Newswise — Rodents play a role in many scientific studies, but rarely in investigations of social behavior. In the South American caviomorphs, however, researchers have found an excellent subject to explore the evolution of sociality in rodents. Encompassing 14 family designations and habitats ranging from high-altitude shrublands to tropical forests to coastal areas in South America, the caviomorph suborder shows great diversity. These rodents offer an opportunity to compare social systems within and among groups.
The February 2011 issue of the Journal of Mammalogy contains a special feature section of seven articles focusing on the social systems of the South American caviomorphs (New World hystricognaths). With these rodents, researchers hope to test new hypotheses and demonstrate the utility of caviomorphs as a model for research on sociality.
The causes and consequences of social variation in this suborder were little studied before the 1990s. The current research topics include size and social structure of groups, mating and burrowing behaviors, and adaptations to environmental factors.
The research finds that one species of these rodents, the capybara, lives in stable social groups, with the size of the groups defined by local population density. In a different family, the degus, the dynamics of social groups appear unaffected by population density. These studies tell us that other influences besides ecological constraints alone are needed to explain this social evolution.
Other articles discuss diversity in mating systems. Groups of echimyid rodents range from monogamy to polygyny. One author developed a model to predict these systems, while others focus on behavioral and environmental factors of several groups within the caviomorphs that may explain the diversity.
Stimulating new directions in research is one of the main objectives of this special feature. Two articles review current understanding and seek to identify new areas of investigation. Future research should include studies of brain mechanisms, behavioral endocrinology, fitness consequences, and disease ecology as they relate to the evolution of sociality in this interesting group of rodents.
Full text of the introductory article in this Special Feature on caviomorph rodent social systems, Journal of Mammalogy, Vol. 92, No. 1, February 2011, is available at: http://www.asmjournals.org/doi/full/10.1644/10-MAMM-S-187.1
About the Journal of MammalogyThe Journal of Mammalogy, the flagship publication of the American Society of Mammalogists, is produced six times per year. A highly respected scientific journal, it details the latest research in the science of mammalogy and was recently named one of the top 100 most influential journals of biology and medicine in the last century by the Special Libraries Association. For more information, visit http://www.mammalogy.org/.
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