Published Papers - Matsumoto Akiko

How to treat mixed behavior segments in supervised machine learning of behavioral modes from inertial measurement data

Resheff Y, Bensch H M, Zottl M, Harel R, Matsumoto-Oda A, Crofoot M, Gomez S, Börger L, Rotics S

Moving Ecology   12 ( 44 )   2024.06 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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The application of supervised machine learning methods to identify behavioural modes from inertial measurements of bio-loggers has become a standard tool in behavioural ecology. Several design choices can affect the accuracy of identifying the behavioural modes. One such choice is the inclusion or exclusion of segments consisting of more than a single behaviour (mixed segments) in the machine learning model training data. Currently, the common practice is to ignore such segments during model training. In this paper we tested the hypothesis that including mixed segments in model training will improve accuracy, as the model would perform better in identifying them in the test data. We test this hypothesis using a series of data simulations on four datasets of accelerometer data coupled with behaviour observations, obtained from four study species (Damaraland mole-rats, meerkats, olive baboons, polar bears). Results show that when a substantial proportion of the test data are mixed behaviour segments (above ~ 10%), including mixed segments in machine learning model training improves the accuracy of classification. These results were consistent across the four study species, and robust to changes in segment length, sample size, and degree of mixture within the mixed segments. However, we also find that in some cases (particularly in baboons) models trained with mixed segments show reduced accuracy in classifying test data containing only single behaviour (pure) segments, compared to models trained without mixed segments. Based on these results, we recommend that when the classification model is expected to deal with a substantial proportion of mixed behaviour segments (> 10%), it is beneficial to include them in model training, otherwise, it is unnecessary but also not harmful. The exception is when there is a basis to assume that the training data contains a higher rate of mixed segments than the actual (unobserved) data to be classified—such a situation may occur particularly when training data are collected in captivity and used to classify data from the wild. In this case, excess inclusion of mixed segments in training data should probably be avoided.

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Reduction of bitter taste receptor gene family in folivorous Colobines as compared with omnivorous Cercopithecines in Primates

Hou M, Akhtar MS, Hayashi M, Ashino, Matsumoto-Oda A, Hayakawa T, Ishida T, Melin AD, Imai H, Kawamura S

Primates   65   311 - 331   2024 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Bitter taste perception is important in preventing animals from ingesting potentially toxic compounds. Whole-genome assembly (WGA) data have revealed that bitter taste receptor genes (TAS2Rs) comprise a multigene family with dozens of intact and disrupted genes in primates. However, publicly available WGA data are often incomplete, especially for multigene families. In this study, we employed a targeted capture (TC) approach specifically probing TAS2Rs for ten species of cercopithecid primates with diverse diets, including eight omnivorous cercopithecine species and two folivorous colobine species. We designed RNA probes for all TAS2Rs that we modeled to be intact in the common ancestor of cercopithecids (“ancestral-cercopithecid TAS2R gene set”). The TC was followed by short-read and high-depth massive-parallel sequencing. TC retrieved more intact TAS2R genes than found in WGA databases. We confirmed a large number of gene “births” at the common ancestor of cercopithecids and found that the colobine common ancestor and the cercopithecine common ancestor had contrasting trajectories: four gene “deaths” and three gene births, respectively. The number of intact TAS2R genes was markedly reduced in colobines (25–28 detected via TC and 20–26 detected via WGA analysis) as compared with cercopithecines (27–36 via TC and 19–30 via WGA). Birth or death events occurred at almost every phylogenetic-tree branch, making the composition of intact genes variable among species. These results show that evolutionary change in intact TAS2R genes is a complex process, refute a simple general prediction that herbivory favors more TAS2R genes, and have implications for understanding dietary adaptations and the evolution of detoxification abilities.

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Estimating individual exposure to predation risk in group-living baboons, Papio anubis.

Suire A, Kunita I, Harel R, Crofoot M, Mutinda M, Kamau M, Hassel JM, Murray S, Kawamura S, Matsumoto-Oda A

PloS one ( Public Library of Science (PLoS) )  18 ( 11 ) e0287357 - e0287357   2023 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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In environments with multiple predators, vulnerabilities associated with the spatial positions of group-living prey are non-uniform and depend on the hunting styles of the predators. Theoretically, coursing predators follow their prey over long distances and attack open areas, exposing individuals at the edge of the group to predation risk more than those at the center (marginal predation). In contrast, ambush predators lurk unnoticed by their prey and appear randomly anywhere in the group; therefore, isolated individuals in the group would be more vulnerable to predators. These positions of vulnerability to predation are expected to be taken by larger-bodied males. Moreover, dominant males presumably occupy the center of the safe group. However, identifying individuals at higher predation risk requires both simultaneous recording of predator location and direct observation of predation events; empirical observations leave ambiguity as to who is at risk. Instead, several theoretical methods (predation risk proxies) have been proposed to assess predation risk: (1) the size of the individual ‘unlimited domain of danger’ based on Voronoi tessellation, (2) the size of the ‘limited domain of danger’ based on predator detection distance, (3) peripheral/center position in the group (minimum convex polygon), (4) the number and direction of others in the vicinity (surroundedness), and (5) dyadic distances. We explored the age-sex distribution of individuals in at-risk positions within a wild baboon group facing predation risk from leopards, lions, and hyenas, using Global Positioning System collars. Our analysis of the location data from 26 baboons revealed that adult males were consistently isolated at the edge of the group in all predation risk proxies. Empirical evidence from previous studies indicates that adult male baboons are the most frequently preyed upon, and our results highlights the importance of spatial positioning in this.

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BATHING BEHAVIOUR IN SPOTTED HYENAS (CROCUTA CROCUTA) IN LAIKIPIA, KENYA: TWO OBSERVATIONAL CASES

Akiko Matsumoto-Oda

Journal of East African Natural History   110 ( 2 ) 87 - 92   2022.01 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Point of Care Blood Gas and Electrolyte Analysis in Anesthetized Olive Baboons (Papio anubis) in a Field Setting

Maureen W. Kamau, James M. Hassell, Ellie L. Milnes, Lee-Ann C. Hayek, Mathew M. Mutinda, Roi Harel, Akiko Matsumoto-Oda, Jennifer H. Yu, Dawn Zimmerman, Margaret Crofoot, Suzan Murray

International Journal of Primatology ( Springer Science and Business Media LLC )  42 ( 5 ) 667 - 681   2021.10 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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HEXACO, Dark Triad and altruism in daily life

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Pres Individ Differ   185   2021.10 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Influence of rainfall on sleeping site choice by a group of anubis baboons (Papio anubis).

Suire A, Isbell LA, Bidner LR, Shinoda Y, Akasaka M, Matsumoto-Oda A

American journal of primatology ( American Journal of Primatology )  83 ( 1 ) e23223   2021.01 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Capture, immobilization, and Global Positioning System collaring of olive baboons (Papio anubis) and vervets (Chlorocebus pygerythrus): Lessons learned and suggested best practices.

Isbell LA, Bidner LR, Omondi G, Mutinda M, Matsumoto-Oda A

American journal of primatology ( American Journal of Primatology )  81 ( 6 ) e22997   2019.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Complete rectal prolapse in wild anubis baboons (Papio anubis).

Taniguchi H, Isbell LA, Bidner LR, Matsumoto-Oda A

Journal of medical primatology ( Journal of Medical Primatology )  48 ( 3 ) 179 - 181   2019.06 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Expression Changes of Structural Protein Genes May Be Related to Adaptive Skin Characteristics Specific to Humans.

Arakawa N, Utsumi D, Takahashi K, Matsumoto-Oda A, Nyachieo A, Chai D, Jillani N, Imai H, Satta Y, Terai Y

Genome biology and evolution ( Genome Biology and Evolution )  11 ( 3 ) 613 - 628   2019.03 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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The role of sleeping sites in the predator-prey dynamics of leopards and olive baboons.

Bidner LR, Matsumoto-Oda A, Isbell LA

American journal of primatology ( American Journal of Primatology )  80 ( 12 ) e22932   2018.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Group size effects on inter-blink interval as an indicator of antipredator vigilance in wild baboons.

Matsumoto-Oda A, Okamoto K, Takahashi K, Ohira H

Scientific reports ( Scientific Reports )  8 ( 1 ) 10062   2018.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Rearing the African Grass Blue Butterfly Zizeeria knysna: Toward the Establishment of a Bioindicator in African Countries

IWATA Masaki, MATSUMOTO-ODA Akiko, OTAKI Joji M.

African Study Monographs ( 京都大学アフリカ地域研究資料センター )  39 ( 2 ) 69 - 81   2018.06 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Urbanization and environmental pollution have increasingly become important issues in African countries. For environmental risk management, it is important to conduct field surveys for potential surrogate species and establish their ecotoxicological rearing experiments. A rearing system for the pale grass blue butterfly Zizeeria maha (Lepidoptera, Lycaenidae) has been successfully employed in Japan for the assessment of human-living environments, including rural and urban areas. A phylogenetically related species, the African grass blue butterfly Zizeeria knysna, lives in human residential environments widely in African countries. Thus, this species is potentially useful as a similar bioindicator in Africa. This paper reports the establishment of a simple and economical rearing system for Zizeeria knysna as well as some morphological traits of the immature and adult stages of this species. Females were obtained in central Kenya and confined in a meshed cage where eggs were readily obtained. Hatched larvae were reared on a natural host plant Oxalis corniculata. The failure rate of eclosion from pupae to adults was 6.5%, and the reared adult individuals showed normal color patterns, demonstrating the high efficiency of this rearing system. The rearing method for Zizeeria knysna in the present study may provide a basis for future human-living environmental assessments in Africa.

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GPS-identified vulnerabilities of savannah-woodland primates to leopard predation and their implications for early hominins.

Isbell LA, Bidner LR, Van Cleave EK, Matsumoto-Oda A, Crofoot MC

Journal of human evolution ( Journal of Human Evolution )  118   1 - 13   2018.05 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Rearing the African grass blue butterfly Zizeeria knysna (Lepidoptera: Lycaenidae) and its morphological comparison among the genus Zizeeria: Toward the establishment of a bioindicator in African countries.

Iwata M, Matsumoto-Oda A, Otaki J

Afr Stu Monogr   39   69 - 81   2018 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Wound healing in wild male baboons: Estimating healing time from wound size.

Taniguchi H, Matsumoto-Oda A

PloS one ( PLoS ONE )  13 ( 10 ) e0205017   2018 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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GPS-identified, low-level nocturnal activity of vervets (Chlorocebus pygerythrus) and olive baboons (Papio anubis) in Laikipia, Kenya.

Isbell LA, Bidner LR, Crofoot MC, Matsumoto-Oda A, Farine DR

American journal of physical anthropology ( WILEY )  164 ( 1 ) 203 - 211   2017.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Objectives: Except for owl monkeys (Aotus spp.), all anthropoid primates are considered strictly diurnal. Recent studies leveraging new technologies have shown, however, that some diurnal anthropoids also engage in nocturnal activity. Here we examine the extent to which vervets (Chlor-ocebus pygerythrus) and olive baboons (Papio anubis) are active at night. Materials and Methods: We deployed GPS collars with tri-axial accelerometer data loggers on 18 free-ranging adult females: 12 vervets spread among 5 social groups, and 6 olive baboons spread among 4 groups. Their locations were recorded every 15 min, and their activity levels, for 3 s/min over 7.5 months. We also used camera traps that were triggered by heat and movement at seven sleeping sites. Results: Travel was detected on 0.4% of 2,029 vervet-nights involving 3 vervets and 1.1% of 1,109 baboon-nights involving 5 baboons. Travel was mainly arboreal for vervets but mainly terrestrial for baboons. During the night, vervets and baboons were active 13% and 15% of the time, respectively. Activity varied little throughout the night and appeared unaffected by moon phase. Discussion: Our results confirm the low nocturnality of vervets and olive baboons, which we suggest is related to living near the equator with consistent 12-hr days, in contrast to other anthropoids that are more active at night. Since anthropoid primates are thought to have evolved in northern latitudes, with later dispersal to tropical latitudes, our results may have implications for understanding the evolution of anthropoid diurnality.

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Testing socially mediated estrous synchrony or asynchrony in wild baboons

Yasuo Ihara, D. Anthony Collins, Ryo Oda, Akiko Matsumoto-Oda

BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY ( SPRINGER )  70 ( 11 ) 1921 - 1930   2016.11 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Females in some animal species have been suggested to synchronize or desynchronize their estrus cycles. This phenomenon may have a significant impact on the structure of animal societies because when there are more females simultaneously in estrus, even a dominant male is less able to defend them from other males. Previous attempts to detect non-random estrous cycles in primates have produced mixed results, and some of them have been criticized on the methodological grounds. We investigate whether wild female anubis baboons exhibit non-random estrous cycles using a larger dataset than previous studies. For a statistical analysis, we use a randomization procedure, taking a biasing effect of missing observations into consideration. Consistent with earlier studies on other species of baboons, our analysis does not find any evidence supporting estrous synchrony or asynchrony in anubis baboons.

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Two newly observed cases of fish-eating in anubis baboons.

Matsumoto-Oda A, Collins AD

LEBS   7   5 - 9   2016 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

How surviving baboons behaved after leopard predation: a case report

MATSUMOTO-ODA Akiko

Ａｎｔｈｒｏｐｏｌｏｇｉｃａｌ　Ｓｃｉｅｎｃｅ ( 日本人類学会 )  123 ( 1 ) 13 - 17   2015 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Predation has been an evolutionary force in primates, driving changes in their behavior, cognition, and numerous morphological characteristics. There is little evidence regarding the counter-strategies of primates to predation, because previous studies on primates have focused on the animals eaten rather than the animals that survive. I report a case of predation in which an adult male baboon was preyed on by a leopard in the early morning in the wild and describe how the surviving baboons behaved. Based on this report, I consider the counter-strategies of baboons to leopard predation, such as staying at the sleeping site, producing alarm calls, and shifting the sleeping site. Further information from other predation events is needed to understand the evolution of anti-predation behaviors.

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Activity Budgets and Rainfall Seasonality in a Wild Savanna Baboon (<i>Papio anubis</i>) Group

MATSUMOTO-ODA Akiko, PALOMBIT Ryne A

Primate Research ( Primate Society of Japan )  31 ( 2 ) 101 - 107   2015

Type of publication: Research paper (scientific journal)

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Activity budgets represent life styles, reproductive life points of females and patterns for habitat environment in animals. It is suggested that activity budget favor the worst environmental criteria and resting time becomes a buffer for increasing energy demand such as lactation. We studied the activity budgets of anubis baboons (<i>Papio anubis</i>) in the semi-arid Laikipia District of Kenya to investigate their behavioral strategies adapted for the dry months when available foods are poor. We found that 18.1 % of each day was devoted to feeding, 34.5 % to moving, 37.4 % to resting, and 10.0 % to participating in social interactions. Although this distribution of time did not change between the wet months and the dry months, the frequency of drinking water in the dry months was more than in the wet months. Anubis baboons switched their diet from insects in the wet months to herbaceous plants in the dry months. Comparison of the results with previous studies suggests that feeding time becomes short when group size is small.

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Sexually dimorphic preference for altruism in the opposite sex according to recipient.

Oda R, Shibata A, Kiyonari T, Takeda M, Matsumoto-Oda A

British journal of psychology (London, England : 1953) ( WILEY-BLACKWELL )  104 ( 4 ) 577 - 84   2013.11 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Sexual selection may affect human altruistic behaviour. Evolutionary psychology predicts that human mate preference reflects sexual selection. We investigated sex differences in preference for opposite-sex altruism according to recipient because the reasons for altruistic behaviour differ according to the relationship between actor and recipient. We employed the Self-Report Altruism Scale Distinguished by the Recipient, which was newly developed to evaluate altruism among Japanese undergraduates. We asked participants to evaluate preferences for each item based on the recipient of the altruistic behaviour (family members, friends or acquaintances, and strangers). Preference for opposite-sex altruism differed according to recipient, gender of the participant, and relationship type, and several significant interactions were observed among these factors. We suggest that whereas women use a potential partner's altruism towards strangers as a costly signal of their resource-holding potential when choosing a mate, they consider altruism towards family when they are in a long-term relationship to ensure that resources are not allocated to non-relatives.

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Ranging behavior of Mahale chimpanzees: a 16 year study.

Nakamura M, Corp N, Fujimoto M, Fujita S, Hanamura S, Hayaki H, Hosaka K, Huffman MA, Inaba A, Inoue E, Itoh N, Kutsukake N, Kiyono-Fuse M, Kooriyama T, Marchant LF, Matsumoto-Oda A, Matsusaka T, McGrew WC, Mitani JC, Nishie H, Norikoshi K, Sakamaki T, Shimada M, Turner LA, Wakibara JV, Zamma K

Primates; journal of primatology ( SPRINGER JAPAN KK )  54 ( 2 ) 171 - 82   2013.04 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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We have analyzed the ranging patterns of the Mimikire group (M group) of chimpanzees in the Mahale Mountains National Park, Tanzania. During 16 years, the chimpanzees moved over a total area of 25.2 or 27.4 km(2), as estimated by the grid-cell or minimum convex polygon (MCP) methods, respectively. Annually, the M group used an average of 18.4 km(2), or approximately 70 %, of the total home-range area. The chimpanzees had used 80 % of their total home range after 5 years and 95 % after 11 years. M group chimpanzees were observed more than half of the time in areas that composed only 15 % of their total home range. Thus, they typically moved over limited areas, visiting other parts of their range only occasionally. On average, the chimpanzees used 7.6 km(2) (in MCP) per month. Mean monthly range size was smallest at the end of the rainy season and largest at the end of the dry season, but there was much variability from year to year. The chimpanzees used many of the same areas every year when Saba comorensis fruits were abundant between August and January. In contrast, the chimpanzees used several different areas of their range in June. Here range overlap between years was relatively small. Over the 16 years of the study we found that the M group reduced their use of the northern part of their range and increased their frequency of visits to the eastern mountainous side of their home range. Changes in home-range size correlated positively with the number of adult females but not with the number of adult males. This finding does not support a prediction of the male-defended territory model proposed for some East African chimpanzee unit-groups.

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Human prosociality in altruism niche.

Oda R, Hiraishi K, Fukukawa Y, Matsumoto-Oda A

J Evol Psychol   9   283 - 293   2011 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Altruists are trusted based on non-verbal cues.

Oda R, Naganawa T, Yamauchi S, Yamagata N, Matsumoto-Oda A

Biology letters ( ROYAL SOC )  5 ( 6 ) 752 - 4   2009.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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The identification of altruists based on nonverbal cues might offer a solution to the problem of subtle cheating. Previous studies have indicated that the ability to discriminate altruists from non-altruists emerges during evolution. However, behavioural differences with regard to social exchanges involving altruists and non-altruists have not been studied. We investigated differences in responses to videotaped altruists and non-altruists with the Faith Game. Participants tended to entrust real money to altruists more than to non-altruists, providing strong evidence that cognitive adaptations evolve as counter-strategies to subtle cheating.

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Cross-cultural perceptions of facial resemblance between kin.

Alvergne A, Oda R, Faurie C, Matsumoto-Oda A, Durand V, Raymond M

Journal of vision ( ASSOC RESEARCH VISION OPHTHALMOLOGY INC )  9 ( 6 ) 23.1 - 10   2009.06 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Humans use facial comparisons to identify their relatives and adjust their behavior accordingly. However, the mechanisms underlying the assessment of facial similarities are poorly known. Here, we investigate the role of exposure to particular faces for the detection of facial similarities by asking judges to detect parent-child pairs using faces from different origins. In a first phase, French and Senegalese judges assessed facial resemblance in French and Senegalese families. In a second phase, Senegalese judges who had immigrated to France, as well as French and Senegalese stationary judges, were asked to rate a second set of Senegalese and French families. The judges showed no differences in their ability to detect parent-child pairs in French and Senegalese families in both the first and second phases. For judges who changed their country of residence, the answer time and duration of stay in the new country were not associated with correct assignment rates. Our results suggest that exposure has a limited role in the ability to process facial resemblance in others, which contrasts with facial recognition processing. We also discuss whether processing facial similarities is a by-product of the facial recognition system or an evolved ability to assess kinship relationships.

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Altruism can be assessed correctly based on impression．

Oda R, Yamagata N, Yabiku Y, Matsumoto-Oda A

Hum Nat   20   331 - 341   2009 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Estrus cycle asynchrony in wild female chimpanzees, Pan troglodytes schweinfurthii

Akiko Matsumoto-Oda, Miya Hamai, Hitosige Hayaki, Kazuhiko Hosaka, Kevin D. Hunt, Eiiti Kasuya, Kenji Kawanaka, John C. Mitani, Hiroyuki Takasaki, Yukio Takahata

Behavioral Ecology and Sociobiology   61 ( 5 ) 661 - 668   2007.03 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Although estrous synchrony has been reported in a number of mammalian species, most often among primates, methodological and analytical problems make it difficult to interpret these results. We developed a novel estrous synchrony index and employed a randomization procedure to analyze long-term observations of female chimpanzee (Pan troglodytes schweinfurthii) estrous cycles at the Mahale Mountains National Park, Tanzania. Our results revealed that female chimpanzees at Mahale avoid synchronizing their estrous periods with each other. We also found that birthrates decreased as the breeding sex ratio increased. We suggest that estrous asynchrony decreases female-female competition for mates. Asynchrony may also reduce the potential for male sexual coercion by nonpreferred mating partners. © 2007 Springer-Verlag.

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Sniffing behaviors in Mahale chimpanzees.

Matsumoto-Oda A, Kutsukake N, Hosaka K, Matsusaka T

Primates; journal of primatology ( SPRINGER TOKYO )  48 ( 1 ) 81 - 5   2007.01 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Although it is difficult for observers to determine how non-human primates use olfaction in a natural environment, sniffing is one clue. In this study, the sniffing behaviors of wild chimpanzees were divided into six categories, and sex differences were found in most categories. Males sniffed more frequently than females in sexual and social situations, while females sniffed more often during feeding and self-checking. Chimpanzees sniffed more frequently during the dry season than during the wet season, presumably due to the low humidity. This suggests that the environment affects olfactory use by chimpanzees and that chimpanzees easily gather new information from the ground via sniffing.

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Does an altruist-detection cognitive mechanism function independently of a cheater-detection cognitive mechanism? Studies using Wason selection tasks

Ryo Oda, Kai Hiraishi, Akiko Matsumoto-Oda

EVOLUTION AND HUMAN BEHAVIOR ( ELSEVIER SCIENCE INC )  27 ( 5 ) 366 - 380   2006.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Subjects performed four deontic Wason selection tasks in three experiments to investigate possible commonalities in people's performance in making logical inferences in social contexts. These tasks tested sensitivity to another party being an altruist, cheater or willing to share a resource and following a precaution rule in the context of danger. The results indicated no significant association between performance on the altruist detection and the cheater detection tasks. This result suggests that whatever the nature of the altruist-detection algorithm, it functions independently of the cheater-detection algorithm. The results also indicated significant associations between the cheater-detection task and the resource-sharing task. Possible mechanisms and functions of social intelligence suggested by these results are discussed. (c) 2006 Elsevier Inc. All rights reserved.

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Effects of belief in genetic relatedness on resemblance judgements by Japanese raters

R Oda, A Matsumoto-Oda, O Kurashima

EVOLUTION AND HUMAN BEHAVIOR ( ELSEVIER SCIENCE INC )  26 ( 5 ) 441 - 450   2005.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Kinship is a key element in the recognition of human genetic relatedness. People use phenotype matching, especially resemblance with respect to facial features, to recognize kin. Bressan and Dal Martello (2002) assessed the effects of actual and assumed genetic relatedness on resemblance ratings made by Italian adults. We replicated their experiment using Japanese individuals as our stimuli and raters. To further assess the processes underlying resemblance ratings, we also compared reaction times. As in previous research, belief in genetic relatedness strongly affected resemblance ratings, but the direction of the cognitive bias was different. Analysis of reaction times indicated that participants took shorter time to assess the resemblance of unrelated pair members than related ones. (c) 2005 Elsevier Inc. All rights reserved.

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Proximity and estrous synchrony in Mahale chimpanzees.

Matsumoto-Oda A, Kasuya E

American journal of primatology ( WILEY-LISS )  66 ( 2 ) 159 - 66   2005.06 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Since McClintock [Nature 229:244-255, 1971] first reported menstrual. synchrony in women, a number of studies have reported similar phenomena. Many researchers have suggested that one of the proximate factors leading to synchrony is spatial proximity among females (e.g., close friends or roommates). However, most studies on menstrual synchrony have been conducted in limited spaces, and it remains to be determined whether controlled environments, such as those used in experiments, actually exist in the wild. In this study, we analyzed the relationship between proximity and estrous synchrony using data from wild female chimpanzees at Mahale, Tanzania. In the cycling females, we observed two pairs that spent a large amount of time together. We compared the estrous synchrony indices (ESIs) between these two pairs and the other females. Our results showed that the ESIs of the high-proximity pairs did not differ from those of other pairs. Am. J. Primatol. 66:159-166, 2005. (c) 2005 Wiley-Liss, Inc.

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“Intentional” control of sound production found in leaf-clipping display of Mahale chimpanzees.

Matsumoto-Oda A, Tomonaga M

J Ethol   23 ( 2 ) 109 - 112   2005 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Extraordinarily low bone mineral density in an old female chimpanzee (Pan troglodytes schweinfurthii) from the Mahale Mountains National Park.

Gunji H, Hosaka K, Huffman MA, Kawanaka K, Matsumoto-Oda A, Hamada Y, Nishida T

Primates; journal of primatology ( SPRINGER-VERLAG TOKYO )  44 ( 2 ) 145 - 9   2003.04 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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We examined bone mineral density (BMD) of the femoral neck and lumbar vertebrae of four chimpanzee skeletons from Mahale Mountains National Park, Tanzania, and four captive ones, with a dual energy X-ray absorptiometer. The BMD of Wansombo, an old female chimpanzee from Mahale, was remarkably lower than the mean of the other six younger adult female chimpanzees and categorized as osteoporosis. Posture, locomotion, and trunk-sacral anatomy of chimpanzees may have prevented fractures in Wansombo, whose BMD was below human osteoporosis criteria.

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Demography, female life history, and reproductive profiles among the chimpanzees of Mahale.

Nishida T, Corp N, Hamai M, Hasegawa T, Hiraiwa-Hasegawa M, Hosaka K, Hunt KD, Itoh N, Kawanaka K, Matsumoto-Oda A, Mitani JC, Nakamura M, Norikoshi K, Sakamaki T, Turner L, Uehara S, Zamma K

American journal of primatology ( WILEY-LISS )  59 ( 3 ) 99 - 121   2003.03 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Demography provides critical data to increase our understanding of the evolution, ecology, and conservation of primate populations. The chimpanzees of the Mahale Mountains National Park, Tanzania, have been studied for more than 34 yr on the basis of individual identification and standardized attendance records. From this long-term study, we derived the following demographic data: The major cause of death was disease (48%), followed by senescence (24%) and within-species aggression (16%). Fifty percent of Mahale chimpanzees died before weaning. The median ages of female life history variables were: first maximal swelling, 10.0 yr (n = 5); emigration, 11.0 yr (n = 11); and first birth, 13.1 yr (n = 5). The median period of adolescent infertility was 2.8 yr (n = 4) when calculated from the age at immigration to that at first birth. Female fecundity was highest between 20 and 35 yr of age, with an annual birth rate of 0.2. Twenty-six females that were observed from a young age (1013 yr) to death at various ages (15-40 yr) gave birth to an average of 3.9 and weaned an average of 1.4 offspring. Twenty-five females that were observed from middle age (18-33 yr) to death in older age (31-48) gave birth to an average of 2.7 and weaned an average of 2.0 offspring. The post-reproductive lifespan for female chimpanzees was defined as the number of years that passed from the year when the last offspring was born to the year when the female died, minus 5. Twenty-five percent of old females had a post-reproductive lifespan. The interbirth interval after the birth of a son ((x) over bar = 72 mo) tended to be longer than that after the birth of a daughter ((x) over bar = 66 mo). The extent of female transfer, which is a rule in chimpanzees, is influenced by the size and composition of the unit group and size of the overall local community. (C) 2003 Wiley-Liss, Inc.

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Vaginal fatty acids produced by chimpanzees during menstrual cycles.

Matsumoto-Oda A, Oda R, Hayashi Y, Murakami H, Maeda N, Kumazaki K, Shimizu K, Matsuzawa T

Folia primatologica; international journal of primatology   74 ( 2 ) 75 - 9   2003.03 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Low BMD old female chimpanzee skeleton from the Mahale Mountains National Park, Tanzania

Gunji H, Hosaka K, Huffman M, Kawanaka K, Matsumoto-Oda A, Hamada Y, Nishida T

Primates 44 (2): 145-149.     2003 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

The four chimpanzee skulls collected in the Mahale Mountains, Tanzania

D Shimizu, H Gunji, H Hashimoto, K Hosaka, MA Huffman, A Matsumoto-Oda, K Kawanaka, T Nishida

ANTHROPOLOGICAL SCIENCE ( ANTHROPOLOGICAL SOC NIPPON )  110 ( 3 ) 251 - 266   2002.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Morphological and osteological data taken from chimpanzee skeletal materials gathered at chimpanzee research sites are accompanied by life history data (e.g. diet, environment of habitat, sexual activity and social relationship). Unfortunately morphological and osteological studies of chimpanzee skeletal remains from long-term field research projects are rare (Yasui and Takahata, 1983, an infant of P. t. schweinfurthii from Mahale mountains National Park, Tanzania; Morbeck and Zihlman, 1989, ten individuals of P. t. schweinfurthii from Gombe National Park, Tanzania; Matsuzawa et al. 1990, a young male of P. t. verus from Bossou, Guinea). This study described basic morphological and osteological information (i.e. linear measurements of skulls and dentitions, dental wear, notable pathological traits) taken from four free-ranging chimpanzee skulls (Pan troglodytes schweinfurthii) that were collected from the Mahale Mountains National Park, Tanzania. The dental wear is then discussed in relation to the life history variables of individual chimpanzees.

Behavioral seasonality in Mahale chimpanzees.

Matsumoto-Oda A

Primates; journal of primatology   43 ( 2 ) 103 - 17   2002.04 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Facial resemblance of Japanese children to their parents

R Oda, A Matsumoto-Oda, O Kurashima

JOURNAL OF ETHOLOGY ( SPRINGER-VERLAG TOKYO )  20 ( 2 ) 81 - 85   2002 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Facial resemblance between parents and their children could be an indicator of genetic relationship, and selective pressure could bias the resemblance of appearance. We assessed the degree of resemblance of 38 Japanese children (3-6 years old) to each of their parents using photographs. We asked nonrelatives to assess which of the parents each child resembled, manipulating indications of the sex of the children. Variance in the degree of resemblance between the children and their fathers was very large. Although the basic facial appearance of each parent can be reflected in each child with 50% probability, the children did not equally show the facial characteristics of each parent at the individual level. The indication of sex had no significant effect on the assessment of resemblance. On the other hand, a questionnaire given to the assessors revealed that, as children, they tended to be said to resemble the opposite-sex parent. This result indicates that alleged resemblance does not reflect an actual condition but rather might have cultural meaning.

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Activity budgets of wild female chimpanzees in different reproductive states

A Matsumoto-Oda, R Oda

JOURNAL OF ETHOLOGY ( JAPAN ETHOL SOC )  19 ( 1 ) 17 - 21   2001 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Activity budgets of wild female chimpanzees (Pan troglodytes schweinfurthii) when lactating were compared with those during estrus and anestrus. Five anestrous females, seven estrous females, and three lactating females in Mahale Mountains National Park, Tanzania, were the subject of focal sampling. Time spent for feeding, resting, and moving was examined. For each of these three categories of activity, there was no significant difference of time spent for each activity between lactating females and either estrous or anestrous females. The females spent about 30% of their daytime feeding, about 40% resting, and about 30% moving. One of the reasons for the lack of difference might be the type of parties that females attended when they were observed. In most cases, the females were seen in large bisexual parties. Although lactating females are expected to need more nutrition than cycling females and this might affect their activity budget, the party type they attended might also affect the budget.

Predation of mammals by the chimpanzees of the Mahale Mountains, Tanzania

K Hosaka, T Nishida, M Hamai, A Matsumoto-Oda, S Uehara

ALL APES GREAT AND SMALL, VOL 1: AFRICAN APES ( KLUWER ACADEMIC/PLENUM PUBL )    107 - 130   2001 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Preliminary study of feeding competition between baboons and chimpanzees in the Mahale Mountains National Park, Tanzania.

Matsumoto-Oda A, Kasagura MB

Afr Stu Monogr   21   147 - 157   2000 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Female choice in the opportunistic mating of wild chimpanzees (Pan troglodytes schweinfurthii) at Mahale

A Matsumoto-Oda

BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY ( SPRINGER VERLAG )  46 ( 4 ) 258 - 266   1999.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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For female chimpanzees (Pan troglodytes schweinfurthii) in the Mahale Mountains National Park? Tanzania, the most common mating pattern is opportunistic. In such opportunistic matings, females copulated promiscuously but not randomly. This study describes female mate choice during 1-year observation of six females who exhibited regular genital-swelling cycles. During the study period, 169 opportunistic matings and four restrictive matings were recorded over the course of 51 days. As female estrus progressed, mating frequency and the number of adult male mating partners increased, although the number of potential mating partners did not change. Criteria of female choice examined were the direction and consent/rejection of courtship, proximity maintenance, and female grooming. Adult-male courtships were successful more often than those of adolescent males. During the earlier phase of estrus, females copulated rather promiscuously with many males. But during the later phase of estrus when the likelihood of conception is expected to be highest, they copulated repeatedly with high-ranking adult males. There was a positive correlation between female grooming frequency and mating frequency when the likelihood of conception was greatest. Female chimpanzees are thought to choose high-ranking males as fathers of their offspring. Moreover, female chimpanzees may adopt one or both of two mating strategies, i.e., a many-male strategy and a best-male strategy.

Nutritional aspects of fruit choice by chimpanzees

A Matsumoto-Oda, Y Hayashi

FOLIA PRIMATOLOGICA ( KARGER )  70 ( 3 ) 154 - 162   1999.05 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Mahale chimpanzees: Grouping patterns and cycling females

A Matsumoto-Oda

AMERICAN JOURNAL OF PRIMATOLOGY ( WILEY-LISS )  47 ( 3 ) 197 - 207   1999 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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The social system of chimpanzees (Pan troglodytes schweinfurthii) is characterized by the fission-fusion of social groups. Several studies have reported that females are less gregarious than males. In the current study, adult female gregariousness depended on their reproductive state. Noncycling adult females (pregnant, lactating, or post reproductive) were observed in large bisexual parties less often than cycling adult females. On the other hand, cycling adult females were observed in large bisexual parties as often as males, regardless of their estrous state. More males were in parties that included cycling adult females with maximal genital swelling (estrous females) than in parties without them. Moreover, a bisexual party including more estrous females contained more males. These results suggest that large bisexual parties of chimpanzees are constructed by a dual mechanism. First, cycling adult females are attracted to parties that consist of the top ranking male and large numbers of adult and adolescent males. Second, adult and adolescent males that did not belong to parties originally are attracted by estrous females and join them. Thus, in Mahale Mountains National Park, Tanzania, bisexual parties of chimpanzees can be characterized as "parties for reproduction." Am. J. Primatol, 47:197-207, 1999. (C) 1999 Wiley-Liss, Inc.

Factors affecting party size in chimpanzees of the Mahale mountains

A Matsumoto-Oda, K Hosaka, MA Huffman, K Kawanaka

INTERNATIONAL JOURNAL OF PRIMATOLOGY ( KLUWER ACADEMIC/PLENUM PUBL )  19 ( 6 ) 999 - 1011   1998.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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We studied factors affecting party size and composition of wild chimpanzees at Mahale (M group) over an 11-month period Parties with 1-5 individuals were most frequent (37.8%; 153/405 parties), they included 94.7% of all male pm-ties (n = 76) and 81.3% of all female parties (n = 75). The median of monthly values was the standard for analysis. We divided the year into four period based on the median size of monthly bisexual parties (30.9 individuals; includes both males and females): monthly bisexual party sizes were larger in May-June (period II) and October-January (period IV) and smaller in February-April (period I) and July-September (period III). Only bisexual parties changed in size with period. The number of fruit items (=species) eaten was fewer in periods II and IV when abundance per item appeared to be great. The sizes of bisexual parties, which included cycling females with maximal anogenital swelling, were larger, and their representation (%) in all bisexual parties was greater in period III and IV. The numbers of both cycling females and cycling females with maximal anogenital swelling were also larger in period III and IV The percentage of cycling females with maximal anogenital swelling was greater in period II and III. The results of this study and those of Nishida (1979) suggest that seasonal variation in party size of Mahale chimpanzees maintains a relatively consistent annual cycle. The factors assumed to affect party sizes are fruit availability and the presence of cycling females with maximal anogenital swelling.

Injuries to the sexual skin of female chimpanzees at Mahale and their effect on behaviour

A Matsumoto-Oda

FOLIA PRIMATOLOGICA ( KARGER )  69 ( 6 ) 400 - 404   1998.11 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Changes in the activity budget of cycling female chimpanzees

A Matsumoto-Oda, R Oda

AMERICAN JOURNAL OF PRIMATOLOGY ( WILEY-LISS )  46 ( 2 ) 157 - 166   1998 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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This study is a preliminary report on the time allocated to various activities by female wild chimpanzees (Pan troglodytes schweinfurthii) during their sexual cycle. Cycling females with maximal tumescence (estrous females) tended to spend more time moving than cycling females with quiescent sexual skin (anestrous females). Although there was no statistically significant decrease in any specific activity that corresponded to the increase in time spent moving, feeding time did decrease in four of the five females. The frequency of approach by females toward males and the frequency of approach by males toward females significantly increased when females were in estrus. Direct aggression by males occurred more frequently toward estrous females than toward anestrous females. The copulation frequency and the frequency of approach to males was not significantly correlated with the increase in time spent moving. There was a high but not significant correlation between the time spent moving and the frequency of direct aggression by males toward females. Mating effort, feeding competition, male aggression, and other possible reasons that might explain the increase in moving time are discussed. (C) 1998 Wiley-Liss, Inc.

Self-suckling behaviour by a wild chimpanzee

A MatsumotoOda

FOLIA PRIMATOLOGICA ( KARGER )  68 ( 6 ) 342 - 343   1997.11 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

First record of a twin birth in chimpanzees of the Mahale Mountains National Park, Tanzania.

Matsumoto-Oda A

Afr Stu Monogr   16   159 - 164   1995 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)