ボッソウ・ニンバの野生チンパンジー : 2003年の流行病による大量死と「緑の回廊」計画

The present paper reports the death of wild chimpanzees through a flu-like epidemic at Bossou, Guinea, West Africa. The community at Bossou has been studied continuously since 1976. Records from the past 28 years show that the number of chimpanzees in the Bossou community has been relatively stable, at around 20 individuals. In late November 2003, chimpanzees at Bossou began to cough. Within a month, five chimpanzees died: two very old females, one adolescent male, and two infants. The mothers of the two dead infants continued to carry the corpses, which eventually mummified. One mother used a stick to chase flies away from the dead infant's body in addition to using her hands. The transportation of infants' mummified bodies may be yet another example of cultural behavior unique to this community. A 12 year-old young mother, who lost her first offspring in this epidemic, remained with the community for two months following the death of the infant, after which she disappeared, most likely immigrating to a neighboring community. We inspected the year-by-year change of age-sex composition in the Bossou community. This revealed that the proportion of old members gradually increased while many young members immigrated. Such a gradual change in the population in addition to the epidemic suggests that this community is in serious danger. The paper also introduces our conservation efforts to attempt to save this important community: the "Green corridor project" which entails the planting of trees in the surrounding savanna in order to create a passage between Bossou and the Nimba Mountains, 4 km away. This might be a model case of connecting chimpanzee habitats that have become isolated through increasing human activity, a very common problem in West Africa.