2000 Fiscal Year Final Research Report Summary
Ecological and Genetical Variation of Baboon Social System
| Project/Area Number |
10041174
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
生態
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| Research Institution | MIYAZAKI UNIVERSITY |
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Principal Investigator |
IWAMOTO Toshitaka Miyazaki Univ., Faculty of Education & Culture, Professor, 教育文化学部, 教授 (40094073)
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| Co-Investigator(Kenkyū-buntansha) |
DOI Teruo Kyushu Univ., Faculty of Science, Assistant Professor, 理学部, 助手 (80091247)
MORI Akio Kyoto Univ., Primate Research Institute, Associate Professor, 霊長類研究所, 助教授 (50027504)
SHOTAKE Takayoshi Kyoto Univ., Primate Research Institute, Professor, 霊長類研究所, 教授 (00003103)
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| Project Period (FY) |
1998 – 2000
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| Keywords | hamaryas baboon / gelada baboon / adaptive diversion / phylogenical evolution / social structure / population genetics / feeding ecology / infanticide |
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| Research Abstract |
This project aimed to reconstruct the history of socio-ecological diversion of baboon species through adaptation to different habitat in Horn of Africa and Arabian Peninsula. We tried to relate the variation of their social structure to the ecological constraints that may have worked during the diversion. Both of gelada baboon and hamadryas baboon are known to have multi-layered social system, but matrilineal in gelada baboon and patrilineal in hamadryas baboon. Therefore, our study intended to find what factor has produced such kind of social system in both species. We employed genetic analyses to know the deviation time of each baboon species and to understand kinship as well as field observations of ecology and behaviors.
An isolated small population of gelada baboons inhabiting southern plateau of Great Rift Valley (GRV) was suggested to have some different social and ecological features from conspecifics on the northern plateau of GRV.We also revealed that rearrangements of unit co
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mposition occurred at a high rate and their social structure deviates from the typical matrilineal one. The variation could be related to the low food/water availability and high predation pressures in the southern habitat.
Only a preliminary study had been conducted on the ecology and social structure of hamadryas baboons in Saudi Arabia. We conducted intensive studies on two populations of hamadryas baboons in Saudi Arabia. Although the social structure was basically same as that have been reported from Africa, it has been modified to some extent by the desert specific geographical features and high degree of commensalisms. We observed some proximate cases of infanticide in our field. However, we suggested that the so-called gene of infanticide does not exist, because we could relocate the aggressive behaviors causing infanticide into a series of popular herding behaviors used by males normally. Based on the field observations and genetic analysis for kin-relationships among members in units, we obtained a result that the change of alpha male in a unit occurs at a fairly high rate. Considering the frequent rearrangement rate in gelada baboon as mentioned above, we can suggest a similarity of grouping rules between gelada baboons in the southern plateau, Ethiopia, and hamadryas baboons in Saudi Arabia.
Based on population genetic analyses, we estimated the diversion time of northern and southern population of gelada baboon as 3.5 million years ago. We presented a hypothesis for the specification process of hamadryas baboon that a common ancestor of anubis and hamadryas baboons had evolved into the hamadryas species in Arabian Peninsula, and it spread back to Africa. This idea is opposite from the present belief.
Thus, this project could obtain several important findings that change the present beliefs on the adaptive divergence and socio-ecological features of two baboon species. Less
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