1,721,709 research outputs found
Territory Characteristics among Three Neighboring Chimpanzee Communities in the Taï National Park, Côte d'Ivoire
No full textWe studied territory characteristics among three neighboring chimpanzee communities in the Tai National Park, Cote d'lvoire, and compared them with other chimpanzee populations We characterized territories and ranging patterns by analyzing six variables: (1) territory size, (2) overlap zone, (3) territory utilization, (4) core area, (5) territory shift, and (6) travel distance. Data collection covered a period of IO mo, during which we simultaneously sampled the local positions of mostly large parties, including males in each community, in 30-min intervals In Tai; chimpanzees used territories in a clumped way, with small central core areas being used preferentially over large peripheral areas Although overlap zones between study communities mainly represented infrequently visited peripheral areas overlap zones with all neighboring communities also included intensively used central areas. Territory utilization was not strongly seasonal, with no major shift of activity center or shift of areas used over consecutive months. However, we observed shorter daily travel distances in times of low food availability Territory sizes of Tai chimpanzees tended to be larger than territories in other chimpanzee communities, presumably because high food availability allows for economical defense of territorial borders and time investment in territorial activities. Therefore we suggest, that use of territory in Tai chimpanzees is strongly influenced by intercommunity relations To understand differences in territory characteristics between various populations, it is of major importance to consider not only the intracommunity but also the intercommunity context
When to choose which tool: Multidimensional and conditional selection of nut-cracking hammers in wild chimpanzees
No full textInvestigating cognitively complex behaviours in their natural ecological context provides essential insights into the adaptive value of animal cognition. In this study, we investigated the selection of hammers used for cracking Coula nuts by wild chimpanzees, Pan troglodytes verus, in the Taï National Park, CÔte d'Ivoire, taking account of the availability of potential tools at the site and time of tool selection. Using GLMMs and focal follows of five adult females, we estimated the probability of an object being selected as a hammer according to its physical properties, transport distance and the location of the anvil on the ground or in trees. We found that chimpanzees took account of several variables at the same time (multidimensionality) when selecting nut-cracking tools and that their selection for hammer weight was adjusted to the state/value of other variables (conditionality). In particular, chimpanzees (1) preferred stones over wooden clubs and hard woods over soft woods; (2) selected heavy stones, but relatively lighter wooden hammers; (3) selected increasingly heavier hammers the closer they were to the anvil; and (4) selected lighter hammers when they were going to crack nuts on a tree. The latter two results represent instances of conditional tool selection based on the next steps in an operational sequence (transport and/or use of the tool in a stable or unstable location) and suggest that chimpanzees anticipated future events when they chose a tool. This large set of conditional rules suggests a high level of cognitive sophistication in a tool use task. Our results represent a compelling example of how powerful cognitive skills allow the optimization of an ecologically relevant foraging activity, supporting a food extraction hypothesis for the evolution of complex cognition in our closest relatives
Chimpanzee hunting behavior
Full text linkThe pursuit, capture and consumption of small-and medium-sized vertebrates, appears to be typical of all chimpanzee (Pan troglodytes) populations, although large variation exists. Red colobus monkeys (Piliocolobus sp.) appear to be the preferred prey but intensity and frequency of hunting varies from month to month and between populations. Hunting is a predominately male activity and is typically opportunistic, although there is some evidence of searching for prey. The degree of cooperation during hunting, as well as prey selection, varies between East and West African populations and may be related to the way the kill is divided: in West Africa, hunters often collaborate, with kills tending to be shared according to participation, whereas in East Africa, the kill is typically divided tactically by the male in possession of the carcass, trading meat with females in return for sex or with other males to strengthen alliances, and cooperation in hunting is more limited. The adaptive function of chimpanzee hunting is not well understood, although it appears that it may be both a means to acquire a nutritionally valuable commodity that can then be traded and as a means for males to display their prowess and reliability to one another
Boesch, C., Hohmann, G. & Marchant, L. F. (eds). — Behavioural diversity in chimpanzees and bonobos. Cambridge University Press, Cambridge, New York, Melbourne, Madrid & Cape Town. 2002
No full textErard Christian. Boesch, C., Hohmann, G. & Marchant, L. F. (eds). — Behavioural diversity in chimpanzees and bonobos. Cambridge University Press, Cambridge, New York, Melbourne, Madrid & Cape Town. 2002. In: Revue d'Écologie (La Terre et La Vie), tome 59, n°4, 2004. pp. 607-609
The Hunting Behavior and Carnivory of Wild Chimpanzees
Full text linkThe pursuit, capture and consumption of small- and medium-sized vertebrates appear to be typical of all chimpanzee (Pan troglodytes) populations, although large variation exists. Red colobus monkeys (Piliocolobus sp.) appear to be the preferred prey, but intensity and frequency of hunting varies from month to month and among populations. Hunting is a predominately male activity and is typically opportunistic, although there is some evidence of searching for prey. The degree of cooperation during hunting, as well as prey selection, varies between East and West African populations and may be related to the way the kill is divided: in West Africa, hunters often collaborate, with kills tending to be shared according to participation, whereas in East Africa, cooperation in hunting is more limited and the kill is typically consumed selfishly, or divided in response to harassment (begging) by others. In some cases it may be shared tactically, trading meat with other males to strengthen alliances. The adaptive function of chimpanzee hunting is not well understood and a variety of hypotheses have been proposed. Ideas that chimpanzees hunt to make up for nutritional shortfalls, or to acquire meat to trade for sex, have failed to find empirical support, while recent work favors nutritional benefits of some kind. Nevertheless, cross-population studies evaluating multiple hypotheses are in their infancy, and there is much to be learned. In particular, very little is known about hunting of non-primates, particularly ungulates, or the impact that variation in levels of hunting, and of carcasses to share and consume, has on patterns of chimpanzee behavior. If one goal of studying this topic is to shed light on the behavioral ecology of hominins, then efforts to understand the diversity of hunting and carnivory in wild chimpanzees are needed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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