural early rearing has long-term effects on physical cognition, living in social groups seems to compensate for the negative effects of non-natural early rearing. Social network analysis (SNA) and, in particular, theoretical removal analysis, were able to highlight differences between individuals that would have been impossible to show using classical methods. The social environment of captive animals is important to their well-being, and we are only beginning to understand how SNA might help to enhance animal welfare.
    Full-text · Article · Sep 2015 · Primates
  • Source
    Yuko Hattori · Masaki Tomonaga · Tetsuro Matsuzawa
    [Show abstract] [Hide abstract]
    ABSTRACT: Humans tend to spontaneously align their movements in response to visual (e.g., swinging pendulum) and auditory rhythms (e.g., hearing music while walking). Particularly in the case of the response to auditory rhythms, neuroscientific research has indicated that motor resources are also recruited while perceiving an auditory rhythm (or regular pulse), suggesting a tight link between the auditory and motor systems in the human brain. However, the evolutionary origin of spontaneous responses to auditory rhythms is unclear. Here, we report that chimpanzees and humans show a similar distractor effect in perceiving isochronous rhythms during rhythmic movement. We used isochronous auditory rhythms as distractor stimuli during self-paced alternate tapping of two keys of an electronic keyboard by humans and chimpanzees. When the tempo was similar to their spontaneous motor tempo, tapping onset was influenced by intermittent entrainment to auditory rhythms. Although this effect itself is not an advanced rhythmic ability such as dancing or singing, our results suggest that, to some extent, the biological foundation for spontaneous responses to auditory rhythms was already deeply rooted in the common ancestor of chimpanzees and humans, 6 million years ago. This also suggests the possibility of a common attentional mechanism, as proposed by the dynamic attending theory, underlying the effect of perceiving external rhythms on motor movement.
    Full-text · Article · Jul 2015 · PLoS ONE
  • Source

    Full-text · Dataset · Jun 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: African apes and humans share a genetic mutation that enables them to effectively metabolize ethanol. However, voluntary ethanol consumption in this evolutionary radiation is documented only in modern humans. Here, we report evidence of the long-term and recurrent ingestion of ethanol from the raffia palm (Raphia hookeri, Arecaceae) by wild chimpanzees (Pan troglodytes verus) at Bossou in Guinea, West Africa, from 1995 to 2012. Chimpanzees at Bossou ingest this alcoholic beverage, often in large quantities, despite an average presence of ethanol of 3.1% alcohol by volume (ABV) and up to 6.9% ABV. Local people tap raffia palms and the sap collects in
    Full-text · Article · Jun 2015 · Royal Society Open Science
  • 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.
    Full-text · Article · Apr 2015 · Trends in Ecology & Evolution
  • 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
    Full-text · Article · Apr 2015 · Trends in Ecology & Evolution
  • 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
    Full-text · Article · Apr 2015 · Trends in Ecology & Evolution
  • 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
    Full-text · Article · Apr 2015 · Trends in Ecology & Evolution
  • 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.
    Full-text · Article · Mar 2015 · PLoS ONE
  • 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.
    Full-text · Article · Mar 2015 · Scientific Reports
  • Source

    Full-text · Article · Jan 2015 · American Journal of Primatology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Great Ape Information Network has collated and archived information on captive chimpanzees within Japan since 2002. As of July 1st, 2014, a total of 323 chimpanzees were housed within 52 facilities across Japan, all registered in the Japanese Association of Zoos and Aquariums (JAZA) studbook. JAZA has recorded information on captive chimpanzees within Japan since the 1980s. However, for individuals unregistered and/or deceased prior to this period, JAZA holds scant information. There are very few surviving reports on living conditions and husbandry of such individuals, particularly for the years preceding the Second World War (WWII) (up to 1945). Here we present the first detailed history of captive chimpanzees in Japan before WWII, following a systematic investigation of disparate records. The first record of any live chimpanzee within Japan was a chimpanzee accompanying an Italian travelling circus in 1921. The history of resident captive chimpanzees in Japan began in 1927 when a chimpanzee, imported into Japan by a visitor, was exhibited in Osaka zoo. In the 1930s, many chimpanzee infants were imported to Japanese zoos until in 1941 imports were halted because of WWII. By the end of WWII, there was only one single chimpanzee still alive within Japan, “Bamboo”, housed in Nagoya. In 1951, importation of wild chimpanzees into Japan resumed. In total, we identified 28 individuals housed within Japan before 1945, none listed previously in the JAZA studbook. Of these 28 individuals: 6 entered Japan as pets and/or circus animals, 21 were imported to zoos, and one was stillborn in zoo. Of the 21 zoo-housed individuals, 7 died within one year and 9 of the remaining 14 were dead within 5 years of arriving in Japan. Four individuals are recorded to have lived 7-8 years. Only one male individual, the aforementioned “Bamboo”, lived notably longer, to about 14 years.
    Full-text · Article · Jan 2015 · Primate Research
  • Nicola Bryson-Morrison · Tatyana Humle · Tetsuro Matsuzawa

    No preview · Article · Jan 2015 · Folia Primatologica
  • 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.
    Full-text · Article · Dec 2014 · PLoS ONE

  • No preview · Conference Paper · Nov 2014
  • Aya Saito · Misato Hayashi · Hideko Takeshita · Tetsuro Matsuzawa
    [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.
    No preview · Article · Nov 2014 · Child Development
  • [Show abstract] [Hide abstract]
    ABSTRACT: We investigated nesting behavior of non habituated chimpanzees populating the Nimba Mountains to document their abundance and their criterions of nesting-site selection. During a 19-month study we walked 80 km of transects and recces each month, and recorded 764 nests (mean group size = 2.23 nests) along with characteristics of vegetation structure and composition, topography, and seasonality. Population density estimated with two nest count methods ranged between 0.14 and 0.65 chimpanzee/km2. These values are lower than previous estimates, emphasizing the necessity of protecting remaining wild ape populations. Chimpanzees built nests in 108 tree species out of 437 identified, but 2.3% of total species comprised 52% of nests. Despite they preferred nesting in trees of 25–29 cm DBH and at a mean height of 8.02 m, we recorded an important proportion of terrestrial nests (8.2%) that may reflect a cultural trait of Nimba chimpanzees. A logistic model of nest presence formulated as a function of 12 habitat variables revealed preference for gallery and mountain forests rather than lowland forest, and old-growth forest rather than secondary forests. They nested more frequently in the study area during the dry season (December–April). The highest probability of observing nests was at 770 m altitude, particularly in steep locations (mean ground declivity = 15.54%). Several of the reported nest characteristics combined with the existence of two geographically separated clusters of nest, suggest that the study area constitutes the non-overlapping peripheral areas of two distinct communities. This nest-based study led us to findings on the behavioral ecology of Nimba chimpanzees, which constitute crucial knowledge to implement efficient and purpose-built conservation. Am. J. Primatol. © 2014 Wiley Periodicals, Inc.
    No preview · Article · Nov 2014 · American Journal of Primatology
  • 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.
    Full-text · Article · Oct 2014 · American Journal of Primatology

Publication Stats

5k Citations
707.29 Total Impact Points

Institutions

  • 2015
    • Japan Monkey Centre
      Inuyama-chō, Gifu, Japan
  • 1981-2015
    • Kyoto University
      • Primate Research Institute
      Kioto, Kyōto, Japan
  • 2005
    • University of Portsmouth
      • Department of Psychology
      Portsmouth, England, United Kingdom