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Cavia magna wild guinea pig (Rodentia: Caviidae) behavior and social organization

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Author(s):
Elisa Augusto dos Santos
Total Authors: 1
Document type: Master's Dissertation
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Instituto de Psicologia (IP/SBD)
Defense date:
Examining board members:
Patricia Izar Mauro; Marcos Tokuda; Rosana Suemi Tokumaru
Advisor: Patricia Izar Mauro
Abstract

Socioecology studies social systems applying the behavioral ecology principles. Studying rodents social systems represents a valuable opportunity once this group shows high variations on social behavior, which may be an adaptation selected in evolutionary past and/or an adaptative feedback to the ecological context. Investigate the social organization flexibility by studying cavies is relevant because of its relative behavioral rigidity, despite their occupation of different environments. In this context, we intend to evaluate our hypothesis on the Cavia magna, cavie social organization: it depends on current ecological factors, being an adaptive answer. C. magna is an herbivore found on northern Uruguay and south of Brazil. The alternative hypothesis is that the social organization is an adaptive answer, limited by reaction rules selected on the past. The cavies was observed in a coast urban area, inside of the Instituto Federal de Santa Catarina (IFSC), in continental Florianópolis, Brazil. The population is isolated in a small area with low predatory risk, being similar to an insulated habitat. We collected data on social interaction, interindividual distances during foraging, grouping pattern and sexual ratio. This data was compared to the available data of Cavia intermedia, from the Moleques do Sul archipelago, specie that was probably derived from C. magna and presents adaptations to the insular habitat. Cavies were observed for 60 days in cold-dry and hot-wet season. We have concluded that the studied C. magna population is social, given that we have found relatively large mean groups size, high Association Indexes between individuals, and preferred associations in three clusters with typical harem structure. We have also found that the population is polygynous, because the access to females differed between male individuals, and the males performed significantly more agonistic behaviors than females. The existence of a dominance hierarchy and the absence of male territorial behavior pointed to polygyny without defense. Even though the studied social system is similar to the one observed on C. intermedia, we did not encounter typical insular syndrome features on C. magna. Accordingly, we have supported the hypothesis that the cavies social organization is an adaptive answer (AU)

FAPESP's process: 11/05455-0 - Foraging behavior of Cavia magna cavies in Serra do Tabuleiro Estadual Park, Santa Catarina, Brazil
Grantee:Elisa Augusto dos Santos
Support Opportunities: Scholarships in Brazil - Master