Department of Anthropology, University College London (UCL), London, UK.
Gene Bank of Primates and Primate Genetics Laboratory, German Primate Center (DPZ), Leibniz Institute for Primate Research, Göttingen, Germany.
Primates. 2021 Mar;62(2):253-265. doi: 10.1007/s10329-020-00884-5. Epub 2021 Feb 2.
Between 1966 to 1969, Bernhard Grzimek (Frankfurt Zoological Society, FZS) introduced chimpanzees (Pan troglodytes) previously held in European institutions to Rubondo Island in Lake Victoria in Tanzania. Earlier publications report various numbers of released animals and that all founders originated from West Africa. We revise these assumptions through consultation of archived FZS records and genetic analyses of surviving descendants. Accordingly, 17 chimpanzees were transported to Africa in four waves, with male-female ratios of 3:8, 1:0, 1:0 and 2:2; one female died in transit. Thus, 16 chimpanzees were released in total. FZS and studbook records allocate a West African provenance to only 19% of the founders and a generic "Africa" origin to 56%. Still, studbook records render it unlikely that any of the founders were captive-born. In addition, our genetic analyses based on biological samples from the current descendants trace the geographical origin of their ancestors back to West Africa (P. t. verus) and Central Africa (P. t. troglodytes). Based on counts of individuals and night nests, we estimate that the population, since 1969, grew to around 35 individuals in 2014 (annual increase 3.3%). Thus, chimpanzees released onto a large forested island free from predators or hunting pressure, habitat destruction and conspecific competition can form a self-sustaining island population without human support.
1966 年至 1969 年间，Bernhard Grzimek（法兰克福动物学会，FZS）将之前在欧洲机构饲养的黑猩猩（Pan troglodytes）引入坦桑尼亚维多利亚湖的 Rubondo 岛。早期的出版物报告了释放的动物数量不同，并且所有的创始者都来自西非。我们通过查阅存档的 FZS 记录和对现存后代的遗传分析，对这些假设进行了修正。因此，17 只黑猩猩分四批运往非洲，雌雄比例为 3:8、1:0、1:0 和 2:2；一只雌性在运输过程中死亡。因此，总共释放了 16 只黑猩猩。FZS 和血统记录仅将 19%的创始者的起源地分配到西非，而将 56%的创始者的起源地分配为“非洲”。尽管如此，血统记录表明，没有任何创始者是圈养出生的。此外，我们基于当前后代的生物样本进行的遗传分析表明，它们的祖先的地理起源可以追溯到西非（P. t. verus）和中非（P. t. troglodytes）。根据个体数量和夜间巢穴的计数，我们估计自 1969 年以来，到 2014 年，该种群已增长到约 35 只（年增长率为 3.3%）。因此，在没有人类支持的情况下，被释放到一个没有捕食者或狩猎压力、栖息地破坏和同物种竞争的大型森林岛屿上的黑猩猩可以形成一个自我维持的岛屿种群。
