Behavioural development has received little attention in primates, despite having important influences on infant mortality, interbirth intervals, and therefore, growth of populations. Gorillas have long developmental periods, exhibit strong maternal bonds and integrate into intricate social systems, making them an ideal species in which to investigate non-human primate development. Gorillas exist across a range of habitats, and differences in behaviour, both within and between species reflect socioecological differences, for example, in the availability and distribution of food. Consequently, by using gorillas as a model, opportunities also exist to investigate environmental constraints on the development of independence. This study provides the first detailed analysis, with reference to ecological factors, of the development of behavioural skills and relationships in wild western lowland gorillas (Gorilla gorilla gorilla). Behavioural development of western lowland gorillas is then compared with published accounts of development in mountain gorillas (Gorilla beringei beringei) to determine the extent to which differing ecology influences behaviour. The study was conducted at Mbeli Bai in the Republic of Congo, a large, marshy clearing, visited by gorillas predominantly for feeding purposes. Data were collected using scan, focal, all-occurrence and ad libitum sampling methods from 58 gorillas below 8 years of age. Spatial relationships, suckling, and the nature of interactions involving immature individuals were analysed. The distribution of time between different behaviours by immatures, and the development of independent feeding and travelling behaviour was also investigated, and all were tested for differences as a result of immature age, sex and social group, or the mother's parity. Towards the end of infancy, individuals showed competent feeding behaviour in the bai. However, western lowland gorillas were not weaned until the juvenile period, and until this time, close association was common between mothers and offspring. With increasing independence from the mother there was limited investment in relationships with other individuals, and instead, a greater emphasis was placed on developing skills through play, alloparenting and agonistic interactions. When results were compared with those of mountain gorillas, there was evidence of increased investment in relationships, particularly with the silverback, by immature mountain gorillas, which was assumed to reflect lower rates of natal dispersal by mountain gorillas, and the greater likelihood that relationships with individuals in the natal group could prove useful in the future. Suckling and close proximity to the mother continued until later ages in western lowland gorillas, resulting in clear differences between them mountain gorillas in the duration of investment by mothers. More frugivorous western lowland gorillas required increased levels of investment by the mother before independence could be achieved, demonstrating the effect that resource availability can have on behavioural development in species where resources are widely and unpredictably dispersed.

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京都大学 / 新制・課程博士 / 博士(地域研究) / 甲第23302号 / 地博第283号 / 新制||地||108(附属図書館) / 京都大学大学院アジア・アフリカ地域研究研究科アフリカ地域研究専攻 / (主査)教授 山越 言, 教授 大山 修一, 准教授 佐藤 宏樹, 助教 木下 こづえ / 学位規則第4条第1項該当 / Doctor of Area Studies / Kyoto University / DGAM

Post-conflict behaviors, including reconciliation, redirected aggression, and consolation, have been observed in several primate and non-primate species. These behaviors are thought to help re-establish rates of affiliation and tolerance to baseline levels, by terminating the victims stress response, and reducing the social tension created by conflict. Post-conflict behavior was examined in two groups (N = 13) of captive western lowland gorillas, a species for which no previous conflict resolution data exist. The post-conflict/matched-control method was used to observe the groups at Zoo Atlanta. Analyses of 223 conflicts (using chi-square, Wilcoxon signed ranks, and Kolmogorov-Smirnov tests) showed significantly more affiliation between former opponents after a conflict when compared to control periods, indicating reconciliation. Results also showed significantly more affiliation between the victim and a third-party after a conflict, indicating consolation. Both solicited and unsolicited consolation were observed. Instances of redirected aggression were very few, and thus not included in the analyses. The majority of the affiliative interactions were social proximity, which suggests that unlike most nonhuman primates, proximity, rather than physical contact, may be the main mechanism for resolving conflicts in western lowland gorillas. Post-conflict behavior was not uniform throughout the groups, but rather varied according to dyad type (for instance, adult-adult, juvenile-juvenile, adult-juvenile, etc.). Effects of kinship and the intensity of aggression during a conflict on post-conflict behavioral patterns were analyzed.

This thesis uses a case study of mountain gorilla conservation in Rwanda and the DRC to explore how diverse connections and disconnections influence idea circulation and disseminate different forms of inclusion and exclusion of particular people and groups. It is embedded within a theoretical framework that brings together three bodies of literature on non-governmental organisations (NGOs), transnational networks and ideational power to ask questions about network interactions and what they mean in terms of idea circulation. The thesis addresses three research questions: What do transnational networks look like on the ground; what do (dis)connections look like and what do they mean in terms of idea circulation, inclusion and exclusion; and (how) do transnational networks operate to include and circulate the ideas of more marginalised groups in society? This thesis presents results from a survey of the work of 281 conservation NGOs in sub-Saharan Africa, which maps out the institutional context of mountain gorilla conservation and raises questions about the interactions, equality and inclusiveness of the sector. Having identified mountain gorilla conservation as a suitable case study for this research, the thesis explores the political and environmental history of the Virungas, looking at how the two interact and influence (dis)connections. Using data gathered from semi-structured interviews, this thesis introduces the key actors, structures and processes involved in mountain gorilla conservation in Rwanda and the DRC and explores the connections between them. It shows how connections based on perceptions of expertise, staff movement and the professional and social circles people move in cause certain ideas to be respected and circulated, whilst other people and their ideas are ‘accidentally’ excluded. At the same time ‘strategic’ disconnections, which result from personal and organisational conflicts, can prevent idea circulation and lead to project duplication in some areas and a lack of projects in others. The thesis also examines NGO and state claims that ‘the idea (for interventions) came from the community’. It argues that, with exceptions, in a context of ‘sensitisation’ of communities to conservation and a complex political history, NGOs and states often define community ‘ideas’ themselves and do not typically have processes in place to foster local ideas, potentially excluding some of the more marginalised groups in society.

付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院 / 京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22878号 / 理博第4644号 / 新制||理||1668(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 足立 幾磨, 准教授 Michael Alan Huffman, 教授 高田 昌彦 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

No description available.

No description available.

Comprendre l'émergence et la propagation des maladies infectieuses chez les animaux sauvages est devenue une priorité en santé publique et en conservation. En combinant la collecte de données et le développement de modèles épidémiologiques, cette thèse s'est focalisée sur la compréhension de deux phénomènes clés: (i) étudier comment l'hétérogénéité au niveau des individus, des groupes, de la population et de l'environnement influence la propagation de parasites et (ii) quantifier la transmission de bactéries résistantes aux antibiotiques depuis l'homme vers les animaux sauvages dans trois aires protégées d'Afrique (Tsaobis NP- Namibie, Lopé NP-Gabon et Dzanga-Ndoki NP- République Centrafricaine). Les principaux résultats de ce travail montrent que : (1) De multiples facteurs incluant la température, la pluie, l'utilisation du territoire, le genre, l'âge et la condition physique influencent la richesse spécifique de parasites gastro-intestinaux chez le babouin chacma, (2) Les contacts entre animaux autour des points d'attractions de l'habitat peuvent influencer de manière importante la propagation spatio-temporelle d'une maladie, (3) La transmission d'entérobactéries résistantes semble avoir lieu depuis les humains ou le bétail vers les animaux sauvages dans des zones où le contact entre ces populations est élevé, (4) Le gradient de densité de gorilles produit par la chasse peut générer une augmentation de prévalence d'un parasite avec la distance au point d'introduction. Les conclusions de ce travail ouvrent de nouvelles possibilités pour l'étude des maladies émergentes chez les animaux sauvages. / Understanding the emergence and spread of infectious disease in wild animal populations has become an important priority for both public health and animal conservation. Combining the collection of empirical data with the development of epidemiological models, this thesis focuses on understanding two key issues of wildlife epidemiology: (i) how heterogeneity at the individual, group, population and landscape level affects parasite spread (ii) investigating whether transmission of antibiotic resistant bacteria from humans to wildlife is occurring within three protected areas of Africa (Tsaobis NP-Namibia, Lope NP-Gabon and Dzanga-Ndoki NP-Central African Republic). The main findings of this work indicated that: (1) multiple-scale factors including temperature, rainfall, home range use, sex, age and body condition influence gastro-intestinal parasite richness among wild baboons; (2) animal contacts around ‘habitat hotspots' can substantially influence the spatio-temporal dynamics of a disease; (3) antibiotic resistant enterobacteria seem to be spreading from humans/livestock to wildlife when the territory overlap between these two populations is expected to be high; (4) gradients in gorilla density created by bushmeat hunting can reverse the expected pattern of decreasing parasite prevalence with distance to human-spillover. The conclusions of this work open new possibilities for studying the mechanisms explaining the spread of emerging infectious diseases among wild animals.

Based on recognized life history traits and ecology, zoos strive to house their gorillas (Gorilla gorilla gorilla) in mixed-sex groups with one mature male or silverback, multiple females, and their offspring. However, successful captive breeding programs and a nearly 50:50 birth sex ratio has created the need to house surplus males in solitary conditions or all-male groups. It is commonly believed that male western gorillas will not tolerate one another in the presence of females; however, multi-male, mixed-sex groups have been observed in the wild. For this reason, some zoos have begun experimenting with this scenario. At the time of data collection, only four of the 51 institutions housing gorillas in the North American Species Survival Plan® population housed multi-male, mixed sex groups. Chapter one documents the activity budgets of two of these multi-male groups and compares them to those of two traditional family troops. Overall behavior repertoire was similar between group type, though more locomoting and aberrant behaviors were exhibited by individuals in the multi-silverback groups. Interaction between the silverbacks varied greatly between the multi-male groups which suggests there could be multiple models of success for these groups. However, further insight is needed to determine why some multi-male groups are successful while others are not. Therefore, the second chapter outlines the results of a multi-institutional survey which covered the recent history of multi-male, mixed-sex groups in North American zoos. The goal of the survey was to determine potential factors associated with silverback compatibility. Results indicate that there is an association between successful multi-male, mixed-sex groups and some life history factors including the relatedness of the males, their rearing histories, and the time at which they were introduced. This research offers insight into a potential gorilla social assemblage that has been underutilized in zoo settings.