RESUMO
Groups of animals (including humans) may show flexible grouping patterns, in which temporary aggregations or subgroups come together and split, changing composition over short temporal scales, (i.e. fission and fusion). A high degree of fission-fusion dynamics may constrain the regulation of social relationships, introducing uncertainty in interactions between group members. Here we use Shannon's entropy to quantify the predictability of subgroup composition for three species known to differ in the way their subgroups come together and split over time: spider monkeys (Ateles geoffroyi), chimpanzees (Pan troglodytes) and geladas (Theropithecus gelada). We formulate a random expectation of entropy that considers subgroup size variation and sample size, against which the observed entropy in subgroup composition can be compared. Using the theory of set partitioning, we also develop a method to estimate the number of subgroups that the group is likely to be divided into, based on the composition and size of single focal subgroups. Our results indicate that Shannon's entropy and the estimated number of subgroups present at a given time provide quantitative metrics of uncertainty in the social environment (within which social relationships must be regulated) for groups with different degrees of fission-fusion dynamics. These metrics also represent an indirect quantification of the cognitive challenges posed by socially dynamic environments. Overall, our novel methodological approach provides new insight for understanding the evolution of social complexity and the mechanisms to cope with the uncertainty that results from fission-fusion dynamics.
Assuntos
Atelinae/fisiologia , Pan troglodytes/fisiologia , Comportamento Social , Theropithecus/fisiologia , Animais , Comportamento Animal , IncertezaAssuntos
Longevidade/fisiologia , Adulto , Idoso , Envelhecimento , Animais , Apolipoproteína E3/genética , Apolipoproteína E3/imunologia , Apolipoproteína E4/genética , Aterosclerose/genética , Aterosclerose/história , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/história , Dieta , Antigo Egito , Variação Genética/imunologia , História Antiga , Humanos , Imunidade/genética , Longevidade/genética , Longevidade/imunologia , Carne , Pessoa de Meia-Idade , Múmias , Pan troglodytes/fisiologia , Peru , Especificidade da EspécieRESUMO
All investigated cases of habitual tool use in wild chimpanzees and capuchin monkeys include youngsters encountering durable artefacts, most often in a supportive social context. We propose that enduring artefacts associated with tool use, such as previously used tools, partly processed food items and residual material from previous activity, aid non-human primates to learn to use tools, and to develop expertise in their use, thus contributing to traditional technologies in non-humans. Therefore, social contributions to tool use can be considered as situated in the three dimensions of Euclidean space, and in the fourth dimension of time. This notion expands the contribution of social context to learning a skill beyond the immediate presence of a model nearby. We provide examples supporting this hypothesis from wild bearded capuchin monkeys and chimpanzees, and suggest avenues for future research.
Assuntos
Cebus/fisiologia , Cebus/psicologia , Aprendizagem , Pan troglodytes/fisiologia , Pan troglodytes/psicologia , Comportamento de Utilização de Ferramentas , Animais , Brasil , Feminino , Modelos Lineares , Estudos Longitudinais , Masculino , Nozes , Fatores de TempoRESUMO
Obesity is a risk factor for several diseases including type 2 diabetes and cardiovascular disease. The aim of this study was to compare the relationships of waist circumference and body weight with circulating markers of metabolic, cardiovascular, and hepatic function in chimpanzees (Pan troglodytes). After a 12-h fast, blood was collected from 39 adult captive chimpanzees for measurement of serum glucose, BUN, creatinine, albumin, cholesterol, ALT, AST, ALP, total and direct bilirubin, triglyceride, and insulin, and waist circumference and body weight were measured. Waist circumference was positively correlated with systolic and diastolic blood pressure, glucose, insulin resistance as estimated by the homeostatic model assessment method, and albumin in female chimpanzees and with triglyceride in female and male chimpanzees. Body weight was correlated significantly with systolic and diastolic blood pressure in female chimpanzees and triglyceride in male chimpanzees. Male chimpanzees were heavier and had lower diastolic blood pressure, greater creatinine, albumin, AST, ALP, total bilirubin, and direct bilirubin values than did female chimpanzees. The relationships between waist circumference and blood pressure and triglyceride are consistent with those reported in humans and other primate species. In conclusion, our study is the first work to demonstrate a relationship between waist circumference and metabolic risk factors in chimpanzees. Results demonstrated that waist circumference was associated with more metabolic risk factors than was body weight, particularly in female chimpanzees.