A time-energy analysis of daytime surface activity in degus, Octodon degus

Abstract

We present an analysis of time and energy allocation in a day-active caviomorph rodent, the degu, Octodon degus, in central Chile. We quantified components of surface activity in the field on a daily basis in individual degus near the time of the summer solstice, when conditions of heat and aridity were also at a seasonal extreme, in order to answer the following questions. Does the absolute time available for surface activity limit performance? Does the allocation of time and energy for locomotion place a functionally significant limitation on overall energy balance and performance? Degus spent about 2/3 of their above-ground time foraging; they remained stationary about 88 % of the time, walked around slowly about 10 %, and were running rapidly from one point to another only about 2 % of the time. Net locomotion costs (for walking and running combined) were computed to be only 2.2 % of total daily energy expenditure. This low net allocation of time and energy to locomotion, taken tog