The literature on manual laterality in nonhuman primates provides inconsistent and inconclusive findings and is plagued by methodological issues (e.g., small samples, inconsistency in methods, inappropriate measures) and gaps. Few data are available on bonobos and these are only from small samples and for relatively simple tasks. We examined laterality in a large sample of bonobos for a complex task. We tested 48 bonobos from Lola Ya Bonobo sanctuary (DR Congo) in an extension of our previous study of 29 bonobos from 3 European zoos. We assessed hand preferences using the tube task, which involves bimanual coordination: one hand extracts food from a tube that is held by the other hand. This task is a good measure of laterality and it has been used in other studies. We recorded events (frequency) and independent bouts of food extraction. We found significant manual laterality, which was not influenced by the settings or rearing history. We observed little effect of sex and found an influence of age, with greater right hand use in adults. The laterality was marked, with strong preferences and most individuals being lateralized (when analyzing frequency). We found individual preferences, with no group-level bias, even when we combined the data from the sanctuary and the zoos to enlarge the sample to 77. These first data, for a complex task and based on a large sample, are consistent with previous findings in Int bonobos and in other nonhuman primate species for a variety of tasks. They suggest that, despite particular features in terms of proximity to humans, language and bipedalism, bonobos do not display a laterality that is more marked or more similar to human handedness compared to that of other nonhuman primate species.

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Biodiversity is being lost at unprecedented rates. Limited conservation resources must be prioritized strategically to maximize impact. Here we introduce novel methods to assess a small-scale conservation education program in the Democratic Republic of Congo. Lola ya Bonobo is the world's only sanctuary for one of humans' two closest living relatives, bonobos, orphaned by the illegal trade in bushmeat and exotic pets. The sanctuary is situated on the edge of the country's capital, Kinshasa, its most densely populated region and a hub for the illegal wildlife trade that is imperiling bonobos and other endangered species. Lola ya Bonobo implements an education program specifically designed to combat this trade. Previous evaluation demonstrated the program's efficacy in transmitting conservation knowledge to children. In Study 1, we use novel implicit tests to measure conservation attitudes before and after an educational visit and document a significant increase in children's pro-conservation attitudes following direct exposure to bonobos and the education program. In Study 2, we show that adults exhibit high levels of conservation knowledge even before visiting the sanctuary, likely due to the sanctuary's longstanding education efforts in Kinshasa. In Study 3, we explored adults' empathetic attitudes toward bonobos before and after the sanctuary tour. Our results support the conservation education hypothesis that conservation education has improved relevant knowledge and attitudes in Kinshasa. Crucially, the present study validates new methods for implicitly assessing attitudes about environmental and social issues. These methods overcome typical biases in survey sampling and can be employed in diverse populations, including those with low literacy rates.

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