RESUMO
Communicative complexity relates to social complexity, as individuals in more complex social systems either use more signals or more complex signals than individuals living in less complex ones. Taking the individual group member's perspective, here we examine communicative complexity in relation to social complexity, which arises from two components of social systems: social structure and social organization. We review the concepts of social relationships and social complexity and evaluate their implications for communicative and cognitive complexity using examples from primate species. We focus on spider monkeys (Ateles geoffroyi), as their social organization is characterized by flexibility in grouping dynamics and they use a variety of communicative signals. We conclude that no simple relationship exists among social complexity, communicative complexity and cognitive complexity, with social complexity not necessarily implying cognitive complexity, and communicative and cognitive complexity being independently linked to social complexity. To better understand the commonly implied link between social complexity and cognitive complexity it is crucial to recognize the complementary role of communicative complexity. A more elaborated communicative toolkit provides the needed flexibility to deal with dynamic and multifaceted social relationships and high variation in fission-fusion dynamics. This article is part of the theme issue 'Cognition, communication and social bonds in primates'.
Assuntos
Atelinae , Comportamento Social , Animais , Comunicação , Relações Interpessoais , Primatas/psicologia , Estrutura SocialRESUMO
Self-directed behavior, such as self-scratching (hereafter, scratching), occurs in several taxa across the animal kingdom, including nonhuman primates. There is substantial evidence that scratching is an indicator of anxiety-like emotions in a variety of nonhuman primate species. Despite its importance as a window into emotional states, few studies have investigated scratching in Platyrrhines. We investigated scratching patterns of 24 Geoffroy's spider monkeys (Ateles geoffroyi) belonging to a group living in the Otoch Ma'ax Yetel Kooh protected area in the Yucatàn peninsula (Mexico). We assessed whether scratching could be used as an indicator of anxiety levels in this species by testing predictions based on contexts and behaviors associated with risk and uncertainty. We found no effect of the subject's sex and age, subgroup size, male presence, and the occurrence of fusions between subgroups on scratching rates. Similarly, we found no effect of infant proximity on their mother's scratching rates. Supporting our prediction, we found evidence that isolation from conspecifics affected scratching rates as individuals scratched more frequently the more time they spent isolated. Being in proximity with a partner with a relationship characterized by uncertainty affected scratching rates as individuals scratched more frequently when in proximity with a partner with whom they engaged in embraces (an indicator of uncertainty) than when in proximity with a partner with whom they did not exchange embraces. Our study provides insight into the factors affecting scratching in Geoffroy's spider monkeys, suggesting that scratching may indicate anxiety in this species at least in some contexts and thus opening a window into the emotional experience of another Platyrrhine monkey species.
Assuntos
Ansiedade , Ateles geoffroyi , Animais , Ansiedade/diagnóstico , Ateles geoffroyi/psicologia , Feminino , Masculino , MéxicoRESUMO
Cashew nuts are very nutritious but so well defended by caustic chemicals that very few species eat them. We investigated how wild bearded capuchin monkeys (Sapajus libidinosus) living at Fazenda Boa Vista (FBV; Piauí, Brazil) process cashew nuts (Anacardium spp.) to avoid the caustic chemicals contained in the seed mesocarp. We recorded the behavior of 23 individuals toward fresh (N = 1282) and dry (N = 477) cashew nuts. Adult capuchins used different sets of behaviors to process nuts: rubbing for fresh nuts and tool use for dry nuts. Moreover, adults succeed to open dry nuts both by using teeth and tools. Age and body mass significantly affected success. Signs of discomfort (e.g., chemical burns, drooling) were rare. Young capuchins do not frequently closely observe adults processing cashew nuts, nor eat bits of nut processed by others. Thus, observing the behavior of skillful group members does not seem important for learning how to process cashew nuts, although being together with group members eating cashews is likely to facilitate interest toward nuts and their inclusion into the diet. These findings differ from those obtained when capuchins crack palm nuts, where observations of others cracking nuts and encounters with the artifacts of cracking produced by others are common and support young individuals' persistent practice at cracking. Cashew nut processing by capuchins in FBV appears to differ from that observed in a conspecific population living 320 km apart, where capuchins use tools to open both fresh and dry nuts. Moreover, in the latter population, chemical burns due to cashew caustic compounds appear to be common. The sources of these differences across populations deserve investigation, especially given that social influences on young monkeys learning to open cashew nuts at FBV seem to be nonspecific. Am. J. Primatol. 78:799-815, 2016. © 2016 Wiley Periodicals, Inc.
Assuntos
Anacardium , Cebus , Comportamento de Utilização de Ferramentas , Animais , Comportamento Animal , Brasil , Dieta , NozesRESUMO
Seyfarth's model assumes that female primates derive rank-related benefits from higher-ranking females in exchange for grooming. As a consequence, the model predicts females prefer high-ranking females as grooming partners and compete for the opportunity to groom them. Therefore, allogrooming is expected to be directed up the dominance hierarchy and to occur more often between females with adjacent ranks. Although data from Old World primates generally support the model, studies on the relation between grooming and dominance rank in the New World genus Cebus have found conflicting results, showing considerable variability across groups and species. In this study, we investigated the pattern of grooming in wild tufted capuchin females (Cebus apella nigritus) in Iguazú National Park, Argentina by testing both the assumption (i.e., that females gain rank-related return benefits from grooming) and predictions (i.e., that females direct grooming up the dominance hierarchy and the majority of grooming occurs between females with adjacent ranks) of Seyfarth's model. Study subjects were 9 adult females belonging to a single group. Results showed that grooming was given in return for tolerance during naturally occurring feeding, a benefit that higher-ranking females can more easily grant. Female grooming was directed up the hierarchy and was given more often to partners with similar rank. These findings provide supporting evidence for both the assumption and predictions of Seyfarth's model and represent, more generally, the first evidence of reciprocal behavioural interchanges driven by rank-related benefits in New World female primates.