Playful expressions of one-year-old chimpanzee infants in social and solitary play contexts

Knowledge of the context and development of playful expressions in chimpanzees is limited because research has tended to focus on social play, on older subjects, and on the communicative signaling function of expressions. Here we explore the rate of playful facial and body expressions in solitary and social play, changes from 12- to 15-months of age, and the extent to which social partners match expressions, which may illuminate a route through which context influences expression. Naturalistic observations of seven chimpanzee infants (Pan troglodytes) were conducted at Chester Zoo, UK (n = 4), and Primate Research Institute, Japan (n = 3), and at two ages, 12 months and 15 months. No group or age differences were found in the rate of infant playful expressions. However, modalities of playful expression varied with type of play: in social play, the rate of play faces was high, whereas in solitary play, the rate of body expressions was high. Among the most frequent types of play, mild contact social play had the highest rates of play faces and multi-modal expressions (often play faces with hitting). Social partners matched both infant play faces and infant body expressions, but play faces were matched at a significantly higher rate that increased with age. Matched expression rates were highest when playing with peers despite infant expressiveness being highest when playing with older chimpanzees. Given that playful expressions emerge early in life and continue to occur in solitary contexts through the second year of life, we suggest that the play face and certain body behaviors are emotional expressions of joy, and that such expressions develop additional social functions through interactions with peers and older social partners

<News> Bush Fire Control Using Arbors in Green Corridor Project at Bossou

SIGLEAvailable from British Library Document Supply Centre- DSC:DX178374 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

The Lisu people’s traditional natural philosophy and its potential impact on conservation planning in the Laojun Mountain region, Yunnan Province, China

In this study, we explored a conservation process from an ethnoprimatological perspective for the management of national parks and nature reserves. We accumulated attitude and knowledge data on the traditional culture, religion, and current attitudes to conservation of rural and urban groups of ethnic Lisu people, who live in the village of Liju or have migrated to urban areas, respectively. The data clearly indicated that most of the interviewees had similar feelings and attitudes toward the conservation of Yunnan snub-nosed monkeys (Rhinopithecus bieti) and Laojun Mountain National Park (LMNP), irrespective of whether they live in or have moved away from their home village, or if their educational background differs. Both the rural (96.6%) and urban (100%) interviewees expressed their deep affection for Yunnan snub-nosed monkeys and supported (90.3% and 89.0%, respectively) the seasonal closure of mountainous areas for conservation purposes. The Lisu peoples culture, history, and traditions were evaluated with regards to the developing trend for environmentalism, and their advanced attitudes toward environmental protection and resource utilization exceeded our expectations. The results of this study show huge potential for the optimal mitigation of human-animal conflict in the context of conservation planning not only for LMNP but also for other national parks and nature reserves

Longevity and mortality of captive chimpanzees in Japan from 1921 to 2018

日本の飼育チンパンジーの平均寿命を算出. 京都大学プレスリリース. 2019-10-08.Utilizing the Great Ape Information Network (GAIN), an open-access nationwide database containing the detailed life history information of all apes who have lived or currently reside in Japan, we present a robust chimpanzee life table by single year of age and sex including 821 individuals spanning nearly a century, current through March 11, 2019. While the demographic composition and status of captive chimpanzees in Japan has been previously reported, longevity and mortality statistics have not. We show that female and male survivorship do not differ significantly, and that a live-born chimpanzee in Japan can expect to live 28.3 years (females 26.3, males 30.3). Life expectancy increases to 34.6 years (females 33.4, males 35.7) for individuals who reach one year of age, and to 40.4 years (females 39.2, males 41.5) for those who survive to adulthood. The oldest chimpanzee in Japan, a wild-born male, lived an estimated 68 years. One in six infants are stillborn, and nearly 80% of all infants born alive survive beyond their first birthday. Finally, we report that a seasonal death pattern exists and chimpanzees in Japan are more likely to decease in the winter months (Dec–Feb) than in any other season

Landscaping the behavioural ecology of primate stone tool use

Ecology is fundamental in the development, transmission, and perpetuity of primate technology. Previous studies on tool site selection have addressed the relevance of targeted resources and raw materials for tools, but few have considered the broader foraging landscape. In this landscape-scale study of the ecological contexts of wild chimpanzee (Pan troglodytes verus) tool use, we investigated the conditions required for nut-cracking to occur and persist in discrete locations at the long-term field site of Bossou, Guinea. We examined this at three levels: selection, frequency of use, and inactivity. We collected data on plant foods, nut trees, and raw materials using transect and quadrat methods, and conducted forest-wide surveys to map the location of nests and watercourses. We analysed data at the quadrat level (n = 82) using generalised linear models and descriptive statistics. We found that, further to the presence of a nut tree and availability of raw materials, abundance of food-providing trees as well as proximity to nest sites were significant predictors of nut-cracking occurrence. This suggests that the spatial distribution of nut-cracking sites is mediated by the broader behavioural landscape and is influenced by non-extractive foraging of perennial resources and non-foraging activities. Additionally, the number of functional tools was greater at sites with higher nut-cracking frequency, and was negatively correlated with site inactivity. Our research indicates that the technological landscape of Bossou chimpanzees shares affinities with the 'favoured places' model of hominin site formation, providing a comparative framework for reconstructing landscape-scale patterns of ancient human behaviour. A French translation of this abstract is provided in theelectronic supplementary information: EMS 2.info:eu-repo/semantics/publishedVersio

Chimpanzee choice rates in competitive games match equilibrium game theory predictions

The capacity for strategic thinking about the payoff-relevant actions of conspecifics is not well understood across species. We use game theory to make predictions about choices and temporal dynamics in three abstract competitive situations with chimpanzee participants. Frequencies of chimpanzee choices are extremely close to equilibrium (accurate-guessing) predictions, and shift as payoffs change, just as equilibrium theory predicts. The chimpanzee choices are also closer to the equilibrium prediction, and more responsive to past history and payoff changes, than two samples of human choices from experiments in which humans were also initially uninformed about opponent payoffs and could not communicate verbally. The results are consistent with a tentative interpretation of game theory as explaining evolved behavior, with the additional hypothesis that chimpanzees may retain or practice a specialized capacity to adjust strategy choice during competition to perform at least as well as, or better than, humans have

Published online in Wiley InterScience (www.interscience.wiley.com). r

We present a detailed study of ant-dipping among the wild chimpanzees (Pan troglodytes verus) of Bossou, in southeastern Guinea, West Africa. Observations suggest a strong influence of prey (Dorylus spp.) characteristics, including aggressiveness and/or gregariousness, on tool length and technique employed by the chimpanzees. Bossou chimpanzees exhibit two ant-dipping techniques: 1) direct mouthing, and 2) pull-through. In addition, they were observed dipping for several species of Dorylus ants, classed into two categories: Red and Black. Tool length was longer when dipping in higher-risk contexts, i.e., at the ants&apos; nest site or on Black ants. The pull-through technique was almost exclusively associated with dipping at the nest site. This latter technique was associated with tools over 50 cm long, whereas direct mouthing was the only technique observed with tools o50 cm long. Our experimental findings, together with our observations on the behavior of the chimpanzees, suggest that at the nest, the pull-through technique was a more efficient technique than direct mouthing. We review our results in the context of ant-dipping observed at two other long-term chimpanzee study sites, i.e., Gombe (Tanzania) and Taï (Côte d&apos;Ivoire), where differences in tool length, technique used, and focal Dorylus ant species have been reported. Finally, we urge similar detailed studies of this tool-use behavior in both Gombe and Taï to shed further light upon our results and their implications. Am

New indices to characterize drawing behavior in humans (Homo sapiens) and chimpanzees (Pan troglodytes)

Techniques used in cave art suggest that drawing skills emerged long before the oldest known representative human productions (44, 000 years BC). This study seeks to improve our knowledge of the evolutionary origins and the ontogenetic development of drawing behavior by studying drawings of humans (N = 178, 3- to 10-year-old children and adults) and chimpanzees (N = 5). Drawings were characterized with an innovative index based on spatial measures which provides the degree of efficiency for the lines that are drawn. Results showed that this index was lowest in chimpanzees, increased and reached its maximum between 5-year-old and 10-year-old children and decreased in adults, whose drawing efficiency was reduced by the addition of details. Drawings of chimpanzees are not random suggesting that their movements are constrained by cognitive or locomotor aspect and we cannot conclude to the absence of representativeness. We also used indices based on colors and time and asked children about what they drew. These indices can be considered relevant tools to improve our understanding of drawing development and evolution in hominids