Integrating physiology, behavior, and energetics: Biologging in a free-living arctic hibernator.

The use of animal-borne instruments (ABIs), including biologgers and biotransmitters, has played an integral role in advancing our understanding of adjustments made by animals in their physiology and behavior across their annual and daily cycles and in response to weather and environmental change. Here, we review our research employing body temperature (Tb), light, and acceleration biologgers to measure patterns of physiology and behavior of a free-living, semi-fossorial hibernator, the arctic ground squirrel (Urocitellus parryii). We have used these devices to address a variety of physiological, ecological, and evolutionary questions within the fields of hibernation physiology, phenology, behavioral ecology, and chronobiology. We have also combined biologging with other approaches, such as endocrinology and tracking the thermal environment, to provide insights into the physiological mechanisms that underlie fundamental questions in biology including physiological performance trade-offs, timing and functional energetics. Finally, we explore the practical and methodological considerations that need to be addressed in biologging studies of free-living vertebrates and discuss future technological advancements that will increase the power and potential of biologging as a tool for assessing physiological function in dynamic and changing environments.