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[This corrects the article DOI: 10.1371/journal.pone.0292984.].

Chimpanzees are humanity's closest living relations and are of enduring interest to a range of sciences, from anthropology to zoology. In the West, many know of the pioneering work of Jane Goodall, whose studies of these apes at Gombe in Tanzania are justly famous. Less well-known, but equally important, are the studies carried out by Toshisada Nishida on the eastern shore of Lake Tanganyika. Comparison between the two sites yields both notable similarities and startling contrasts. Nishida has written a comprehensive synthesis of his work on the behaviour and ecology of the chimpanzees of the Mahale Mountains. With topics ranging from individual development to population-specific behavioural patterns, it reveals the complexity of social life, from male struggles for dominant status to female travails in raising offspring. Richly illustrated, the author blends anecdotes with powerful data to explore the fascinating world of the chimpanzees of the lakeshore.

Recollecting the what-where-when of an episode, or episodic-like memory, has been established in corvids and rodents. In humans, a linkage between remembering the past and imagining the future has been recognised. While chimpanzees can plan for the future, their episodic-like memory has hardly been investigated. We tested chimpanzees (Pan troglodytes) with an adapted food-caching paradigm. They observed the baiting of two locations amongst four and chose one after a given delay (15 min, 1 h or 5 h). We used two combinations of food types, a preferred and a less preferred food that disappeared at different rates. The subjects had to base their choices on the time elapsed since baiting, and on their memory of which food was where. They could recover either their preferred food or the one that remained present. All animals failed to obtain the preferred or present foods above chance levels. They were like-wise unsuccessful at choosing baited cups above chance levels. The subjects, thus, failed to use any feature of the baiting events to guide their choices. Nonetheless, their choices were not random, but the result of a developed location-based association strategy. Choices in the second half of the study correlated with the rewards obtained at each location in the first half of the study, independent from the choices made for each location in the first half of the study. This simple location-based strategy yielded a fair amount of food. The animals' failure to remember the what-where-when in the presented set-up may be due to the complexity of the task, rather than an inability to form episodic-like memories, as they even failed to remember what was where after 15 minutes.

为提高动物医疗行为训练水平, 提升广大民众对野生动物的保护意识, 针对黑猩猩 (Pan troglodytes) 开展了医疗行为训练并结合科普讲解进行展示。训练期为6个月, 训练动物为圈养成年黑猩猩雌雄各1只, 训练包含测额温、触诊、B超检查和采血等项目, 训练地点分为室内训练和展厅2个部分。通过桥接食物-哨声配对机制在人-黑猩猩之间建立有效地沟通方式, 为后续训练建立基础。经过系统训练后, 2只黑猩猩基本完成训练目标, 可以向游客展示黑猩猩医疗行为。动物医疗行为训练方便对动物的诊治, 可以提升动物福利水平, 践行动物保护理念, 同时也有利于传播科普知识, 为其他动物园的动物医疗行为训练提供借鉴。

2017年冬季, 为检验杭州动物园黑猩猩冬季饲料是否在行为和营养上满足需求, 粗略计算黑猩猩冬季饲料营养成分, 与日本、阿根廷、上海野生动物园、国内动物园的日粮营养成分对比, 同时参照中国营养学会推荐的人类膳食营养平衡标准和AZA黑猩猩饲养指南, 结合杭州动物园黑猩猩实际生长发育情况, 评估黑猩猩冬季饲料。结果显示, 杭州动物园冬季黑猩猩饲料在营养成分上, 总能量 (105—159 MJ) , 高于黑猩猩维持能量 (711—8372 MJ) , 蛋白质 (79—119 g) 、脂肪 (55—83 g) 、碳水化合物 (401—602 g) 、微量元素总含量符合人的营养素参考摄入量和AZA黑猩猩饲养指南；在饲料种类上, 蔬菜、水果、奶类的比例与已知5个动物园饲料总量均值之间没有显著差异 (P>005) , 水果总量高于推荐量, 无植物类食物供应。杭州动物在黑猩猩冬季饲料种类和营养成分上可以满足基本需求, 但仍需改进, 建议在满足营养需求的基础上, 通过减少或更换水果、增加植物类饲料、增加干粮纤维比例等增加日粮的纤维含量。

Humans have the largest cerebral cortex among primates. The question of whether association cortex, particularly prefrontal cortex (PFC), is disproportionately larger in humans compared with nonhuman primates is controversial: Some studies report that human PFC is relatively larger, whereas others report a more uniform PFC scaling. We address this controversy using MRI-derived cortical surfaces of many individual humans, chimpanzees, and macaques. We present two parcellation-based PFC delineations based on cytoarchitecture and function and show that a previously used morphological surrogate (cortex anterior to the genu of the corpus callosum) substantially underestimates PFC extent, especially in humans. We find that the proportion of cortical gray matter occupied by PFC in humans is up to 1.9-fold greater than in macaques and 1.2-fold greater than in chimpanzees. The disparity is even more prominent for the proportion of subcortical white matter underlying the PFC, which is 2.4-fold greater in humans than in macaques and 1.7-fold greater than in chimpanzees.

Bonobos (Pan paniscus ), which share a close evolutionary lineage with chimpanzees ( Pan troglodytes ) and humans, offer vital insights into the genetic and developmental propensities underlying human evolution. In this study, we established nine integration-free bonobo induced pluripotent stem cell (iPSC) lines from cryopreserved peripheral blood mononuclear cells using Sendai virus-derived RNA vectors. These iPSCs exhibited key pluripotency gene expression, normal karyotypes, and the capacity for differentiation into neural, mesodermal, and endodermal lineages, including the first successful induction of limb bud mesoderm cells from great ape iPSCs. Comprehensive transcriptome comparisons among bonobo, chimpanzee, and human iPSCs uncovered significant gene expression and retrotransposon divergence between Homo and Pan species, while highlighting minimal differences between bonobos and chimpanzees. Nevertheless, variation in the expression of mitochondrial metabolism-related genes was observed between the Pan species, suggesting potential interspecies differences in metabolic activity. This work provides a valuable platform for investigating the molecular and cellular mechanisms underlying species-specific developmental traits in closely related hominids and sheds light on the evolutionary origins of human characteristics.

Human between-group interactions are highly variable, ranging from violent to tolerant and affiliative. Tolerance between groups is linked to our unique capacity for large-scale cooperation and cumulative culture, but its evolutionary origins are understudied. In chimpanzees, one of our closest living relatives, predominantly hostile between-group interactions impede cooperation and information flow across groups. In contrast, in our other closest living relative, the bonobo, tolerant between-group associations are observed. However, as these associations can be frequent and prolonged and involve social interactions that mirror those within groups, it is unclear whether these bonobos really do belong to separate groups. Alternatively, the bonobo grouping patterns may be homologous to observations from the large Ngogo chimpanzee community, where individuals form within-group neighborhoods despite sharing the same membership in the larger group. To characterize bonobo grouping patterns, we compare the social structure of the Kokolopori bonobos with the chimpanzee group of Ngogo. Using cluster analysis, we find temporally stable clusters only in bonobos. Despite the large spatial overlap and frequent interactions between the bonobo clusters, we identified significant association preference within but not between clusters and a unique space use of each cluster. Although bonobo associations are flexible (i.e., fission–fusion dynamics), cluster membership predicted the bonobo fission compositions and the spatial cohesion of individuals during encounters. These findings suggest the presence of a social system that combines clear in-group/out-group distinction and out-group tolerance in bonobos, offering a unique referential model for the evolution of tolerant between-group interactions in humans.