Estimates for energy expenditure in free-living animals using acceleration proxies: A reappraisal

It is fundamentally important for many animal ecologists to quantify the costs of animal activities, although it is not straightforward to do so. The recording of triaxial acceleration by animal-attached devices has been proposed as a way forward for this, with the specific suggestion that dynamic body acceleration (DBA) be used as a proxy for movement-based power. Dynamic body acceleration has now been validated frequently, both in the laboratory and in the field, although the literature still shows that some aspects of DBA theory and practice are misunderstood. Here, we examine the theory behind DBA and employ modelling approaches to assess factors that affect the link between DBA and energy expenditure, from the deployment of the tag, through to the calibration of DBA with energy use in laboratory and field settings. Using data from a range of species and movement modes, we illustrate that vectorial and additive DBA metrics are proportional to each other. Either can be used as a proxy for energy and summed to estimate total energy expended over a given period, or divided by time to give a proxy for movement-related metabolic power. Nonetheless, we highlight how the ability of DBA to predict metabolic rate declines as the contribution of non-movement-related factors, such as heat production, increases. Overall, DBA seems to be a substantive proxy for movement-based power but consideration of other movement-related metrics, such as the static body acceleration and the rate of change of body pitch and roll, may enable researchers to refine movement-based metabolic costs, particularly in animals where movement is not characterized by marked changes in body acceleration.Fil: Wilson, Rory P.. Swansea University; Reino UnidoFil: Börger, Luca. Swansea University; Reino UnidoFil: Holton, Mark. Swansea University; Reino UnidoFil: Scantlebury, D. Michael. The Queens University of Belfast; IrlandaFil: Gómez Laich, Agustina Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Quintana, Flavio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Rosell, Frank. University of South‐Eastern Norway; NoruegaFil: Graf, Patricia M.. Universitat Fur Bodenkultur Wien; Austria. University of Ljubljana; EsloveniaFil: Williams, Hannah. Swansea University; Reino UnidoFil: Gunner, Richard. Swansea University; Reino UnidoFil: Hopkins, Lloyd. Swansea University; Reino UnidoFil: Marks, Nikki. The Queens University of Belfast; IrlandaFil: Geraldi, Nathan R.. King Abdullah University of Science and Technology; Arabia SauditaFil: Duarte, Carlos M.. King Abdullah University of Science and Technology; Arabia SauditaFil: Scott, Rebecca. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: Strano, Michael S.. Massachusetts Institute of Technology; Estados UnidosFil: Robotka, Hermina. Max Planck Institute für Ornithologie; AlemaniaFil: Eizaguirre, Christophe. , Queen Mary University of London; Reino UnidoFil: Fahlman, Andreas. undación Oceanogràfic de la Comunidad Valenciana; EspañaFil: Shepard, Emily L. C.. Swansea University; Reino Unido. Max Planck Institute für Ornithologie; Alemani