Self-organization in the dynamics of huddling behavior in Octodon degus in two contrasting seasons

Abstract

In small mammals, huddling appears as an efficient response to low temperature with important consequences in energy saving, which in turn affect individual fitness. It has been proposed that this behavior is a self-organized process. However, to prove self-organization, it is necessary to study the dynamics of huddling, ruling out the presence of leaders. The objectives of this study were to determine the dynamics of huddling at different temperatures in Octodon degus, documenting the presence or absence of leaders, and to study the consistency of this behavior in two contrasting seasons. We found that huddling dynamics did not indicate the presence of leader initiators of the clustering at lower temperatures. There was no deterministic pattern in huddling dynamics, in any period or at any temperature, suggesting a behavior triggered spontaneously without any order, hierarchy, or recipes. The effect of temperature on huddling behavior was marked and similar in both seasons. The variability of the huddled groups was greater at higher temperatures, which is explained by a greater movement of individuals and more frequent variations in the number and size of the groups at higher temperatures. The results describe huddling as a self-organized behavior, more economical than other physiological processes and therefore preserved by natural selection. This increases its importance for survival and fitness given the significant reduction in energy expenditure achieved under conditions of low temperatures and reduced availability of food, such as during the breeding season of O. degus.